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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]

Abstract: The electrochemical performances of magnesium, magnesium–lithium–aluminum–cerium and magnesium–lithium–aluminum–cerium–yttrium as the anode of magnesium–hydrogen peroxide semi-fuel cells have been studied by methods of potentiodynamic, potentiostatic and electrochemical impedence measurements. The surface morphologies of magnesium and its alloys have been examined by scanning electron microscopy (SEM). It has been found that magnesium–lithium–aluminum–cerium and magnesium–lithium–aluminum–cerium–yttrium electrodes are less corrosion resistant than that of magnesium electrode in 0.7molL−1 NaCl solution and the corrosion current density decreases with the following order: magnesium

The highly porous electrode of a crisscrossed CoNi nanosheets array grown on reduced graphene oxide decorated Ni foam (CoNi/rGO@Ni foam) is fabricated through a facile dip and dry method followed by electroreduction and electrodeposition methods. The phase composition and morphology of the electrode are characterized by XRD, SEM, TEM, and EDS. In single electrode tests, CoNi/rGO@Ni foam electrode displays an excellent catalytic performance (330 mA cm−2 at 0.6 V) and stability towards urea electrooxidation when comparing to Ni foam and CoNi nanosheets modified Ni foam (CoNi@Ni foam) electrode. Besides, a low initial oxidation potential of urea electro-oxidation to 0.14 V is achieved on the CoNi/rGO@Ni foam electrode. The introducing of rGO to the electrode greatly reduced the reaction activation energy from 14.47 to 10.35 kJ mol−1. Besides, large active surface area (261.67 cm2) is also obtained from the electrode. The CoNi/rGO@Ni foam anode exhibits a maximum power density of 12.58 mW cm−2 in direct urea-hydrogen peroxide fuel cell tests. Excellent performance shows in single electrode tests and fuel cell tests suggest that addition of rGO to the electrode is an easy and feasible method to enhance the performance of the catalyst. • Highly porous electrode: crisscrossed nanosheets array grows on rGO modified Ni foam. • The influence of rGO on the catalytic performance of the electrode was researched. • Low initial oxidation potential towards urea electro-oxidation was obtained. • Achieved an excellent performance and stability when practical use in DUHPFC. [ABSTRACT FROM AUTHOR]

An original three-dimensional self-supported reduced graphene oxide (rGO) foam is successfully prepared in this work. This novel support material, modified with Co nanosheets and Au nanoparticles, is employed as a high-performance catalyst for NaBH 4 electrooxidation under alkaline condition. The surface chemical component and morphology of the catalyst is characterized by X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope. The synthesized electrode exhibits excellent performance (1.35 A cm−2 at 0 V) towards NaBH 4 electrooxidation. The unique structure of rGO foam caused a large electrochemical active surface area (EASA (Au) = 390 m2 g−1), low electrochemical impedance, as well as 55.4% utilization efficiency of NaBH 4. Also, catalytic kinetic parameters during the electrooxidation reaction of NaBH 4 in a low NaBH 4 concentration are investigated. Results indicate that oxidation of BH 4 − is a first-order reaction, and the exchanged number of electrons obtained at the CoAu/rGO foam electrode is 6.9. Finally, we practically apply it to a direct borohydride-hydrogen peroxide fuel cell (DBHPFC). This work suggests that the prepared rGO foam is an excellent current collector, and CoAu/rGO foam electrode is a promising anode catalyst to apply in DBHPFC. Image 1 [ABSTRACT FROM AUTHOR]

