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Cobalt manganese hydroxides with well-defined nanowire morphology (CoMn-HW) is scalable fabricated by adjusting solution contents, Mn/Co ratio and alkaline species. To further improve the conductivity of CoMn-HW, GO is introduced during fabrication process and reduced to rGO according to the high temperature and alkali atmosphere. By optimizing the adding mass of rGO, CoMn-HW/rGO with sandwiched like structure is successfully synthesized for supercapacitor electrode. The composite delivers a high specific capacitance of 784 F g−1 at current density of 0.5 A g−1, good rate capability (84.2% capacitance retention after current density increase 10 times). Moreover, an asymmetric supercapacitor with CoMn-HW/rGO10 as the positive electrode and active carbon as the negative electrode, is assembled and delivers a maximum energy density of 38.3 Wh kg−1 and power density of 8000 W kg−1, representing its potential in energy storage and conversion systems. • Co, Mn-hydroxides with nanowire morphology is scalable fabricated. • CoMn-HW/rGO with sandwiched like structure is synthesized under optimal synthesis condition. • An asymmetric supercapacitor based on CoMn-HW/rGO and AC is assembled with high energy and power densities. [ABSTRACT FROM AUTHOR]

In this article, ZnCo 2 O 4 nanowires deposited with two kinds of typical layered double hydroxides (Ni–Al,Co–Al LDH) are developed via scalable method. Two materials all display core–shell hierarchical structure. High specific capacitance of 2041 F g−1 and 1586 F g−1 are obtained for ZnCo 2 O 4 @Co–Al LDH and ZnCo 2 O 4 @Ni–Al LDH,respectively. Combining with active surface and synergistic effect, the role of hierarchical structure in enhancing performance is revealed. Moreover, two all solid state supercapacitors based on fabricated materials as positive electrodes, activated carbon as negative electrodes and PVA–KOH as polymer electrolyte are assembled. The maximum power and energy densities of ZnCo 2 O 4 @Co–Al LDH//AC are 6200 W kg−1 and 50.1 Wh kg−1, respectively. While the power and energy densities of ZnCo 2 O 4 @Ni–Al LDH//AC are 3400 W kg−1 and 27.8 Wh kg−1. At last, an energy storage–conversion system, based on solar cell as input device and assembled asymmetric supercapacitor ZnCo 2 O 4 @Co–Al LDH//AC as output device, is integrated as a self–sustaining power device, indicating its potential in practical applications. In this article, ZnCo 2 O 4 nanowires deposited with two kinds of typical layered double hydroxides (LDHs) are developed via scalable method. Combining with active surface and synergistic effect, the role of hierarchical structure of each material in enhancing performance is revealed. Moreover, an energy storage–conversion system, based on solar cell as input device and assembled asymmetric supercapacitor as output device, is integrated as a self–sustaining power device, further indicating its potential in practical applications. Image 1 [ABSTRACT FROM AUTHOR]

A novel three-dimensional (3D) porous nickel-cobalt (Ni-Co) film on nickel foam is successfully prepared and further used as an efficient anode for direct urea-hydrogen peroxide fuel cell (DUHPFC). By varying the cobalt/nickel mole ratios into 0%, 20%, 50%, 80% and 100%, the optimized Ni-Co/Ni foam anode with a ratio of 80% is obtained in terms of the best cell performance among five anodes. Effects of the KOH and urea concentrations, the flow rate and operation temperature on the fuel cell performance are investigated. Results show DUHPFC with the 3D Ni-Co/Ni foam anode exhibits a higher performance than those reported direct urea fuel cells. The cell gives an open circuit voltage of 0.83 V and a peak power density as high as 17.4 and 31.5 mW cm −2 at 20 °C and 70 °C, respectively, when operating on 7.0 mol L −1 KOH and 0.5 mol L −1 urea as the fuel at a flow rate of 15 mL min −1 . Besides, when the human urine is directly fed as the fuel, direct urine-hydrogen peroxide fuel cell reaches a maximum power density of 7.5 mW cm −2 with an open circuit voltage of 0.80 V at 20 °C, showing a good application prospect in wastewater treatment. [ABSTRACT FROM AUTHOR]

In this paper, the graphene oxide nanosheets are simultaneously reduced and deposited on nickel foam (denoted as Ni-foam@GNS) by one step electrodeposition method. The interconnected crumpled graphene nanosheets grown on Ni foam serve as a three-dimensional (3D) conductive skeleton for hydrothermal deposition of MnO 2 nanosheets by in-situ redox reaction. The MnO 2 nanosheets anchored on the graphene covered nickel foam (denoted as Ni-foam@GNS@MnO 2 ) show unique 3D porous interconnected networks. The samples are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), N 2 adsorption–desorption measurements and fourier transform infrared spectroscopy (FT-IR). The capacitive performances are researched by cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). The results reveal that the Ni-foam@GNS@MnO 2 electrode exhibits a high specific capacitance of 462 F g −1 at 0.5 A g −1 and excellent capacitance retention of 93.1% after 5000 cycles at 10 A g −1 . Furthermore, the Ni-foam@GNS@MnO 2 electrode delivers a high energy density of 26.1 Wh kg −1 even at a high power density of 3981 W kg −1 . These results demonstrate that the Ni-foam@GNS@MnO 2 composite offers great promise in large-scale energy storage device applications. [ABSTRACT FROM AUTHOR]

A novel and binder free Co@graphite/paper electrode is prepared by electrodeposition Co nano-sheet on the surface of a graphite layer modified paper substrate. The morphology and phase structure of the Co@graphite/paper electrode are characterized by scanning electron microscopy equipped with energy dispersive X-ray spectrometer, transmission electron microscope and X-ray diffractometer. The catalytic activity of the Co@graphite/paper electrode for H 2 O 2 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The catalyst combines tightly with the paper and exhibits a good stability. The oxidation current density reaches to 580 mA cm −2 in 2 mol dm −3 NaOH and 0.5 mol dm −3 H 2 O 2 at 0.5 V. Besides, we illustrate the reaction mechanization of the H 2 O 2 electrooxidation on the Co film. [ABSTRACT FROM AUTHOR]

[Display omitted] • OMC@NiO/Ni is synthesized via solvothermal reaction and subsequent calcination treatment. • "Trunk-leaf vein" structure endows OMC@NiO/Ni with superior electrochemical performance. • An asymmetric supercapacitor based on OMC@NiO/Ni and rGO/VO x as positive and negative electrodes respectively, is assembled. Supercapacitors are sustainable energy storage devices with the characteristics of high power density, long life span and ultrafast charge-discharge time. Herein, considering low conductivity of NiO and inspired by the "trunk-leaf vein" structure, mesoporous carbon and nickel dots are introduced into structure reacting as electron scaffold via facile hydrothermal and annealing procedures. Special hierarchical structure is obtained with oxygen modified mesoporous carbon (OMC) as core and NiO sheets as core accompanying with metallic nickel dots deposited on NiO sheets. Such "trunk-leaf vein" architecture can effectively ensure more active sites contacting with electrolyte, furthermore provide conductive scaffolds for electron transport. As expected, the OMC@NiO/Ni exhibits high specific capacitance of 651.3 F g−1 at 2 A g−1 and superior cycling life of 92.2% after 4000 cycles. Moreover, a novel negative electrode rGO/VO x is synthesized ascribe to the superior capacitance and life span. At last, an asymmetric device is assembled using OMC@NiO/Ni as positive electrode and rGO/VO x as negative electrode, which delivers maximum energy density of 44.3 Wh kg−1, high power density of 12,000 W kg−1 and excellent cycling life of 94.5% after 5000 cycles. The high performance of OMC@NiO/Ni renders it a potential material for energy storage-conversion equipments. [ABSTRACT FROM AUTHOR]

