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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]

Abstract: Hydrogen peroxide (H2O2) replaced oxygen (O2) as oxidant has been widely investigated due to its faster reduction kinetics, easier storage and handling than gaseous oxygen. The main challenge of using H2O2 as oxidant is the chemical decomposition. In this article, by using different C2H5OH/H2O volume ratio as the solvent, Co3O4 with different morphologies (nanosheet, nanowire, ultrafine nanowire net, nanobelts, and honeycomb-like) direct growth on Ni foam are synthesized via a simple solvothermal method for the first time. Results show that the introduction of ethanol could obviously improve the catalytic performance toward H2O2 electroreduction. The sample prepared in the solution with the C2H5OH/H2O volume ratio of 1:2 shows the best catalytic performance among the five samples and a current density of 0.214 A cm−2 is observed in 3.0 mol L−1 KOH + 0.5 mol L−1 H2O2 at −0.4 V (vs. Ag/AgCl KCl), which is much larger than that on the other metal oxides reported previously, almost comparable with the precious metals. This electrode of Co3O4 directly grown on Ni foam has superior mass transport property, which combining with its low-cost and facile preparation, make it a promising electrode for fuel cell using H2O2 as the oxidant. [Copyright &y& Elsevier]

Highlights: [•] β-Ni(OH)2 was modified via a template-free method by using different nickel salt. [•] The effects on the morphology and electrochemical behaviors were investigated. [•] The β-Ni(OH)2–SO4 2−/Ni-foam electrode displays 1025.3Fg−1 at 1.0Ag−1. [ABSTRACT FROM AUTHOR]

Highlights: [•] Al-substituted β-Ni(OH)2 were prepared by a simple template-free growth method. [•] The effect of Al contents on the electrochemical performances was investigated. [•] The specific discharge capacity was greatly enhanced by the addition of Al. [Copyright &y& Elsevier]

Abstract: A novel three-dimensional electrode consisting of Pd doped porous Ni film supported on Ni foam (Pd-porous Ni/Ni) is successfully prepared. The porous Ni film is synthesized by electrodeposition of Ni nanoparticles using hydrogen bubbles as a dynamic template. Pd doping is carried out via a chemical replacement reaction between Ni film and Na2PdCl4 solution. The obtained electrode exhibits a three-dimensional (3D) porous structure allowing the full utilization of catalyst surface active sites. The morphology of the electrode and the distribution of Pd on Ni particle surfaces are characterized by scanning electron microscope and energy dispersive X-ray spectrometer. The structure is analyzed using an X-ray diffractometer. The catalytic performance of the porous 3D electrode is evaluated by voltammetry and chronoamperometry. Results show that the electrode displays high catalytic activity and good stability for NaBH4 electrooxidation. The oxidation current density of NaBH4 on the Pd-porous Ni/Ni in 3.0 mol L−1 NaOH containing 0.1 mol L−1 NaBH4 at −0.6 V reaches 2.2 A mg−1, which is about 22 times of that on Pd/C (0.1 A mg−1) reported previously. [Copyright &y& Elsevier]

[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]

Abstract: The growth of CuO nanosheet arrays on Cu foil was demonstrated. The morphology and structure of the CuO were examined by scanning electron microscopy and X-ray diffraction spectroscopy. The catalytic performance of the obtained CuO/Cu electrode for hydrogen peroxide electroreduction in 3.0moldm−3 KOH was evaluated by means of cyclic voltammetry and chronoamperometry. The CuO/Cu electrode shows an onset potential for H2O2 electroreduction comparable to Co3O4 nanowire arrays grown on Ni foam and around 100mV more negative than precious metal catalysts, such as Pt and Pd, demonstrating its good catalytic activity for H2O2 electroreduction. The stabilized mass current density for H2O2 electroreduction on the CuO/Cu electrode at −0.3V reached about 57% of that on Co3O4 nanowire arrays grown on nickel foam. Compared to conventional fuel cell electrodes fabricated by mixing active materials with conducting agents and polymer binders, this electrode of CuO nanosheet arrays directly grown on Cu has superior mass transport property, which combining with its low-cost and facile preparation, make it a promising electrode for fuel cell using H2O2 as the oxidant. [Copyright &y& Elsevier]

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]