Catalytic performance and NaBH 4 utilization are two crucial concerns in the electrooxidation of NaBH 4. To improve the inherent properties of regular performance and low fuel utilization of the transition metal Co and Ni, an efficient anode catalyst of ultra-thin CoNi nanosheets modified novel 3D self-supported reduced graphene oxide foam is prepared in this work. The alkaline condition borohydride oxidation reaction on the prepared catalyst is investigated in a typical three-electrode system. The prepared catalyst shows a high performance due to the large electrochemical active surface area, low activation energy (8.29 kJ·mol−1), and the small electrochemical impedance it embraced. Linear scan voltammetry recorded in a low concentration of NaBH 4 suggests that borohydride oxidation is a first-order reaction on the prepared catalyst. Based on the unique structure of the catalyst, which is useful to capture the hydrogen and perform further oxidation of hydrogen, higher utilization of NaBH 4 achieved on the catalyst. Besides, the prepared anode catalyst applied to a direct borohydride-hydrogen peroxide fuel cell (DBHPFC). The results of polarization curve and power density curves, as well as stability research, all indicate that the as-prepared catalyst is a highly efficient anode material for application in DBHPFC. Unlabelled Image • Novel 3D self-supported rGO foam skeleton was prepared by a simple template method. • The catalytic activity of CoNi-NS/rGO foam is higher than CoNi-NS/Ni foam electrode. • Self-supported rGO foam matrix improved the utilization efficiency of NaBH4. • CoNi-NS/rGO foam anode catalyst exhibited highest power density of 140 mW·cm−2. [ABSTRACT FROM AUTHOR]

Aqueous magnesium ion battery as a new energy storage system is always explored due to excellent properties with high theoretical specific capacity, low-cost and safe aqueous electrolytes. However, the study on available material as anode in aqueous magnesium ion battery is very limited, which is the main reason that the kinetics of multivalent magnesium ions deinserted from the host material is very difficult. In this work, the nanoneedle FeVO 4 ·0.9H 2 O as available anode material is prepared and further modified by compositing with graphene. The FeVO 4 ·0.9H 2 O/Graphene composite exhibits the more excellent electrochemical performance, for example, the initial discharge capacity of FeVO 4 ·0.9H 2 O/Graphene electrode at the current density of 50 mAh g −1 in 1.0 mol L −1 MgSO 4 electrolyte is 183.8 mAh g −1 , but that of the FeVO 4 ·0.9H 2 O is 150.3 mAh g −1 . Therefore, the aqueous magnesium ion full battery is successfully assembled by FeVO 4 ·0.9H 2 O/Graphene as anode, 1.0 mol L −1 MgSO 4 as electrolyte and Mg-OMS-1 as cathode, which can obtain the discharge capacity of 53.1 mAh g −1 at a current density by calculate the total mass of two electrodes and the a high energy density of 58.5 Wh kg −1 . [ABSTRACT FROM AUTHOR]

[Display omitted] • A modified guar gum layer inhibits the Zn dendrites growth. • Breaking intramolecular hydrogen bonds prevents the HER. • RFH-GG@Zn symmetric cell demonstrates 2500 h cycling life. • AC||RFH-GG@Zn capacitors present cycling stability of 60,000 cycles. Zn-based energy storage devices such as Zn ion hybrid capacitor (ZICs) and Zn ion batteries (ZIBs) have attracted extensive attention due to the advantages of low cost, chemical stability, and high capacity of Zn metal anode. However, the Zn anode faces the difficulties of inevitable dendrite growth and hydrogen evolution reaction (HER) during cycling. Herein, we construct guar gum film, as artificial solid electrolyte interphase, on the Zn metal to suppress the dendrite grown and promote Zn deposition. Meanwhile, the Zn2+ desolvation process is enhanced by regulating the hydrogen bonding inside the film. As a result, the Zn anode coated with guar gum with rich free hydroxyl groups (RFH-GG@Zn) remains a low overpotential (45 mV) after an alternant plating/stripping process for more than 2,500 h. The application of RFH-GG@Zn promotes the cycling performance and rate ability of ZICs and ZIBs. This work aims to prepare high-performance Zn metal anodes by reducing intramolecular hydrogen bonding to enhance the protective effect of the coating on Zn anodes. [ABSTRACT FROM AUTHOR]