Summary: Doping Mn element into host material is an efficient approach to enhance the specific capacitance and cycling stability of supercapacitor. In this aspect, we fabricate Co‐Mn LDHs (CMLs) hollow polyhedron generated from ZIF‐67 via a template sacrifice method. Controllable doping of Mn element with gradient contents on the effect of electrochemical performance are investigated in detail. Moreover, in order to assemble a hybrid supercapacitor with superior energy and power output, a negative electrode based on MXene/rGO/V10O24 is synthesized considering the integration of EDLC and pseudocapacitance. As expected, the asymmetric supercapacitor of CMLs‐0.53//MXene/rGO/V10O24 delivers high energy density of 44.4 Wh kg−1, maximum power density of 12 750 W kg−1 and superior cycling life (91.6% capacitance retention after cycling 10 000 cycles). The special idea on the construction of CMLs with hollow structure can offer new insight to resolve the complicated steps during preparation procedure. The results also indicated that the device based on CMLs‐0.53 and MXene/rGO/V10O24 is a good candidate in the utilization of energy storage and conversion system in the future. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries (ZIBs) hold significant promise for large‐scale energy storage. While considerable strides have been made in modifying separators, the challenge of developing dendrite‐free, corrosion‐resistant, and cost‐effective separators for achieving extended cycling performance of Zn anodes persists. In light of this, a TiO2 coating separator to mitigate interfacial corrosion and passivation reactions, thereby facilitating high‐performance ZIBs is designed. This study delves into the influence of the loading amount and crystal phase of the TiO2 coating layers on separator modification. Zn symmetric cells employing the anatase TiO2‐modified glass fiber (A‐TiO2@GF) separator demonstrate superior Zn2+ ion transport kinetics in a mild ZnSO4 electrolyte, ensuring sustained long‐term stability and uniform Zn deposition. Furthermore, the reduced hydrogen evolution reaction (HER) activity of A‐TiO2 coatings curbs H+ ion migration, minimizing interfacial corrosion and HER. Consequently, the assembled Zn||CaV8O20 zinc‐ion full cells demonstrate outstanding long‐term durability and impressive specific capacity, boasting a discharge capacity of 142 mAh g−1 after 1000 cycles. This work introduces a straightforward interface engineering strategy for creating efficient separators in zinc‐ion batteries, promoting uniform Zn deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] In this paper, we have developed a simple and efficient sulfur-amine chemistry strategy to prepare a three-dimensional (3D) porous Ti 3 C 2 T x composite with large amounts of N and S terminal groups. The well-designed 3D macroporous architecture presents enlarged interlayer spacing, large specific surface area, and unique porous structure, which successfully solves the re-stacking issue of MXene during storage and electrode fabrication. It is the amount of concentrated hydrochloric acid added to the S-EDA (ethylenediamine)/MXene colloidal suspension that is critical to the formation of 3D morphology. In addition, N and S terminals on MXene could improve the adsorption ability of K+. Owing to the synergistic effect of the structure design and terminal modification, the N, S codoped three-dimensional porous Ti 3 C 2 T x (3D-NSPM) material shows a high surface capacitive contribution and rapid diffusion kinetics for K+ and Na+. As a result, the as-prepared 3D-NSPM delivers high reversible capacity (237 and 273 mAh g−1 at 0.1 A g−1 for PIBs and SIBs, respectively), superb cycling stability (84.9% capacity retention after 10,000 cycles at 1 A g−1 in PIBs and 74.0% capacity retention after 2200 cycles at 1 A g−1 in SIBs), and excellent rate capability (111 and 196 mAh g−1 at 5 A g−1 for PIBs and SIBs, respectively), which are superior to other MXene-based anodes for PIBs and SIBs. Moreover, the described strategy provides a new insight for constructing the 3D porous structure from 2D building blocks beyond MXene. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) have stimulated extensive attention due to their environmental friendliness and low cost. Unfortunately, the inevitable dendrite growth and corrosion on the zinc (Zn) anode severely hinder the practical application of AZIBs. Herein, an amino acid containing an imidazole group is introduced as an effective additive to address these issues. The dynamic conversion of amino acid and protonated amino acid creates a pH buffer function that regulates solution pH in real time, inhibits hydrogen evolution reaction (HER), and eliminates notorious by‐products. In addition, the protonated amino acid is preferentially adsorbed on the Zn anode, preventing contact of the active water with the Zn surface and promoting homogeneous Zn deposition. Thus, the amino acid‐based electrolyte promotes dendrite free plating/stripping with a Coulombic efficiency up to 99.67% and cycle lifetime of 2600 h. In particular, a depth of discharge of up to 87% can be achieved with an ultra‐high areal capacity of 24 mAh cm−2. The developed Zn||CVO full cell also exhibits better electrochemical performance than that without additives. This work provides an effective and convenient approach for safe and efficient Zn‐ion batteries. [ABSTRACT FROM AUTHOR]

The synergy between iron doping and (1 1 1) facet engineering in Fe-NiSe octahedron reinforces catalytic activity for IRR to yield impressive photovoltaic performance of DSSCs. [Display omitted] • The possibility of Fe-NiSe (1 1 1) as CE catalysts was investigated by DFT calculation. • The well-defined Fe-doped NiSe octahedron with (1 1 1) plane was synthesized. • Synergy between doping and facet engineering reinforces electrochemical behavior. • PCE can be further enhanced by introducing Fe heteroatom into NiSe (1 1 1). Reasonable design of cost-effective counter electrode (CE) catalysts for triiodide (I 3 −) reduction reaction (IRR) by simultaneously combining heteroatom doping and facet engineering is highly desired in iodine-based dye-sensitized solar cells (DSSCs), but really challenging. Herein, the density function theory (DFT) calculations were first conducted to demonstrate that the Fe-doped NiSe (1 1 1) showed an appropriate adsorption energy for I 3 −, increased number of metal active sites, reinforced charge-transfer ability, and strong interaction between 3 d states of metal sites and 5 p state of I 1 atoms in I 3 −, compared to NiSe (1 1 1). Based on this finding, the well-defined Fe-NiSe octahedron with exposed (1 1 1) plane (marked as Fe-NiSe (1 1 1)) and NiSe octahedron with the same exposed plane (named as NiSe (1 1 1)) are controllably synthesized. When the as-prepared Fe-NiSe (1 1 1) and NiSe (1 1 1) worked as CE catalysts, Fe-NiSe (1 1 1) exhibits improved electrochemical performance with higher power conversion efficiency (PCE) than NiSe (1 1 1), providing new opportunity to replace precious Pt for DSSCs. [ABSTRACT FROM AUTHOR]

To improve the complexity and low catalytic performance and reduce the high cost of the traditional electrode preparation process for the sodium borohydride electro-oxidation reaction (BOR), in this work, a self-supported and efficient electrode material grown on nickel foam (CoNi/Co3O4/NF) was successfully designed using a simple hydrothermal synthesis method accompanied by the electrodeposition process. Benefiting from the three-dimensional nanoarray structure of CoNi/Co3O4/NF and the uniform distribution of Co and Ni modulating active sites by electrodeposition, the catalytic activity towards NaBH4 exhibits high efficiency. CoNi/Co3O4 exhibits excellent catalytic performance (up to 2157 mA cm−2 in 2 mol L−1 NaOH and 0.3 mol L−1 NaBH4), a high electrochemically active surface area (62.5 cm−2), and a low activation energy (15.56 kJ mol−1). The CoNi/Co3O4/NF electrode was further investigated on a direct sodium borohydride–hydrogen peroxide fuel cell (DBHPFC), which exhibited a maximum power density of 108.5 mW cm−2 and excellent stability. The excellent performance is mainly due to its unique nanoarray structure and electrodeposition distribution of Co and Ni active sites, which increases the electrochemical surface area and enhances the contact between the electrode and the electrolyte. [ABSTRACT FROM AUTHOR]

In this study, Acacia catechu (AC) extract was used as a stabilizing and reducing agent to synthesize silver (Ag) and titanium dioxide (TiO 2) nanoparticles (NPs). By using AC extract, the synthesis process becomes more environmental friendly, economical, and advantageous. The morphology and size of synthesized Ag and TiO 2 NPs were determined by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Dynamic light scattering (DLS), Atomic force microscopy (AFM), and Scanning electron microscopy (SEM). Elemental composition was determined by using Fourier transform infrared spectroscopy (FTIR) and Energy dispersive X-ray spectrometer (EDX), EDS mapping and X-ray photoelectron spectroscopy (XPS). The observations from TEM, SEM, AFM, and DLS revealed that synthesized products are spherical, hexagonal, polydispersed, and ranged within 6–20 nm size. XRD result demonstrated well crystallized and smaller size NPs are formed in both cases. FTIR and XPS analysis depicted the presence of flavonoids, terpenoids, and amino groups in addition to benzene ring agents; which act as stabilizing agents as well as possible aromatic primary amine groups may also be attached with the surface of Ag and TiO 2 NPs. Furthermore, the synthesized AgNPs exhibited strong antibacterial activity against S-aureus and catalytic application over Rose Bengal, Rhodamine B, and 4 nitrophenol dyes as compared to TiO 2 under sunlight (solar irradiation). Overall, Ag and TiO 2 NPs exhibit high potential in the development of antibacterial materials for both Gram-positive as well as Gram-negative bacteria and catalytic material for photocatalytic degradation of a certain type of hazardous dyes or chemicals, thereby paving the way for the treatment and bioremediations. The reason could be high energy and smaller size particles were active in the photo-catalysis and antibacterial performance of AgNPs compared to TiO 2 NPs. Unlabelled Image • Ag and TiO 2 nanoparticles (NPs) were synthesized by green synthesis method using extract of Acacia catechu. • XRD, XPS spectra analysis and DLS revealed the confirmation of the Ag and TiO 2 NPs. • SEM and TEM revealed spherical and poly-dispersed particles. • ZETA potential revealed that well stabilized Ag and TiO 2 NPs. • Ag and TiO 2 NPs successfully degraded carcinogenic chemicals and have antibacterial potential against S-Aureus. [ABSTRACT FROM AUTHOR]