Abstract: We report a new method of preparation of a methanol-tolerant Se/Ru cathode catalyst for the direct methanol fuel cell (DMFC) , whereby selenium is deposited on ruthenium nanoparticles by H2-reduction of SeO2 in aqueous solution at room temperature. The obtained Se/Ru(aq) was studied by electrochemical measurements and tested as a cathode catalyst in H2–air and direct methanol fuel cells. The new catalyst formulation (Se/Ru(aq)) is shown to be superior to Se/Ru synthesized from xylenes solvent and to Ru black by RRDE measurements, in terms of both activity and selectivity for complete oxygen reduction to water. Although Ru black is less active, the Tafel slopes and activation energies of Se/Ru catalysts and reduced-Ru black are similar, implying similar ORR mechanisms. In H2–air fuel cell tests, Se/Ru(aq) was more active than Se/Ru(xyl) at all voltages. Compared to Ru black, Se/Ru(aq) was superior at low current densities, but Ru black slightly exceeded the performance of Se/Ru at high current densities. To explain the RRDE and fuel cell observations, the two roles of Se as an inhibitor of Ru oxidation and as a site-blocker are discussed. [Copyright &y& Elsevier]

Abstract: Spherical clusters of Ni(OH)2 nanosheets are directly grown on skeletons of nickel foam via a facile template-free spontaneous growth method. The obtained electrode (β-Ni(OH)2/Ni-foam) is characterized by X-ray diffractometry, scanning and transmission electron microscopy and thermal analysis. Results show that Ni(OH)2 has a β-phase structure and presents on the nickel foam skeleton mostly as spherical clusters with a diameter of ∼10μm. The spheres are composed of nanosheets with thickness of ∼60nm, width of ∼230nm and length up to ∼2μm, and the nanosheets are assembled by nanoparticles with diameter of ∼20nm. The electrochemical performance of the β-Ni(OH)2/Ni-foam electrode is evaluated by cyclic voltammetry and galvanostatic charge–discharge tests. The difference between the oxygen evolution reaction onset potential and the anodic peak potential for this electrode (∼100mV) is larger than that for β-Ni(OH)2 nanosheets and nanotubes powder electrode (∼65–77mV) and much larger than that for commercial spherical β-Ni(OH)2 powder electrode (∼25–47mV), indicating that the β-Ni(OH)2/Ni-foam electrode can be fully charged. The specific discharge capacity of β-Ni(OH)2 in the β-Ni(OH)2/Ni-foam electrode reaches 275mAhg−1, which is close to the theoretical value, lower than that of β-Ni(OH)2 nanotubes (315mAhg−1), but higher than that of nanosheets (219.5mAhg−1), commercial micrometer grade spherical powders (265mAhg−1) and microtubes (232.4mAhg−1). [Copyright &y& Elsevier]

Abstract: The open circuit potentials (OCPs) of H2O2 at Pt, Pd, Au, and glassy carbon electrodes are measured in H2SO4 and NaOH electrolyte solutions. Effects of concentration of H+, OH− and H2O2 as well as temperature on the OCP of H2O2 are investigated. The OCP of H2O2 is much lower than its theoretical reduction potential in both acidic and basic medium. The OCP is actually a mixed potential of H2O2 electroreduction and electrooxidation simultaneously occurring at electrode surfaces and it is more close to the equilibrium potential of H2O2 electrooxidation rather than electroreduction. The OCP of H2O2 is around 0.77–0.80V at [H+]=[H2O2]=1.0moldm−3 in H2SO4 solution and is about 0–0.06V at [OH−]=[H2O2]=1.0moldm−3 in NaOH at 298K on Pt, Pd, Au and GC electrodes. The OCP of H2O2 is independent of H2O2 concentration within the range of 0.01 to 1.0moldm−3. It increases approximately linearly with the logarithm of H+ concentration from 0.02 to 2.0moldm−3, decreases with the logarithm of OH− concentration from 0.01 to 1.0moldm−3 and decreases with increase of temperature from 278K to 333K. The linear equations were presented and discussed. [Copyright &y& Elsevier]

Abstract: Nanowire arrays of mixed oxides of Co and Ni freely standing on Ni foam are prepared by a template-free growth method. The effects of Ni content on the morphology, structure and catalyst performance for oxygen evolution reaction are investigated by scanning electron microscopy, X-ray diffraction spectroscopy and electrochemical techniques including cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. A transformation from nanowire arrays to nanoplate arrays is found with the increase of the atomic ratio of Ni to Co in the preparation solution. The NixCo3−xO4 electrode obtained at 1:1 of Ni:Co in the preparation solution exhibits nanowire array structure and has better catalytic performance for oxygen evolution reaction than other NixCo3−xO4 and Co3O4 electrodes. The catalytic activities of the NixCo3−xO4 and Co3O4 electrodes are correlated with their surface roughness. Superior stability of the NixCo3−xO4 nanowire array electrode is demonstrated by a chronopotentiometric test. The reaction orders with respect to OH− on the NixCo3−xO4 electrode are close to 2 and 1 at low and high overpotentials, respectively. [Copyright &y& Elsevier]