Scheme 1. Material synthesis. [Display omitted] • Characterization results confirmed the crystalline structure of the prepared samples. • FJH is more efficient in terms of time and energy than traditional heating. • HTC and FHC exhibited excellent performance as anode materials for LIBs and PIBs. • Graphitized coal can be a good alternative to graphite as anodes for LIBs and PIBs. Natural graphite, commonly used in energy storage applications such as the battery industry, is marked as a supply-risk material due to the elevated demand and limited resources. The synthetic graphite process is inefficient, so there is a highly required for alternative methods of making graphite as anode material. In this study, we report two efficient methods for catalytic graphitization of coal using high-temperature heating and flash Joule heating (FJH). Using both methods, the structure and morphology characterizations have demonstrated the successful structural conversion of coal from an amorphous structure into a crystalline structure. When the obtained graphitized coal samples via the high-temperature heating method (HTC) and via the FJH method (FHC) were used as anodes for lithium-ion batteries (LIBs) and potassium-ion batteries (PIBs), the HTC and FHC presented outstanding rate capability and remarkable stable cycling performance. The HTC and FHC anodes delivered initial charge capacities of 322.5 and 321.3 mAh·g−1, respectively, at a current density of 0.1C. for LIBs. When used as anodes in PIBs, the HTC and FHC delivered initial charge capacities of 265.4 and 262.2 mAh·g−1 at 0.1C current density. These results make the HTC and FHC promising materials for developing energy storage applications. Therefore, this work exploited the low price of coal and its abundant reserves, combined with the FJH technique, which is an effective method for saving energy and time, to produce high-quality graphitized coal materials, which can make this process green and economically attractive. [ABSTRACT FROM AUTHOR]

Organic polymer materials attract lots of attention as promising anode materials for lithium ion batteries (LIBs) due to the superior lithium ion storage capability and low cost. However, the inherent insulativity of the polymer anodes results in the unsatisfactory electrochemical performance. Herein, we design and construct a hierarchical flowers-like polyaniline-coated (PANI) pyromellitic dianhydride-based polyimide (PPI) composite (PANI-PPI-9). Benefiting from the core-shell structure, the PPI presents an improved electrochemical performance, especially the remarkable cycling life (503 mAh g−1 at 1.5 A g−1 after 2400 cycles). Ex-situ characterizations and kinetics analyses also verify that the PANI shell serves as the electronic transport highway without obstructing the Li storage of PPI. This work highlights the potential application of the multifarious polymer-based composite electrodes for the lithium ion batteries. • The structure construct strategy to design and prepare the PANI-coated PPI micron flowers. • Aromatic rings in the polyimide provide a large number of lithium storage sites. • The PANI-PPI-9 exhibits improved long-cycling and rate performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • SnS x /N-rGO-30 with rich heterostructures was prepared by a hydrothermal route. • Built-in electric field greatly accelerates the charge transfer and ion diffusion. • SnS x /N-rGO-30 shows high Li+ storage capacity of 1273 mAh g−1 at 0.1 A g−1. • SnS x /N-rGO-30 shows high Na+ storage capacity of 640 mAh g−1 at 0.1 A g−1. Metal sulfides have been broadly used as potential candidates in lithium-ion and sodium-ion batteries. However, they usually undergo huge volume expansion and shrinkage, inferior electronic conductivity and sluggish redox reaction kinetics. Construction of heterostructure turns out to be a successful route to accelerate the charge transfer kinetics. Herein, ultrafine SnS x nanoparticles (∼5 nm) with abundant heterostructure are anchored on N-doped graphene through a hydrothermal approach. The rich heterostructures and the interfacial effect induced by built-in electric field significantly accelerate the charge transport and ion diffusion. The SnS x /N-rGO-30 nanocomposite displays large discharge capacity of 1273 mAh g−1 at 0.1 A g−1, superior rate ability (594 mAh g−1 even at 10 A g−1) as well as excellent cycling performance as anodes for Li-ion batteries. As for sodium-ion storage, the SnS x /N-rGO-30 nanocomposite exhibits high reversible capacity of 640 mAh g−1 at 0.1 A g−1 and high rate capability of 225 mAh g−1 at 10 A g−1. [ABSTRACT FROM AUTHOR]