The need for safe, cost-effective aqueous magnesium ion batteries has led to high electrochemical performance designs of materials and structures to meet strict requirements. A composite of manganese dioxide and carbon molecular sieves (δ -MnO 2 @CMS) with a core-shell structure is used as the cathode in the aqueous magnesium ion battery, which not only solves the inherent deficiencies of low conductivity from manganese dioxide but also maximizes its specific capacities via a hierarchical structure. In addition, the anode material, nanowire VO 2 (formed via a solvothermal reaction) is rarely investigated in this system. Interestingly, this material can form new electrodes with more stable structures after the first charged process and avoids the formation of MgO, thereby providing insertion/extraction of magnesium ions into/from the host anode material. An aqueous rechargeable magnesium ion battery can be successfully assembled using the two electrodes designed above. This device shows high rate properties and delivers reversible capacities of 112.2, 94.6, 78.7, 69.5, and 59.1 mAh g−1 at current densities of 50, 100, 200, 300, and 500 mA g−1. Image 1 • δ -MnO 2 @CMS with core-shell structure is synthesized by hydrothermal method. • The nanowire VO 2 as anode is obtained by simple one-step hydrothermal process. • The Mg2+ insertion/deinsertion mechanism of two electrodes is explored. • Assembled aqueous magnesium-ion battery exhibits excellent rate property. [ABSTRACT FROM AUTHOR]

The borohydride oxidation reaction (BOR) is the main reaction in the anode of direct borohydride fuel cells (DBFCs), which is also fundamental to highlight the advantages of DBFCs. However, the catalysis of BOR still faces many challenges. On the one hand, further breakthroughs in catalytic activity are sought to achieve high performance of the anode; on the other hand, the negative effects brought by the side reactions, including the bubble effect, loss of fuel utilization, poisoning of the catalyst, etc., are urgently needed to be mitigated. Essentially, the running of the anode is the catalysis of BOR, so the catalytic viewpoint is critical to solving the above problem. In this work, an updated review of the effects of electrode design and the modulation of the catalytic environment on the anode is provided. Specifically, the electrode design is reviewed mainly from the perspective of catalytic activity, selectivity, and protective strategies. Besides, the modulation of the catalytic environment is emphasized in the systematic configuration and reactant transfer engineering. This work is expected to provide an in-depth understanding of the catalysis of BOR and afford significant inspiration toward the design of the anode. In this work, an updated review of the effects of electrode design and the modulation of the catalytic environment on the anode of direct borohydride fuel cells is provided. [Display omitted] • Based on a catalytic perspective DBFC anodes were reviewed. • Engineering strategies for electrode design are summarized. • The effects of catalytic environmental on the anode are discussed. • Challenges and outlooks for the design of DBFC anodes are provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • The carbonized recycled melamine sponge obtained excellent low-cost porous matrix. • FeNi@NCS shows lower reaction potential and higher electron transfer ability on UOR. • Successfully assembled the DBHPFC using urine as fuel. • DUHPFC presents excellent open circuit voltage. The direct urea fuel cell (DUFC) is a power generation equipment with urea-rich wastewater or urine as fuel source. It has the unique ability to purify sewage while simultaneously generating electricity, making it a highly efficient and environmentally friendly option. In this paper, pomegranate seed-like Ni nano-blocks and Fe nanosheets were synthesized by electrodeposition and chemical reduction and attached to the carbonized melamine sponge matrix. The N -doped carbon sponge (NCS) provided a large number of polyhedral holes, which allowed for efficient gas escape through channels. The combination of Fe reduces the initial urea oxidation potential, reaction activation energy and reaction resistance. The synthesized FeNi supported on N -doped carbon sponge composite (FeNi@NCS) has a catalytic current density of 625 mA cm−2 and a Tafel slope of 42.51 mV dec−1 for urea electrooxidation reaction (UOR). Assembling the direct urine-hydrogen peroxide fuel cell (DUrHPFC) resulted in the highest performance output. The open circuit voltage (OCV) was 0.98 V, and the peak power density reached 9.61 mW cm−2. The results show that the prepared catalyst provides an opportunity to solve the problems that hinder the development of urea green cycle at present. [ABSTRACT FROM AUTHOR]

[Display omitted] MoS 2 is regarded as a hopeful anode candidate for sodium-ion batteries (SIBs) due to their various merits such as high specific capacity, abundant raw material reserves and low cost. However, their practical application is impeded by unsatisfied cycling ability due to the intense mechanical stress and unstable solid electrolyte interphase (SEI) during Na+ insertion/extraction process. Herein, spherical MoS 2 @polydopamine derived highly conductive N -doped carbon (NC) shell composites (MoS 2 @NC) are designed and synthesized to promote the cycling stability. The internal MoS 2 core is optimized and restructured from the original micron-sized block to the ultra-fine nanosheets during initial 100–200 cycles, which not only improves the utilization of electrode materials but also shortens the ion transport distance. The outer flexible NC shell effectively maintains the original spherical structure of the overall electrode material and prevents the occurrence of large-scale agglomeration, which is conducive to form a stable SEI layer. Therefore, the core–shell MoS 2 @NC electrode presents a remarkable cyclic stability and a capable rate performance. Under a high rate of 20 A g−1, the high capacity of 428 mAh g−1 can be acquired after over ultra-long 10,000 cycles without obvious capacity loss. Moreover, the MoS 2 @NC‖Na 3 V 2 (PO 4) 3 full-cell assembled by employing commercial Na 3 V 2 (PO 4) 3 cathode can achieve a high capacity retention of 91.4% after 250 cycles at 0.4 A g−1. This work reveals the promising prospect of MoS 2 -based materials as anode of SIBs, and also has some inspirations on the structural design for conversion-type electrode materials. [ABSTRACT FROM AUTHOR]

As post‐lithium ion batteries, both sodium‐ion batteries (SIBs) and potassium ion batteries (PIBs) possess great potential for large scale energy storage. However, the application of both SIBs and PIBs are hindered by the lack of suitable electrode materials. Here, we synthesized the sulfur decorated Ti3C2Tx (S−T3C2Tx) MXene as electrode material for SIBs and PIBs. Thanks to the sulfur functional group and the formation of Ti−S bond, which facilitates the sodium in‐/desertion and strengthens the potassium ion adsorption ability, as well as enhances ion reaction kinetics and improved structure stability, the S−T3C2Tx exhibit excellent sodium/potassium storage performance, high reversible capacities of 151 and 101 mAh g−1 at 0.1 mA g−1 were achieved for SIBs and PIBs, respectively. Moreover, the S−T3C2Tx exhibits remarkable long‐term capacity stability at a high density of 500 mA g−1, providing an impressive storage of 88 mAh g−1 for SIBs and 41 mAh g−1 for PIBs even after 2000 cycles. This work could give a deep comprehension of the heteroatom modification influence on the MXene‐based framework and promote the application of MXene electrodes. [ABSTRACT FROM AUTHOR]

Organic polymers have been considered reliable candidates for lithium storage due to their high capacity and lack of volume expansion. Compared with other organic polymers, polyimide has become a very promising electrode material for lithium‐ion batteries (LIBs) because of its easy synthesis, customizable structure and structural stability. A large number of studies have confirmed that the benzene ring structure of polyimide has strong lithium storage capacity as an anode material. Hence, we designed and synthesized polyimide organic polymer (PBPAQ) for the first time. The unique spherical flower structure of this material enhances the interaction between the electrode material and the electrolyte by increasing the contact area. The PBPAQ anode has a specific discharge capacity of 738 mAh g−1 after 100 cycles at 0.1 A g−1. The excellent lithium storage performance of this material laid a foundation for the research of the anode of LIBs in the future. [ABSTRACT FROM AUTHOR]