Abstract: Direct carbon fuel cells are promising power sources using solid carbon directly as fuel. Their performances significantly depend on the electrooxidation activity of carbon fuel. Electrooxidation of activated carbon particulates in molten Li2CO3–K2CO3 was investigated by potentiodynamic and potentiostatic method. Results indicated that the electrooxidation performance of activated carbon was significantly enhanced by pre-soaking with Li2CO3–K2CO3 and by treatment with HF, HNO3 and NaOH, respectively. The onset potential negatively shifted by around 100 mV and the current density increased by around 50 mA cm−2 after pre-soaking. The non-oxidant acids (HF) treatments are more effective than oxidant acid (HNO3) and base (NaOH) treatments. HF treated activated carbon exhibited the highest activity among all the samples. The enhancement in electrooxidation performance can be closely correlated with the increase in surface area and porosity caused by acid and base treatments. [Copyright &y& Elsevier]

Abstract: Au/Ni-foam electrodes with three dimensional network structures are prepared by simple spontaneous deposition of nano-sized Au particles onto nickel foam surface in an aqueous solution of AuCl3. Their morphology and catalytic performance for NaBH4 electrooxidation and H2O2 electroreduction in NaOH solution are investigated. Au particles with diameters smaller than 100nm are uniformly deposited on the whole surface of all skeletons of the nickel foam substrate. The onset potential for NaBH4 electrooxidation and H2O2 electroreduction is about −1.2V and −0.1V, respectively. A direct liquid feed alkaline NaBH4–H2O2 fuel cell is constructed using Au/Ni-foam electrode as both the anode and the cathode. The effects of the concentration of NaBH4 and H2O2 and operation temperature on the fuel cell performance are investigated. The fuel cell exhibits an open circuit voltage of about 1.07V and a peak power density of 75mWcm−2 at a current density of 150mAcm−2 and a cell voltage of 0.5V operating on 0.2moldm−3 NaBH4 and 0.5moldm−3 H2O2 at 40°C. [Copyright &y& Elsevier]

Abstract: A high performance alkaline direct borohydride–hydrogen peroxide fuel cell with Pt–Ru catalyzed nickel foam as anode and Pd–Ir catalyzed nickel foam as cathode is reported. The electrodes were prepared by electrodeposition of the catalyst components on nickel foam. Their morphology and composition were analyzed by SEM–EDX. The effects of concentrations of NaBH4 and H2O2 as well as operation temperature on the cell performance were investigated. The cell exhibited an open circuit voltage of about 1.0V and a peak power density of 198mWcm−2 at a current density of 397mAcm−2 and a cell voltage of 0.5V using 0.2moldm−3 NaBH4 as fuel and 0.4moldm−3 H2O2 as oxidant operating at room temperature. Electrooxidation of NaBH4 on Pt–Ru nanoparticles was studied using a rotating disk electrode and complete 8e− oxidation was observed in 2moldm−3 NaOH solution containing 0.01moldm−3 NaBH4. [Copyright &y& Elsevier]

Abstract: Pd nanoparticles were immobilized on Au disk electrode and kinetics of hydrogen peroxide electroreduction on the Pd electrode in 0.1M H2SO4 solution was investigated using a rotating disk electrode method. The phase and particle size of palladium were characterized by XRD measurements. The morphology of Pd on Au was examined using SEM. We found that the hydrogen peroxide reduction on Pd nanoparticles proceeds via a two-electron process. The reaction order is one with respect to hydrogen peroxide. An apparent activation energy of 55kJmol−1 was calculated from exchange currents at different temperature. The lower activation energy and higher exchange current density demonstrated that hydrogen peroxide reduction has a faster kinetics than oxygen reduction. Electrolyte anions significantly affect hydrogen peroxide reduction activity, and the activity decreases in the order > >Cl−, which is consistent with the increasing adsorption bond strength of the anions. [Copyright &y& Elsevier]