• Cable-like PI@CNTs is designed and prepared via an in-situ polymerization approach. • The PI@CNTs anode exhibits far better long-term cycling performance than pure PI. • The structure of PI@CNTs facilitates Li ion diffusion and electron transportation. Polyimide (PI) with C = O groups and C 6 rings is considered as a promising anode material for lithium ion batteries. However, the potential application of PI is extremely hindered by its inherent properties with unsatisfied lithium ions diffusion and electron conductivity. Herein, the PI nanoflakes are grown on the carbon nanotubes (CNTs) to construct a cable-like structure (PI@CNTs) via an in-situ polymerization approach. The dispersed PI nanoflakes provide shorter lithium ion transmission distance and the CNTs substrate promotes electron transportation, leading to enhanced electrochemical performance. When served as anode material, PI@CNTs exhibits a specific capacity of 493 mAh g−1 at 1 A g−1 after 2000 cycles, demonstrating remarkable long-term cycling properties. Moreover, the kinetic analysis reveals that the increased capacity can be ascribed to an enlarged diffusion-controlled process. In addition, the COMSOL simulation displays the high concentration of Li ions flux on the PI@CNTs surface. This work suggests a facile strategy to fabricate capable hierarchical polymer electrode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Nickel-cobalt nanowire arrays (Ni-Co NWAs) electrode is prepared by one-step galvanostatic electrodeposition with a polycarbonate membrane as the template. By adjusting the Co proportion in the Ni and Co bath solution into 10%, the optimal Ni-Co NWAs electrode in terms of relatively lower onset potential and highest current density towards urea electro-oxidation is obtained. Its catalytic performance is investigated by constructing single direct urea/hydrogen peroxide (H 2 O 2 ) fuel cell. Results show that a peak power density of 7.4 mW cm −2 and an open circuit voltage of 0.92 V are achieved at room temperature when 9.0 mol L −1 KOH and 0.33 mol L −1 urea are used as the anolyte, H 2 SO 4 and H 2 O 2 as the catholyte. Additionally, the urea/H 2 O 2 fuel cell also demonstrates excellent stability during short term duration test. [ABSTRACT FROM AUTHOR]

In this work, Co(OH) 2 buds direct growth on Ni foam (Co(OH) 2 buds/Ni foam) is prepared via a hydrothermal method. Their structure and morphologies are characterized by using X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. Result shows that the Co(OH) 2 buds are assembled by several nanorods and uniformly covered on the surface of Ni foam. Due to its unique structure, the Co(OH) 2 buds/Ni foam electrode shows high capacitive performance and long cycle life. The specific capacitance of Co(OH) 2 buds/Ni foam is as high as 2041 F g −1 at a current density of 3 mA cm −2 in 6 M KOH electrolyte, and 811 F g −1 even at a high current density of 60 mA cm −2 . The capacitance of the Co(OH) 2 buds/Ni foam electrode remained 72.4% after 1000 cycles at 18 mA cm −2 . An asymmetric supercapacitor was successfully assembled, in which Co(OH) 2 buds/Ni foam and AC used as positive and negative electrode, respectively. The energy density of the AC//Co(OH) 2 buds/Ni foam supercapacitor reaches to 20.3 W h kg −1 at a power density of 90.6 W kg −1 . Our result shows that the Co(OH) 2 materials are promising candidate for electrochemical energy applications. [ABSTRACT FROM AUTHOR]