Binders play a critical role in rechargeable lithium‐ion batteries (LIBs) by holding granular electrode materials, conductive carbons, and current collectors firmly together to form and maintain a continuous electron conduction phase with sufficient mechanical strength. In the commercial LIBs, the dominant binder is polyvinylidene fluoride for the cathode (LiCoO2, LiFePO4, LiNixCotyMnzO2, etc.) and carboxyl methylcellulose/styrene‐butadiene rubber for the anode (graphite and Li4Ti5O12). However, these polymer binders have several drawbacks, particularly, a lack of electronic and lithium‐ion conductivities. Here, a novel organic/inorganic hybrid conductive binder (LAP‐rGO) for both the anode and cathode of LIBs is reported. The binder consists of 2D reduced graphene oxide sheets with anchored long alkane chains. Electrodes prepared using this binder exhibit sufficient high bond strength, fast electrolyte diffusion, high rate charge/discharge performance, and excellent cycling stability. Around 130 mAh g−1 capacity enhancement at 5C is demonstrated for LiFePO4 and Li4Ti5O12 electrodes owing to the combined improvement in electron and lithium ion transportation. LAP‐rGO bond graphite anode shows specific capacity beyond its theoretical value. Electrode slurries prepared using this new binder have superior processing and coating properties that can be prepared under a high humidity and dried using less energy. [ABSTRACT FROM AUTHOR]

To relieve the overwhelming pressure on fossil energy, aqueous magnesium ion batteries attracted tremendous attention owing to their low cost and high safety. However, the cathode materials are apt to occur lattice distortion because of the electrostatic interaction between magnesium ions and crystal. The 2×2 manganese octahedral molecular sieve with potassium ions and water located in the tunnels (K‐OMS‐2), utilized as a cathode material for chargeable magnesium ions batteries, is exposed to irreversible Mg2+ intercalation/deintercalation due to lattice distortion, which heavily damages the electrochemical properties and declines the capacity. Herein, we carry out an ion doping strategy to overcome the above issues, leading to an enhanced Mg Mg2+ storage behavior. The Nb or V cation is successfully doped into K‐OMS‐2 by a facile reflux method under room temperature. The specific surface area is enlarged by the addition of cations, which promise a large electrode‐electrolyte contact area. The Nb and V doped K‐OMS‐2 present a capacity of 252.6 and 265.9 mAh/g at 20 mA/g, respectively. This work demonstrates an ion doping approach toward exploiting the stable and high‐capacity Mg‐ion battery cathode and provides potential cathode materials for a large‐scale aqueous Mg‐ion‐based energy storage system. [ABSTRACT FROM AUTHOR]

The adoption of effective, minimal, and versatile electrocatalysts for water splitting to generate hydrogen fuels is of critical importance. The bulk of newly described materials have considerable onset potential, but their electrocatalytic activity is limited by weak electrical conductivity and a limited range of catalytic sites. The combination of a few precious metals added with transition metal-based compounds is a novel and captivating approach. Herein, cobalt ferrite oxide (Co 2 FeO 4) @ palladium oxide (PdO) nanostructures have been prepared through the combined use of hydrothermal and ultraviolet (UV) irradiation techniques. For hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics, the modified composition offers a high concentration of active sites, improved electrical conductivity, and stability. The Co, Fe, and Pd ions at the composite system's interface may affect the adsorption energy of reaction intermediates synergistically, enabling the process to continue with less potential. The electrocatalyst Co 2 FeO 4 @PdO demonstrates an excellent bifunctional approach to electrochemical water splitting (EWS) for HER and OER in alkaline medium. As-prepared electrocatalyst shows an overpotential value of 269 and 259 mV for HER and OER at 10 and 20 mA/cm2 current densities respectively. The low charge transfer resistance values such as 72.2 and 62.4 Ω and durability for 48 h has been observed toward HER and OER , support this material as an efficient and durable electrocatalyst for energy conversion systems. [Display omitted] • Effective Cobalt–Iron-Ferrite oxides and Palladium-oxide based bifunctional electrocatalyst. • Promising activity for HER and OER with lower Tafel slope values in the alkaline media. • Longer stability and durability for 20 h. [ABSTRACT FROM AUTHOR]

A binder-free and flexible Au electrode is prepared by spontaneous deposition of Au onto a A4 (A4-paper)-8B (8B pencil)-Ni Film substrate (ABNi) which is assembled by electrodeposition of nanoscale Ni particles on the surface of A4 paper coated by 8B pencil. The morphology and phase structure of the (A4-paper)-8B (8B pencil)-Ni Film-Au (ABNiAu) electrode are characterized by scanning electron microscopy equipped with energy dispersive X-ray spectrometer and X-ray diffractometer. The catalytic activity of the ABNiAu electrode for NaBH 4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The electrode exhibits a high electric conductivity and the activity substance attaches to the surface of paper substrate tightly and does not fall off at all and the nanoscale Ni and Ni Au alloy enhance the broken of the B H bond in the BH 4 − , all of which lead to a high catalytic activity for NaBH 4 electrooxidation. The oxidation current density reaches 300 mA cm −2 in 1 mol dm −3 NaOH and 0.1 mol dm −3 NaBH 4 at −0.2 V. The exchanged electrons (n) is 6.0 (8.0 in theory), which indicates that the ABNiAu electrode has much higher utilization efficiency of the fuel than our reported LaNi 5 /Pd (n = 4) electrode. [ABSTRACT FROM AUTHOR]

In order to alleviate the energy crisis and propel a low-carbon economy, hydrogen (H2) plays an important role as a renewable cleaning resource. To break the hydrogen evolution reaction (HER) bottleneck, we need high-efficiency electrocatalysts. Based on the synergistic effect between bimetallic oxides, hierarchical mesoporous CoNiO2 nanosheets can be fabricated. Combining physical representations with electrochemical measurements, the resultant CoNiO2 catalysts present the hierarchical microflowers morphology assembled by mesoporous nanosheets. The ultrathin two-dimensional nanosheets and porous surface characteristics provide the vast channels for electrolyte injection, thus endowing CoNiO2 the outstanding HER performance. The excellent performance with a fewer onset potential of 94 mV, a smaller overpotential at 10 mA cm−2, a lower Tafel slope of 109 mV dec−1 and better stability after 1000 cycles makes CoNiO2 better than that of metallic Co and metallic Ni. [ABSTRACT FROM AUTHOR]

[Display omitted] Exploring capable and universal electrode materials could promote the development of alkalis (Li, Na, K) ion batteries. 2D MXene material is an ideal host for the alkalis (Li, Na, K) ion storage, but its electrochemical performance is limited by serious re-stacking and aggregation problems. Herein, we cleverly combined electrostatic self-assembly with gas-phase vulcanization method to successfully combine Ti 3 C 2 T x -MXene with ultra-long recyclability and high conductivity with MnS, which presents high specific capacity but poor conductivity. The as-prepared 3D hierarchical Ti 3 C 2 T x /MnS composites have an unique sandwich-like constituent units. The tiny MnS nanoparticles are restricted between the Ti 3 C 2 T x layers and play a key role in expanding the Ti 3 C 2 T x interlayer spacing. As a result, the 3D Ti 3 C 2 T x /MnS composites as the anode of LIBs exhibits a superior capacities of 826 and 634 mAh/g after 1000 and 3000 cycles at 0.5 and 1.0 A/g, respectively. More importantly, we reveal the reaction mechanism that the specific capacity first increases and then gradually stabilizes with the increase of charge and discharge cycle times when the as-prepared 3D Ti 3 C 2 T x /MnS was used as the anode of LIBs. In addition, we have also used this material in SIBs and PIBs and achieved remarkable electrochemical capability, with a specific capacity of 107 mAh/g after 2500 cycles at 0.5 A/g or 127 mAh/g after the 2000th cycle at 0.2 A/g, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • LiCoO 2 powder leaching was achieved by microwave via deep eutectic solvent. • Two kinds of deep eutectic solvents were used in this microwave-ultra-fast leaching. • Over 90 % of Li and Co were leached at 4 min and 160 W by adding urea / lactic acid. • Li and Co leaching were controlled by shrinking core model of chemical reaction. The large-scale use of electric vehicles produced massive discarded lithium-ion batteries, containing many recyclable valuable metals and toxic and harmful substances. Biodegradable and recyclable deep eutectic solvent (DES) is considered a green recycling technology for spent LIBs. Herein, we proposed a microwave-enhanced approach to shorten the leaching time in the urea/lactic acid: choline chloride: ethylene glycol DES system. The dipole moments induced by urea or lactic acid on LiCoO 2 surface increased over two orders of magnitude under the high electric field. Because of this, over 90 % of Li and Co can be fast leached at 4 min and 160 W in the urea/lactic acid: choline chloride: ethylene glycol DES system. Meanwhile, we established two models to explain the leaching mechanism of metal ions from their leaching kinetics and micro-level behavior, and named them dot-etching and layer-peeling processes, respectively. By further analyzing, we found that the dot-etching can be attributed to the synergistic effect of reduction and coordination, which caused the surface of leaching residues porous. The layer-peeling process depends on neutralization, and the leaching residues had a smooth surface in this process. This work highlights the effect of microwave-enhanced strategy and DES surface chemistry on spent electrode materials recovery. [ABSTRACT FROM AUTHOR]