Abstract: Mg–Li–Al–Ce–Zn and Mg–Li–Al–Ce–Zn–Mn alloys were prepared using a vacuum induction melting method. Their electrochemical oxidation behavior in 0.7M NaCl solution was investigated by means of potentiodynamic polarization, potentiostatic oxidation, electrochemical impedance technique and scanning electron microscopy examination. Their utilization efficiencies and performances as anode of metal–hydrogen peroxide semi-fuel cell were determined. The Mg–Li–Al–Ce–Zn–Mn exhibited higher discharge activity and utilization efficiency than Mg–Li–Al–Ce–Zn, and gave improved fuel cell performance. The utilization efficiency of Mg–Li–Al–Ce–Zn–Mn is comparable with that of the state-of-the-art magnesium alloy anode AP65. The magnesium–hydrogen peroxide semi-fuel cell with Mg–Li–Al–Ce–Zn–Mn anode presented a maximum power density of 91mWcm−2 at room temperature. Scanning electron microscopy and electrochemical impedance studies indicated that the alloying element Mn prevented the formation of dense oxide film on the alloy surface and facilitated peeling off of the oxidation products. [Copyright &y& Elsevier]

Abstract: Spinel structure Co3O4 nanoparticles with an average diameter of around 17nm were prepared and evaluated as electrocatalysts for H2O2 reduction. Results revealed that Co3O4 exhibits considerable activity and good stability for electrocatalytic reduction of H2O2 in 3M NaOH solution. The reduction occurs mainly via the direct pathway when H2O2 concentration is lower than 0.5M. An Al-H2O2 semi fuel cell using Co3O4 as cathode catalyst was constructed and tested at room temperature. The fuel cell displayed an open circuit voltage of 1.45V and a peak power density of 190mWcm−2 at a current density of 255mAcm−2 operating with a catholyte containing 1.5M H2O2. This study demonstrated that Co3O4 nanoparticles are promising cathode catalysts, in place of precious metals, for fuel cells using H2O2 as oxidant. [Copyright &y& Elsevier]

Abstract: Mg–Li, Mg–Li–Al and Mg–Li–Al–Ce alloys were prepared and their electrochemical behavior in 0.7M NaCl solutions was investigated by means of potentiodynamic polarization, potentiostatic current–time and electrochemical impedance spectroscopy measurements as well as by scanning electron microscopy examination. The effect of gallium oxide as an electrolyte additive on the potentiostatic discharge performance of these magnesium alloys was studied. The discharge activities and utilization efficiencies of these alloys increase in the order: Mg–LiMg–Li–Al>Mg–Li–Al–Ce. Mg–Li–Al–Ce exhibited the best performance in term of activity, utilization efficiency and activation time. [Copyright &y& Elsevier]

Abstract: The direct carbon fuel cell is a special type of high temperature fuel cell that directly uses solid carbon as anode and fuel. As an electrical power generator for power plants, it has a higher achievable efficiency (80%) than the molten carbonate and solid oxide fuel cells, and has less emissions than conventional coal-burning power plants. More importantly, its solid carbon-rich fuels (e.g. coal, biomass, organic garbage) are readily available and abundant. In this review, some fundamental study results of electrochemical oxidation of carbon in molten salts are summarized. Recent developments in direct carbon fuel cell configurations and performance are also discussed. [Copyright &y& Elsevier]

A series of prototype direct methanol fuel cells (DMFCs) were constructed and operated under identical procedures and conditions except for the surface compositions of the anode electrocatalysts. The cathode electrocatalyst was Pt black (loading 2 mg/cm2, specific surface area: ca. 27 m2/g), the electrolyte membrane was Nafion™ 117, and the anode electrocatalysts were a series of Pt–Ru adatom (Pt–Ruad) nanoparticles (loading 2 mg/cm2, specific surface area: ca. 27 m2/g) prepared by a direct surface reductive deposition of Ruad onto Pt black. The optimum surface coverage of Pt by Ruad was ca. 33% for DMFCs operating at 60 °C. The optimum ranged from ca. 30 to 60% at 90 °C. A DMFC using Pt–Ruad nanoparticles supported on carbon (Vulcan XC-72™) as anode electrocatalyst was operated for 20 days at 8 h each day without loss of activity. These results, combined with those from an in situ cyclic voltammetry study, indicate that no significant Ruad dissolution and/or redistribution occurred during fabrication and operation of the prototype DMFCs. [Copyright &y& Elsevier]