Carbon fiber cloth (CFC) supported Ni and Co electrodes are prepared by electrodeposition (Ni/CFC and Co/CFC). Their catalytic performance for H2O2 electrooxidation in KOH solution is investigated and compared with Au/CFC electrode. Ni/CFC electrode exhibits higher catalytic activity than Au/CFC and Co/CFC electrodes. The performance of a direct peroxide–peroxide fuel cell (DPPFC) with Ni/CFC anode and Pd/CFC cathode is examined. The cell shows a peak power density of 21.6 mW cm−2 at 20 °C and 53.8 mW cm−2 at 50 °C. The cell performance is improved with the increase of anolyte and catholyte flow rate and operation temperature. Results indicates that the performance of DPPFC with low-cost Ni/CFC anodes is comparable with those using precious metal anodes, e.g., Au/CFC and Pd/CFC. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical oxidation behaviors of Mg–8Li–3Al–0.5Zn and Mg–8Li–3Al–1.0Zn electrodes in 0.7 mol L−1 NaCl solution are investigated by methods of potentiodynamic polarization, potentiostatic oxidation, electrochemical impedance spectroscopy and scanning electron microscopy. The phase composition of Mg–8Li–3Al–0.5Zn and Mg–8Li–3Al–1.0Zn alloys is analyzed conducted by X-ray diffraction. The performances of Mg–8Li–3Al–0.5Zn and Mg–8Li–3Al–1.0Zn as the anode of Mg–H2O2 semi fuel cells are determined. The effect of Zn content on the corrosion resistant of these Mg–Li-based alloys is studied. It is found that the Mg–8Li–3Al–0.5Zn electrode has higher discharge activity and less corrosion resistance than that of Mg–8Li–3Al–1.0Zn electrode in 0.7 mol L−1 NaCl solution. The Mg–H2O2 semi fuel cell with Mg–8Li–3Al–0.5Zn anode presents a maximum power density of 100 mW cm−2 at room temperature, which is higher than that of Mg–8Li–3Al–1.0Zn anode (80 mW cm−2). The performance of semi fuel cell with the Mg–8Li–3Al–0.5Zn electrode is better than that with Mg–8Li–3Al–1.0Zn electrode, especially at higher current density (>30 mA cm−2). [Copyright &y& Elsevier]

Abstract: Sr-doped Li4Ti5O12 composites are prepared by a solid-state reaction method and characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy. Their electrochemical properties as the anode material of lithium ion batteries are investigated by galvanostatic charge and discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that Sr2+ doping increases the lattice parameter, reduces the particle size, decreases the charge transfer resistance, and significantly enhances the rate capability of Li4Ti5O12. The Sr-doped Li4Ti5O12 exhibits a specific discharge capacity of about 1.62 times that of pristine Li4Ti5O12 at 5C charge/discharge rate. Sr doping introduces a small amount of SrLi2Ti6O14 to the composites, which also makes a contribution to the specific capacity of Li4Ti5O12 at low charge/discharge potentials. [Copyright &y& Elsevier]

Abstract: A single chamber microbial fuel cell (MFC) with an air-cathode is successfully demonstrated using glucose–ceftriaxone sodium mixtures or ceftriaxone sodium as fuel. Results show that the ceftriaxone sodium can be biodegraded and produce electricity simultaneously. Interestingly, these ceftriaxone sodium–glucose mixtures play an active role in production of electricity. The maximum power density is increased in comparison to 1000mgL−1 glucose (19Wm−3) by 495% for 50mgL−1 ceftriaxone sodium+1000mgL−1 glucose (113Wm−3), while the maximum power density is 11Wm−3 using 50mgL−1 ceftriaxone sodium as the sole fuel. Moreover, ceftriaxone sodium biodegradation rate reaches 91% within 24h using the MFC in comparison with 51% using the traditional anaerobic reactor. These results indicate that some toxic and bio-refractory organics such as antibiotic wastewater might be suitable resources for electricity generation using the MFC technology. [Copyright &y& Elsevier]