MoSSe nanosheets anchored carbon tubes (CTs) were prepared with facile hydrothermal method and further selenized carbonization treatment. The hollow tubular carbon skeletons with abundant functional groups can regulate the uniform growth of MoS 2 clusters. In the subsequent step, the selenation treatment can extend the interlayer spacing of MoS 2 and form chemical bond (Mo N C) between the interface of MoSSe and CTs, which can effectively facilitate the transport of electron/ions. As the electrode materials for both SIBs and KIBs, the MoSSe@CTs presented a high and efficient Na+/K+ ions storage capability and good cycling stability. [Display omitted] • The tubular carbon skeletons expose abundant active sites for MoS 2 nanosheets growth. • The selenization treatment can expand the interlayer spacing of MoS 2 nanosheets. • The unique structure can improve rate capability and cycling stability of batteries. The structural stability and reaction kinetics of anodes are essential factors for high-performance battery systems. Herein, the molybdenum sulfide selenide (MoSSe) nanosheets anchored on carbon tubes (MoSSe@CTs) are synthesized by a facile hydrothermal method combining with further selenization/calcination treatment. The unique tubular carbon skeletons expose abundant active sites for the well-dispersed growth of MoS 2 ultrathin nanosheets on both sides of the tubular carbon skeleton. In addition, the further selenization treatment can expand the interlayer spacing of molybdenum sulfide (MoS 2) nanosheets and facilitate the fast sodium/potassium-ion transition and storage. When used in sodium-ion batteries (SIBs), MoSSe@CTs electrode delivers a specific capacity of 486 mAh g−1 at 1 A g−1 and retains a stable reversible capacity of 465 mAh g−1 after 1000 cycles, indicating its good cycling stability. For potassium-ion batteries (KIBs), the MoSSe@CTs composite shows a capacity of 352 mA hg−1 at 1 A g−1 and a good cycling stability (maintains at 272 mA hg−1 after 1000 cycles). This work shows informative guiding significance for exploring advanced electrode materials of sodium/potassium-ion batteries. [ABSTRACT FROM AUTHOR]

MoSSe nanosheets anchored carbon tubes (CTs) were prepared with facile hydrothermal method and further selenized carbonization treatment. The hollow tubular carbon skeletons with abundant functional groups can regulate the uniform growth of MoS 2 clusters. In the subsequent step, the selenation treatment can extend the interlayer spacing of MoS 2 and form chemical bond (Mo N C) between the interface of MoSSe and CTs, which can effectively facilitate the transport of electron/ions. As the electrode materials for both SIBs and KIBs, the MoSSe@CTs presented a high and efficient Na+/K+ ions storage capability and good cycling stability. [Display omitted] • The tubular carbon skeletons expose abundant active sites for MoS 2 nanosheets growth. • The selenization treatment can expand the interlayer spacing of MoS 2 nanosheets. • The unique structure can improve rate capability and cycling stability of batteries. The structural stability and reaction kinetics of anodes are essential factors for high-performance battery systems. Herein, the molybdenum sulfide selenide (MoSSe) nanosheets anchored on carbon tubes (MoSSe@CTs) are synthesized by a facile hydrothermal method combining with further selenization/calcination treatment. The unique tubular carbon skeletons expose abundant active sites for the well-dispersed growth of MoS 2 ultrathin nanosheets on both sides of the tubular carbon skeleton. In addition, the further selenization treatment can expand the interlayer spacing of molybdenum sulfide (MoS 2) nanosheets and facilitate the fast sodium/potassium-ion transition and storage. When used in sodium-ion batteries (SIBs), MoSSe@CTs electrode delivers a specific capacity of 486 mAh g−1 at 1 A g−1 and retains a stable reversible capacity of 465 mAh g−1 after 1000 cycles, indicating its good cycling stability. For potassium-ion batteries (KIBs), the MoSSe@CTs composite shows a capacity of 352 mA hg−1 at 1 A g−1 and a good cycling stability (maintains at 272 mA hg−1 after 1000 cycles). This work shows informative guiding significance for exploring advanced electrode materials of sodium/potassium-ion batteries. [ABSTRACT FROM AUTHOR]

A novel electrode of PdCu nanoparticles modified free-standing reduced graphene oxide (rGO) framework (PdCu@rGOF) is fabricated via electrodeposition and chemical reduction and employed to the direct sodium borohydride-hydrogen peroxide fuel cell (DBHPFC). The resultant catalyst reveals excellent catalytic performance towards hydrogen peroxide (H 2 O 2) electroreduction reaction (HPRR) and sodium borohydride (NaBH 4) electrooxidation reaction (BOR) along with low activation energy (E a). Numerically, the PdCu@rGOF electrode delivers an HPRR current density of 455.2 mA cm−2 at 0 V (2 mol L−1 H 2 SO 4 +1.3 mol L−1 H 2 O 2). Additionally, the current density of BOR reaches up to 1065.3 mA cm−2 at 0 V for 2 mol L−1 NaOH and 0.3 mol L−1 NaBH 4. Meanwhile, the mechanism studies show that HPRR and BOR catalyzed by PdCu@rGOF mainly relates 2-electron-transfer process and quasi-8-electron-transfer process, respectively. Subsequently, PdCu@rGOF is assembled into a fuel cell, yielding the optimal power density of 188.9 mW cm−2. The open circuit potential (OCP) of DBHPFC is about 1.70 V at 293.15 K. The superior electrochemical performance of the optimized electrode can be attributed to the distinctive architecture and the strong adsorption and bond-breaking ability of Pd nanoparticles. This work indicates that the as-prepared PdCu@rGOF can be a promising catalyst for DBHPFC. [Display omitted] • A novel 3D through-hole rGOF framework has been successfully prepared. • PdCu@rGOF displays an excellent catalytic performance for HPRR and BOR. • PdCu@rGOF can be applied to both anode and cathode of DBHPFC. • DBHPFC presents high power density and operation stability. [ABSTRACT FROM AUTHOR]

[Display omitted] Polymer materials containing C 6 rings and C O become promising electrode materials for high-performance lithium ion batteries (LIBs). However, the poor electronic conductivity severely restricts its further application. Herein, we design and construct a pyromellitic dianhydride anhydride anthraquinone/reduced graphene oxides (PMAQ/rGO-40) composite as an anode material for LIBs. The PMAQ is uniformly wrapped by conductive rGO nanosheets. The PMAQ/rGO-40 electrode without additional conductive agents displays a discharge capacity of 253 mAh g−1 over 3000 cycles under 2A g−1, which is higher than that of the PMAQ electrode with conductive agents. Meanwhile, a capacity of 196 mAh g−1 is achieved under 5A g−1. The enhanced cycling performance and rate ability are attributed to the rGO conductive network, which promotes electronic transport capability. In addition, the lithium ion storage mechanism and kinetics in the PMAQ/rGO-40 are investigated. The excellent electrochemical performance shows the potential application of the PMAQ/rGO composite anode material for high performance LIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] Rechargeable metal batteries such as non-aqueous Li metal batteries and aqueous Zn metal batteries have received increasing attention due to the benefits of the high-energy metal anode. However, the dendric growth on the metal anode extremely leads to restricted cycling performance and potential safety issues. Herein, the MXene-modified conductive framework (MCF) is designed and fabricated as a universal current collector of anode for non-aqueous Li metal batteries and aqueous Zn metal batteries to suppress the dendric Li and Zn growth. The MCF exhibits the merits of good lithiophilicity and zincophilicity, enables an easy Li/Zn nucleation process, and possesses high plating/stripping reversibility. After plating Li/Zn, MCF@Li and MCF@Zn realize a dendrite-free surface, facilitating Li/Zn plating/stripping kinetics. The MCF@Li and MCF@Zn symmetric cell shows a low overpotential of 13 mV at 1 mA cm−2 after 900 cycles and 64 mV at 5 mA cm−2 after 750 cycles (1 mAh cm−2), respectively. Furthermore, the non-aqueous MCF@Li||LiFePO 4 full cells and the aqueous MCF@Zn||active carbon capacitors are assembled and present stable cycling ability and improved rate performance with low polarization. This work provides a universal current collector strategy to meet the requirements of non-aqueous and aqueous metal anodes, which may inspire more designs for metal-based energy storage systems. [ABSTRACT FROM AUTHOR]