The surface of Pt nanoparticles was cleaned and saturated with hydrogen by treatment first with a 3% aqueous solution of H2O2 and then with hydrogen gas under water at room temperature. Reaction between the surface hydrogen and aqueous RuCl3 deposited 0.18 surface equivalents of Ruad onto the Pt nanoparticles. The deposition was repeated several times, with each reaction depositing ∼0.18 surface equivalents more Ruad onto the Pt–Ruad nanoparticles. The resulting Pt–Ruad nanoparticles were analysed using cyclic voltammetry, CO stripping voltammetry, and as catalysts for electrooxidation of MeOH in three-electrode experiments and in prototype direct methanol fuel cells. The optimum surface coverage (θRu) for electrooxidation of MeOH was ∼0.33 under these conditions. [Copyright &y& Elsevier]

We report the performance of a polymer electrolyte membrane direct 2-propanol fuel cell (DPFC). The cell consisted of a Pt-Ru (atomic ratio of 1:1) black anode, a Pt black cathode, and a Nafion®-117 membrane electrolyte. The cell was operated at 90 °C with aqueous 2-propanol as fuel and with oxygen as oxidant. The performance of the cell operating on 2-propanol is substantially higher than when it was operating on methanol at current densities lower than ∼200 mA/cm2. The electrical efficiency of the direct 2-propanol fuel cell is nearly 1.5 times that of the direct methanol fuel cell at power densities below 128 mW/cm2. Studies on the effects of electrocatalyst loading, of 2-propanol concentration, and of oxygen pressure on cell performance indicate that the cells operating on 2-propanol require lower anode and cathode loadings than cells operating on methanol. Cathode poisoning by 2-propanol is less severe than by methanol. Hydrogen gas evolution observed at the anode at low current densities indicated that catalytic dehydrogenation of 2-propanol occurred over the anode catalyst. A rapid voltage drop occurred at high current densities and after operating the cell for extended periods of time at constant current. The rapid voltage drop is an anode phenomenon. [Copyright &y& Elsevier]

The organometallic precursor Ru4(μ-H)4(CO)12 (1) reacts with dihydrogen (60 atm, room temperature hexane as solvents, 3 h) over either blacked Pt gauze or Pt black powder to deposit Ru adatoms (Ruad) and CO on the Pt surface. The deposition is self-poisoned by adsorbed CO, stopping when a specific coverage of Pt by CO is reached. The results from the electrooxidation of the adsorbed CO, from base voltammograms recorded in aqueous sulfuric acid, from exhaustive anodic stripping of Ruad, and from the potentiodynamic and potentiostatic electrooxidation of MeOH, all show that the deposition self-poisons after ca. 0.05 surface equivalents (moles Ruad vs. moles Pt surface) of Ruad are deposited on blacked Pt gauze. The deposition over Pt black powder self-poisons after depositing ca. 0.10 surface equivalents of Ruad. A direct CH3OH fuel cell using the resulting black Pt–Ruad powder was constructed by hot-pressing the catalyst into a Nafion® membrane. Contrary to expectations, the Pt–Ruad catalyst did not lose significant amounts of surface Ru during either hot pressing the membrane electrode assembly, nor during operation of the fuel cell at 90 °C. [Copyright &y& Elsevier]

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]

Following the ammonia treatment, the pores created by the folds allow for electrolyte storage and facilitate ion transport. The interlayer spacing between MXene nanosheets widens due to the volume increase when water freezes. The generous ion transport paths and redox-active ammonium ions offer higher specific capacity and faster reaction kinetics. [Display omitted] Ti 3 C 2 T x MXene demonstrates excellent potential as an anode material for sodium-ion capacitors. However, the narrow interlayer spacing and self-stacking phenomenon limit its applicability. In this study, we demonstrate an easy two-step method involving freezing and crumpling of MXene nanosheets to improve their Na-ion storage via the addition of ammonium ions (referred to as FCM nanosheets). Flat MXene particles aggregate and undergo folding in an alkaline solution. Ammonium ions can penetrate the gaps between MXene nanosheets, expanding interlayer spaces and inducing the formation of folds. Compared to MXene nanosheets, FCM nanosheets exhibit improved ion transfer kinetics and additional high capacity owing to the intercalated ammonium ions. The manufactured FCM anode exhibits remarkable electrochemical properties, including a high specific capacity of 313 mAh g−1 and stability over 15,000 cycles. [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]