Abstract: An investigation aimed at exploring a new approach to improve microbial fuel cell (MFC) performance and electron transfer rate through the addition of rhamnolipid was carried out. Results demonstrated that, for an air-cathode MFC operating on 1g L−1 glucose with different additions of rhamnolipid from 0 to 80mg L−1, the open circuit voltage (OCV) was 1.8-fold increased from 483 to 878mV, the maximum power density was 12.5-fold increased from 22 to 275W m−3 (0.6 to 7.6W m−2), while the corresponding current density of the maximum power density was 11.4-fold increased from 1.8 to 20.6A m−2, respectively. Anode discharge analysis suggested that the improvement of electron transfer from bacteria to anode can be attributed to the addition of rhamnolipid. The high power density achieved here may be due to the increase of permeability of cell membranes by the addition of rhamnolipid, which reduced the electron transfer resistance through the cell membrane and promoted the electron transfer rate and number, consequently enhancing the current and power output. A promising way of utilizing bio-surfactant to improve the energy generation of MFC was demonstrated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen-rich biomass carbon (N-CHC) was prepared by urea etching method. • N-CHC exhibits excellent capacity and rate performance as a K+ half-cell anode. • Large specific surface area, lots of defects and heteroatoms are key advantages. • The hybrid capacitor composed of N-CHC and AC exhibits high energy and power density. Potassium ion hybrid capacitors have the advantages of high energy density, high power density, and low cost, and are expected to replace expensive lithium ion storage devices in large-scale applications. Here, an innovative nitrogen-rich biomass carbon (N-CHC) is prepared using urea as the etchant and hemp core as the raw material, which has a high specific surface area of 1185.3 m2 g−1 and nitrogen content of 8.56%. In addition, it shows a capacity of 442.4 mAh g−1 as a potassium ion half-cell anode at 30 mA g−1. Even under the high current test of 2000 mA g−1, N-CHC also shows excellent performance (175.0 mAh g−1). Further, the good rate performance is attributed to the large-scale capacitance control by analyzing reaction process kinetics. And the constant current intermittent titration technique (GITT) results show that N-CHC has a larger K+ diffusion coefficient than unetched biomass carbon. The maximum energy density of the full carbon-based hybrid capacitor composed of N-CHC anode and activated carbon cathode is 127.36 Wh kg−1, and the maximum power density is 2371 W kg−1. [ABSTRACT FROM AUTHOR]

• The PTC-S as anode has an outstanding performance in 0.5 M LiCl + 0.5 M MgCl 2 aqueous solution. • The PTC-S exhibits a good rate ability and cycling stability. • PTC-S‖LiMn 2 O 4 has a high capacity and excellent cycling stability. Aqueous batteries are appealing for large-scale storage applications, due to their high safety level, low cost, and excellent durability. In this study, we reported a new anode material, namely sulfur perylene-3,4,9,10-tetracarboxylate (PTC-S), which is more stable than other electrode materials used in aqueous Mg-Li ion batteries. When PTC-S is used as the anode in 0.5 M MgCl 2 + 0.5 M LiCl with a current density of 50 mA g−1, the discharge specific capacity is 287.3 mAh g−1 at the initial cycle and the capacity retention rate is still close to 100% at over 1000 cycles. The monomer structural material conjugated with bifunctional groups can provide the space for the intercalation of Mg2+ and Li+ at the same time, shorten the ion transmission path and accelerate the transmission speed of metal ions in the electrode. In order to develop aqueous battery as quickly as possible, LiMn 2 O 4 and PTC-S are used as cathode and anode materials, respectively, in a dual-ion salt aqueous battery. The PTC-S‖LiMn 2 O 4 battery exhibits a high capacity and an excellent cycling stability performance in aqueous Mg-Li ion battery. The battery has a high capacity performance of 240.0 mAh g−1 at a voltage ranging from 0.0 V to 1.8 V, as well as a high specific energy density of 172.8 Wh kg−1 and remarkable cycling stability. PTC-S in 0.5 M MgCl 2 electrolyte has a current density of 100 mA g−1, a specific discharge capacity of 203 mAh g−1 and a first-cycle Coulomb efficiency close to 100%. Under the same test conditions, the discharge specific capacity is higher than that of the perylene-3,4,9,10-tetracarboxylic dihydride (PTCI) electrode (101 mAh g−1), and the capacity retention rate is increased by 30.4%. [ABSTRACT FROM AUTHOR]