Development of efficient, low cost and multifunctional electrocatalysts for water splitting to harvest hydrogen fuels is a challenging task, but the combination of carbon materials with transition metal-based compounds is providing a unique and attractive strategy. Herein, composite systems based on cobalt ferrite oxide-reduced graphene oxide (Co 2 FeO 4) @(rGO) using simultaneous hydrothermal and chemical reduction methods have been prepared. The proposed study eliminates one step associated with the conversion of GO into rGO as it uses direct GO during the synthesis of cobalt ferrite oxide, consequently rGO based hybrid system is achieved in-situ significantly, the optimized Co 2 FeO 4 @rGO composite has revealed an outstanding multifunctional applications related to both oxygen evolution reaction (OER) and hydrogen counterpart (HER). Various metal oxidation states and oxygen vacancies at the surface of Co 2 FeO 4 @rGO composites guided the multifunctional surface properties. The optimized Co 2 FeO 4 @rGO composite presents excellent multifunctional properties with onset potential of 0.60 V for ORR, an overpotential of 240 mV at a 20 mAcm−2 for OER and 320 mV at a 10 mAcm−2 for HER respectively. Results revealed that these multifunctional properties of the optimized Co 2 FeO 4 @ rGO composite are associated with high electrical conductivity, high density of active sites, crystal defects, oxygen vacancies, and favorable electronic structure arisinng from the substitution of Fe for Co atoms in binary spinel oxide phase. These surface features synergistically uplifted the electrocatalytic properties of Co 2 FeO 4 @rGO composites. The multifunctional properties of the Co 2 FeO 4 @ rGO composite could be of high interest for its use in a wide range of applications in sustainable and renewable energy fields. Illustration of multifunctional surface properties of Co 2 FeO 4 @rGO composite. [Display omitted] • In situ rGO and cobalt ferrite oxide (Co 2 FeO 4 @rGO) composite is prepared. • The synthesized composite exhibited tri-functional water catalysis. • Composite shows an overpotential of 240 mV at a 20 mAcm−2 for OER. • A long term durability of 48 h was also demonstrated by composite material. [ABSTRACT FROM AUTHOR]

The non-uniform plating–stripping behaviours of Li metal anodes hinder the application of Li metal batteries. Here, a stable 3D matrix is designed by coating a carbon skeleton with MXene, and the significant influence of the crystallographic texture of Li metal on electrochemical behaviour is investigated. The results demonstrate that the 3D MXene/carbon skeleton can effectively induce the evolution of advantageous Li(110) facets with a dendrite-free anode interface. Consequently, the modified Li metal anodes deliver stable plating–stripping behaviours. [ABSTRACT FROM AUTHOR]

The rational design of efficient electrocatalysts for hydrogen peroxide electroreduction is essential to improve the performance of direct hydrogen peroxide fuel cells. In this study, we synthesized a Co 4 N/CoNC with a heterogeneous interface grown directly on nickel foam (NF) substrates as a highly active electrocatalyst for hydrogen peroxide (H 2 O 2) electroreduction (HPRR). Benefiting from the integrated three-dimensional structure with sufficient active sites, the high electrical conductivity, and the synergistic effect of the heterogeneous interfaces of Co 4 N and Co–N–C, the electrode provides superior H 2 O 2 electrocatalytic properties, with a current density up to 0.65 A cm−2 at −0.8 V vs. Ag/AgCl, Tafel slope at 34.86 mV dec−1 and low activation energy as 9.65 kJ mol−1 in alkaline medium. Our findings provide insights into the design of efficient H 2 O 2 electrocatalyst design. [Display omitted] • Co 4 N/CoNC heterointerface catalysts synthesized by simple hydrothermal and co-precipitation methods. • The unique structure of Co 4 N/CoNC provides a large exposure of the heterogeneous interface to the reaction environment. • Co 4 N/CoNC exhibit excellent catalytic activity and stability in the electroreduction of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of efficient catalysts for hydrogen evolution reaction (HER) from water splitting is one of the most promising strategies to achieve the goal of peak carbon dioxide emissions and carbon neutrality. Herein, Ru nanoclusters decorated MoSe 2 nanosheets supported on a Crepis tectorum fluff biomass-derived hollow carbon tube (Ru-MoSe 2 /CMT) are prepared as the HER catalysts in both alkaline and acidic conditions. The Ru modification induces the transformation of MoSe 2 from 2H phase to 1T phase. Benefiting from the strong water dissociation ability of Ru, Ru-MoSe 2 /CMT exhibits a low overpotential of 70 mV with a Tafel slope of 39 mV dec-1 in 1 M KOH. Furthermore, the assembled Ru-MoSe 2 /CMT || RuO 2 system with a low cell voltage of 1.54 V at 10 mA cm−2 exhibits outstanding overall water splitting performance superior to Pt/C || RuO 2 system. The Ru-MoSe 2 /CMT || RuO 2 system also achieves the excellent stability of up to 30 h in 1 M KOH. The synergy effect between Ru and MoSe 2 , as well as the improved electron transfer kinetics provided by the biomass-derived carbon substrate together contribute to the excellent HER activity of Ru-MoSe 2 /CMT. [ABSTRACT FROM AUTHOR]

Formation of Mg(OH)2nanowires and their assemblies with sphere-shaped, echinus-shaped and nest-like micro-structures on a Mg-Li alloy surface was successfully demonstrated. Mg(OH)2nanowires were formed on the alloy surface via a self-growth process, after the alloy was electrooxidised in NaCl solution and the oxidation products were removed. The nanowires were characterised by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Infrared spectroscopy. The nanowires have hexagonal rod-like or brush-like morphology and are poorly crystallised. Pre-anodisation and the presence of Li in the alloy are key factors for the nanowire growth, which likely proceeds via a dissolution–precipitation mechanism. The roles of Li can be attributed to the prohibition of the formation of passivation film on the alloy surface and the acceleration of the formation of OH−anions through hydrogen-evolution reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • RuNi 1 Co 1 alloy nanoparticles embedded in the hollow carbon tubes with a mosaic structure was prepared. • The DFT calculations indicate that the addition of Ru could optimize the hydrogen adsorption free energy of Ni and Co sites. • RuNi 1 Co 1 @CMT exhibits considerable HER and OER activities, and a low cell voltage was required for the overall water splitting system. • RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system can be driven by a solar panel, which realized green and sustainable hydrogen production. The development of efficient bifunctional catalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for reducing the cost of hydrogen production by water splitting. Herein, hollow microtubes composed of RuNi 1 Co 1 alloy nanoparticles uniformly embedded in the carbon matrix (RuNi 1 Co 1 @CMT) are prepared through a simple impregnation followed by reduction. Benefiting from the unique mosaic structure and the synergistic effect between Ru and NiCo, RuNi 1 Co 1 @CMT achieves more exposed active sites and improved reaction kinetics. As a consequence, RuNi 1 Co 1 @CMT exhibits considerable catalytic activities with the overpotentials of 78 mV for HER and 299 mV for OER at 10 mA cm−2 in 1 M KOH. In addition, RuNi 1 Co 1 @CMT exhibits excellent stability for up to 30 h in both HER and OER processes at 20 mA cm−2, which is attributed to the protection of the RuNi 1 Co 1 alloy particles by the carbon layer. Furthermore, the assembled RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system shows a cell voltage of 1.58 V at 10 mA cm−2. The density functional theory (DFT) calculations indicate that the addition of Ru can optimize the hydrogen adsorption free energy of Ni and Co sites. Finally, a solar panel-driven water splitting device is built, which can realize green and sustainable hydrogen production. The fabrication of RuNi 1 Co 1 @CMT provides a new way for the preparation of effective alloy nanomaterials for energy storage and conversion. [ABSTRACT FROM AUTHOR]

As a recently emerging group of 2D materials, MXene has attracted extensive attention in the energy storage field in recent years owing to their outstanding features. However, the notorious issues of inevitable oxidation stability and surface‐to‐surface self‐restacking for MXene significantly prevent its further wide‐ranging application. Herein, the 3D macroporous oxidation‐resistant Ti3C2Tx MXene/graphene/carbon nanotube (MRC) hybrid hydrogels are prepared by a simple gelation method assisted by l‐cysteine as crosslinker and l‐ascorbic acid (VC) as reductant. Benefitting from the effectively alleviated restacking, excellent electrical conductivity, and the 3D inter‐crosslinked macroporous architecture, as a supercapacitor electrode, the obtained MRC aerogel exhibits a superior specific capacitance of 349 F g−1, unparalleled rate capability (52.0% at 3000 mV s−1) and amazing cyclic stability (retention of 97.1% after 100 000 cycles). Moreover, the 3D MRC‐30 aerogel exhibits an impressive oxidation‐resistant performance with just a 9.3% increase in electrical resistance after storing in ambient condition for 60 days, effectively alleviating the oxidation problem of MXene. This work demonstrates a new method for construction of 3D oxidation‐resistant MXene hydrogel, shedding new light on the promising applications of MXene materials, especially in high humidity and oxygen environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoSe 2 -MoSe 2 (1–1)/rGO has good HER activity in both acidic and alkaline media. • The CoSe 2 -MoSe 2 (1–1) nanosheets uniformly decorate the rGO matrix. • DFT results verify CoSe 2 -MoSe 2 (1–1) heterostructure owns small band gap and ΔG H*. • The rGO matrix and heterojunction structure improve the electronic conductivity. It is important to develop novel energy to solve energy shortage and environmental problems. Hydrogen evolution reaction (HER) is envisaged as a viable technology that can be used to develop sustainable clean energy. Herein, we report a catalyst with CoSe 2 -MoSe 2 heterostructure grown on reduced graphene oxide with an optimum Co/Mo proportion of 1:1 (CoSe 2 -MoSe 2 (1–1)/rGO). It exhibits good HER activities in both acidic and alkaline conditions. The CoSe 2 -MoSe 2 (1–1)/rGO shows an overpotential of 107 mV at 10 mA cm−2 with a Tafel slope of 56 mV dec−1 under acidic condition. Meanwhile, CoSe 2 -MoSe 2 (1–1)/rGO also presents an overpotential of 182 mV at 10 mA cm−2 and with a Tafel slope of 89 mV dec−1 under alkaline condition. These impressive performances of the catalyst are mainly due to the excellent electronic transmission capability of rGO and the abundant active sites of CoSe 2 -MoSe 2 heterostructure as well as the optimized hydrogen adsorption energy of CoSe 2 -MoSe 2 interface. The design of CoSe 2 -MoSe 2 (1–1)/rGO provides a meaningful guide for manufacturing electrode in energy storage and conversion. [ABSTRACT FROM AUTHOR]

• The CeS 2 incorporation modulates the internal electronic state. • Ce species stabilizes some of the surface sulphide against self-oxidation during OER process. • The strategy of iron dopant is conducive to induce plentiful S-defects. • The nanoparticles-rich structure affords ample holes and irregular flow channels. • Polyvalent Ce species provides great redox property, enhancing the electrocatalytic activity. Design and fabrication of high-efficiency nickel-rich electrocatalytic materials for sluggish oxygen evolution reaction (OER) remains a tremendous challenge. Modulating internal electronic state and accelerating charge transfer are two of vital means to optimizing electrocatalysts. In this work, nanoparticles-rich Fe-(CeS 2 /Ni 3 S 2) hybrid material with abundant heterointerfaces and sulfur-defects are facilely synthesized. The strategy of iron dopant is conducive to induce more sulfur defects. The cerium species can modulate the internal electronic state and stabilize some of the surface sulphide against self-oxidation during OER process. This self-supported heterogeneous material requires overpotentials of 254 and 372 mV to reach the current densities of 100 and 500 mA cm−2 in alkaline condition. The addition of urea or ethanol to the bath solution has been demonstrated as an efficient strategy for reducing the onset potential and decreasing energy consumption, thereby confirming the feasibility of applying this approach to energy-saving hydrogen production through electrolysis wastewater splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] • The composite was synthesized by a hydrothermal and vapor phase sulfidation method. • The hetrostruction and MXene improve the Na+ reaction kinetics. • The composite exhibits excellent rate and superior cycle stability. Molybdenum trioxide (MoO 3) is regarded as a promising material for rechargeable batteries attributed to its low cost, high theoretical capacity and eco-friendliness. Herein, N-doped carbon (NC) coated MoO 3 /MoS 2 composite decorated on MXene nanosheets (MoO 3 /MoS 2 /NC/MXene) has been synthesized by gas-phase vulcanization and coating of NC. The electrical conductivity and kinetics of ion diffusion/transport are greatly enhanced due to the vulcanization, NC coating and introduction of MXene. As a consequence, the composite exhibits high discharge capacity of 464 mAh/g at a current density of 0.1 A/g and still maintains a capacity of 202 mAh/g at a high current density of 5 A/g when used as the anode material for sodium-ion batteries. Furthermore, the electrode material still remains a high discharge capacity of 320 mAh/g with the capacity retention rate of nearly 100 % after 2000 cycles at a current density of 1 A/g. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defective graphene with high density of defects is prepared via Flash Joule Heating. • An ultrahigh reversible capacity of 2450 mAh g−1 is achieved for defective graphene. • Nascent defects, lithium plating and 3D structure contribute to the high capacity. • Excess lithium storage and fading mechanisms are revealed. • Insights for designing high-capacity electrodes based on defect engineering. Introducing defects is an effective approach to promote the lithium ion storage ability of host material. Constructing pure defects is beneficial to understand the lithium ion storage mechanism in the defects. Herein, we fabricate defective graphene without intricate functional groups via a flash Joule heating (FJH) technique within a mere 1 ms. The FJH-reduced graphene lattice harbors a multitude of defects, and its unique three-dimensional structural network enables an ultra-high lithium ion storage capacity. Moreover, the highest capacity of F-RGO-5 reaches 2500 mAh/g in the 800th cycle, its three-dimensional architecture allows it to withstand high currents and prolonged cycles without drastic failures. Nascent defects and defect-induced lithium plating predominantly contribute to capacity enhancement during cycling, while dendrite formation primarily leads to decay. Our findings present an approach to defect-based designs of high-capacity lithium anodes and provide valuable insights into their energy storage mechanisms. [ABSTRACT FROM AUTHOR]

The electrochemical nitrate reduction reaction (eNO 3 RR) to ammonia (NH 3) is a promising alternative method to the Haber-Bosch process that requires high temperature and pressure. In this contribution, the integrated Co 3 O 4 nanowire arrays on Ni foam (Co 3 O 4 /NF) are reported to exhibit the outstanding performance with a high NH 3 yield rate of 117.01 mg h−1cm−2, a superior NH 3 Faradaic efficiency of 99.28 %, a high effective current density of 1475.71 mA cm−2, and a good operation durability during 40 consecutive recycling tests (40 h) in 1.0 M NaOH (0.1 M NaNO 3). The high-valence metal cations as electron-deficient centers can act as Lewis-acid sites, favorably interacting with the Lewis base NO 3 −, and accordingly boosting the NO 3 − adsorption and activation. Moreover, the in-situ growth array configuration provides the substantial active sites and constructs a fast electron-transport channel, thus facilitating the conversion of NO 3 −-to-NH 3. Density functional theory (DFT) calculations also reveal that the Co atoms as the active sites are preferred to adsorb NO 3 −, implying that the NO 3 − electroreduction dominates the cathodic reaction rather than hydrogen evolution reaction. This study provides a viable method to design integrated electrodes with enhanced eNO 3 RR activity and selectivity, which might have broad prospects in the application of renewable energy. The efficient nitrate-to-ammonium conversion is achieved by the integrated Co 3 O 4 nanowire arrays rich in electron-deficient centers. Benefitted from the massive exposed active sites, improved conductivity and charge transfer efficiency, as well as the abundant Lewis acid sites, Co 3 O 4 nanowire arrays present the brilliant nitrate electroreduction performance, including 117.01 mg h−1 cm−2 NH 3 yield rate and 99.28 % Faradaic efficiency in 1.0 M NaOH with 0.1 M NO 3 −. [Display omitted] • High-valence metal cations are favorable to boost NO 3 − adsorption and activation. • Integrated nanowire arrays configuration can provide massive exposed active sites. • Co 3 O 4 /NF can provide a fast electron-transport channel and excellent conductivity. • Co 3 O 4 /NF presents the considerable activity and stability towards eNO 3 RR process. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeSe 2 -MoSe 2 (1-1)/rGO has good HER activity in both acidic and alkaline media. • FeSe 2 -MoSe 2 (1-1)/rGO has well stability in both acidic and alkaline media. • On the morphology, FeSe 2 -MoSe 2 nanoparticles uniformly decorate the rGO matrix. • DFT results verify the FeSe 2 -MoSe 2 (1-1)/rGO owns small work function. It is of great significance to develop inexpensive and high-efficiency electrocatalysts for the hydrogen evolution reaction (HER). In this work, we synthesized iron molybdenum selenide (FeSe 2 -MoSe 2) loaded on reduced graphene oxide (FeSe 2 -MoSe 2 /rGO) by a one-step hydrothermal method. We further optimized the Fe/Mo ratio and determined the best ratio to be 1-1. In acidic (or alkaline) solution, the optimized FeSe 2 -MoSe 2 (1-1)/rGO has a small Tafel slope of 55 (or 80) mV dec−1 and needs an overpotential of 101 (or 178) mV to achieve 10 mA cm−2. These good properties are mainly due to the structure of bimetallic selenides combining rGO. Moreover, rGO enhances the electrical conductivity. Furthermore, the synergistic effect between FeSe 2 -MoSe 2 (1-1) and rGO results in better HER performance. Density functional theory (DFT) calculation proves that FeSe 2 -MoSe 2 (1-1)/rGO has a small work function. Based on our reasonable design and analysis, FeSe 2 -MoSe 2 (1-1)/rGO is expected to be an efficient and robust catalyst for large-scale applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrocatalytic water splitting used for generating clean and sustainable hydrogen (H 2) can be very promising to address current energy shortage and associated environmental issues. However, this methodology is severely impeded by the tardy oxygen evolution reaction (OER). Hence, designing a preferable kinetics and thermodynamics oxidation reaction that supersede OER is very significant for the energy-saving production of H 2. Herein, hollow needle-like copper cobalt sulfide was constructed on carbon cloth (CuCo 2 S 4 /CC) as a bifunctional electrocatalyst to accelerate H 2 generation and simultaneously convert ethanol into value-added acetic acid. Thanks to the synergistic effect and unique structure of Cu and Co, CuCo 2 S 4 /CC displays superior catalytic activity and durability in ethanol oxidation reaction (EOR) with a low potential of 1.38 V vs. RHE (@10 mA cm−2). Meanwhile, it exhibits excellent hydrogen evolution reaction (HER) performance. The homemade CuCo 2 S 4 /CC//CuCo 2 S 4 /CC ethanol–water electrolyser only demands a voltage of 1.59 V to deliver 10 mA cm−2, 150 mV less than that used for ordinary water splitting. This shows that the ethanol–water electrolyser elaborated here holds encouraging potential in the energy-saving production of H 2 and oxidation of ethanol into value-added acetic acid. This present work may open the way for the rational design of other electrocatalysts for efficient biomass oxidation reaction and relevant H 2 production applications. [ABSTRACT FROM AUTHOR]

[Display omitted] MoS 2 is regarded as an attractive anode material for lithium-ion batteries due to its layered structure and high theoretical specific capacity. Its unsatisfied conductivity and the considerable volume change during the charge and discharge process, however, limits its rate performance and cycling stability. Herein, 3D tremella-like nitrogen-doped carbon encapsulated few-layer MoS 2 (MoS 2 @NC) hybrid is obtained via a unique strategy with simultaneously poly-dopamine carbonization, and molybdenum oxide specifies sulfurization. The three-dimensional porous nitrogen-doped carbon served both as a mechanical supporting structure for stabilization of few-layers MoS 2 and a good electron conductor. The MoS 2 @NC exhibits enhanced high rate performance with a specific capacity of 208.7 mAh g−1 at a current density of 10 A g−1 and stable cycling performance with a capacity retention rate of 85.7% after 1000 cycles at 2 A g−1. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO3) has recently aroused intensive interest as a renowned conversion‐type anode of Li‐ion batteries (LIBs). Nevertheless, the inferior rate capability, sluggish reaction kinetics, and fast capacity decay during a long‐term charge/discharge process seriously inhibits large‐scale commercial application. Herein, abundant oxygen vacancies and MXene nanosheets are elaborately introduced into MoO3 nanobelts through hydrazine reduction and electrostatic assembly to accelerate the ionic and electronic diffusion/transport kinetics for LIBs. Benefitting from the accelerated ion diffusion kinetics, enhanced electrical conductivity, and additional active sites induced by oxygen vacancies as well as the robust interfacial contact, the prepared MoO3−x/MXene heterostructure exhibits excellent lithium‐ion storage performances. First‐principles calculations indicate that the adsorption of Li+ ion and the electrical conductivity are significantly enhanced for the MoO3−x/MXene heterostructure. Thus, the composite exhibits high reversible capacity of 1258 mAh g−1 at 0.1 A g−1 for Li‐ion storage and retains 474 mAh g−1 at 10 A g−1, remarkably higher than those of the previously reported MoO3‐based anode materials. More importantly, the composite is fabricated with commercial LiFePO4 into a full LIB, which displays an unparalleled energy density of 330 Wh kg−1. [ABSTRACT FROM AUTHOR]

Potassium ion batteries or capacitors are a promising technology for large-scale energy storage due to the abundant resource and low cost of potassium. However, the development of stable electrode materials with high capacity, capable rate ability, and excellent cycling stability remains a challenge. Herein, carbon dots modified reduced graphene oxides (LAP-rGO-CDs) are designed and synthesized via a rapid and green microwave-assisted method with l -Ascorbic acid 6-palmitate (LAP) as the reducing agent. LAP-rGO-CDs present enlarged interlayer spacing and faster ion transfer rate owing to the introducing of carbon dots. Serving as a potassium ion battery electrode, LAP-rGO-CDs showed a high specific capacity of 299 mAh g−1 at 1 A g−1 and excellent cycling stability. Moreover, a LAP-rGO-CDs//AC full carbon-based potassium ion capacitor is assembled and displays a maximum energy density of 119 Wh kg−1 and a power density of 5352 W kg−1. This work demonstrates the potential application of LAP-rGO-CDs for high-performance potassium ion storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Integrating transition metal complexes with carbon-based materials, especially graphene, is a useful strategy for synthesizing effective hydrogen evolution catalysts. Herein, we report a design of hollow hexagonal NiSe–Ni 3 Se 2 nanosheets grown on reduced graphene oxide (NiSe–Ni 3 Se 2 /rGO) by a simple hydrothermal method as an effective catalyst for hydrogen evolution reaction (HER) in the full pH range. In 0.5 M H 2 SO 4 , the NiSe–Ni 3 Se 2 /rGO possesses 112 mV to achieve 10 mA cm−2 and a small Tafel slope (61 mV dec−1). In 1.0 M PBS and 1.0 M KOH, the overpotentials are 261 and 188 mV at 10 mA cm−2, and Tafel slopes are 103 and 92 mV dec−1, respectively. Meanwhile, it owns good cycle stability and durability over 20 h in the whole pH range (0-14). In all solutions, the HER performance of NiSe–Ni 3 Se 2 /rGO is better than that of NiSe–Ni 3 Se 2. This is because the rGO substrate accelerates the electron transfer and improves the electrical conductivity, increasing HER activity of catalyst. • The hollow hexagonal NiSe-Ni3Se2 nanosheets uniformly decorate the rGO. • The hollow structure exposes more active sites and transport pathways. • The hybrid material exhibits superior performance for HER in all pH media. • The stability of the composite is good under a variety of pH conditions. [ABSTRACT FROM AUTHOR]

2D MXene materials have attracted intensive attention in energy storage application. However, MXene usually undergoes serious face‐to‐face restacking and inferior stability, significantly preventing its further commercial application. Herein, to suppress the oxidation and self‐restacking of MXene, an efficient and fast self‐assembly route to prepare a 3D porous oxidation‐resistant MXene/graphene (PMG) composite with the assistance of an in situ sacrificial metallic zinc template is demonstrated. The self‐assembled 3D porous architecture can effectively prevent the oxidation of MXene layers with no evident variation in electrical conductivity in air at room temperature after two months, guaranteeing outstanding electrical conductivity and abundant electrochemical active sites accessible to electrolyte ions. Consequently, the PMG‐5 electrode possesses a striking specific capacitance of 393 F g−1, superb rate performance (32.7% at 10 V s−1), and outstanding cycling stability. Furthermore, the as‐assembled asymmetric supercapacitor possesses a pronounced energy density of 50.8 Wh kg−1 and remarkable cycling stability with a 4.3% deterioration of specific capacitance after 10 000 cycles. This work paves a new avenue to solve the two long‐standing significant challenges of MXene in the future. [ABSTRACT FROM AUTHOR]