• NiNb 2 O 6 @NC-2 hollow nanoparticles is used as rate capability anode for LICs. • The NiNb 2 O 6 @NC-2 exhibits a high specific capacity of 435.8 mAh g−1 at 50 mA g−1. • NiNb 2 O 6 decomposes into Ni metal and Li x Nb 2 O 6 in the 1st charge/discharge process. • The NiNb 2 O 6 @NC//AC LICs has a maximum energy density of 123.9 Wh kg−1. Searching for anode materials with fast Li+ intercalation kinetics to mitigate the dynamic imbalance with the rapid capacitive cathode is the fundamental strategy to achieve high energy-power density of Li-ion capacitors (LICs). Hence, NiNb 2 O 6 hollow nanoparticles are first synthesized by hydrothermal method and then sealed with a protective N-doped carbon shell to achieve the target NiNb 2 O 6 @NC composite. As the anode of LICs, the NiNb 2 O 6 @NC sample exhibits a high capacity of 435.8 mAh g−1 at 50 mA g−1 and excellent rate performance of 47.8% capacity retention with the current density increased to 2 A g−1. The lithium storage mechanism of NiNb 2 O 6 is proposed as a combined conversion reaction and an intercalation reaction, which the NiNb 2 O 6 decomposes into Ni metal and Li x Nb 2 O 5 during the 1st discharge/charge process. The irreversible Ni would not contribute to the reversible capacity and will improve the electric conductivity for fast transport of electrons and the Li x Nb 2 O 5 will act as the host for lithium ions by means of the intercalation mechanism. Furthermore, the assembled NiNb 2 O 6 @NC//activated carbon LICs exhibit a maximum energy density of 123.9 Wh kg−1 and the capacity retention reaches 86.1% after 5000 cycles. The superior electrochemical performances indicate that the rationally-designed NiNb 2 O 6 @NC is expected to be a potential anode material for LICs. [ABSTRACT FROM AUTHOR]

K-ion batteries (KIBs) are widely considered as a promising alternative to Li-ion batteries (LIBs) due to the cost effective and earth abundant features of K. However, identifying a potential anode for KIBs showing good capacity and stability is still challenging. Because traditional graphite suffers from poor stability owing to the large volume expansion during the insertion/extraction of K ions. Non-graphite carbon is a good candidate because of the disordered nature. A facile high temperature pyrolysis method was adopted to obtain bio-derived carbon materials. Among different kinds of biomass precursors, the porous dandelion seed with nitrogen doping shows the best electrochemical performance with a specific capacity of 168 mAh g−1. The nitrogen-doped carbon presents good K ion adsorption capability and enhanced wettability, which is demonstrated in Fig.S1. Moreover, after introducing activation agent (KOH) in the carbonization process, the capacity in improved to 243 mAh g−1. Meanwhile, the as-prepared carbon material delivers good capacity retention of 91% after 100 cycles. Therefore, the hierarchically porous doped carbon derived from renewable biomass precursor shows great economical potential as KIBs anode. Unlabelled Image • The bio-derived carbon activated by KOH maintain maintain an integrated porous microstructure. • The heteroatoms-doped bio-derived carbon exhibits high specific capacity as K ions anode. • The abundant bio-mass precursor enables large scale preparation of the carbon materials. [ABSTRACT FROM AUTHOR]

High-quality F-doped graphene as rate capability anode for Li-ion battery is prepared by a one-step arc-discharge method. The in-situ formation of LiF nano-particles in the first lithium insertion process enhance the interlayer spacing of graphene, thus provid enough void for rapid ion diffusion, which is capable to deliver much high reversible capacity, outstanding rate performance, and excellent cycling stability. • A high-quality F-modified graphene as rate capability anode for Li-ion battery is reported. • The structural evolution of F-modified graphene electrode during the Li+ insertion/extraction is investigated. • The F-modified graphene delivers a high reversible capacity, outstanding rate performance, and excellent cycling stability. The application of lithium ion battery (LIB) in portable electronics and electric vehicle has received tremendous attention, however, challenges remain in seeking suitable high-capacity anode materials with excellent rate performance and thus potentially to boost the energy/power density. Here we report an arc-discharge production of high-quality F-modified graphene as anode for LIB with high-rate capability. As a result of F-modified, the acquired graphene exhibits high atomic ratio of C/O, excellent electric conductivity and more crumpled and wrinkled surface. Interestingly, the in-situ formation of LiF nanoparticles during the first Li+ insertion process not only act as barriers to effectively prevent the agglomeration and re-stacking of graphene sheets but also enhance the interlayer spacing, thus providing enough void for rapid Li+ ion insertion/extraction. These optimized features enable the resultant F-modified graphene delivers a high reversible capacity (783.2 mAh g−1 at 100 mA g−1), outstanding rate performance (298.5 mAh g−1 at 10 A g−1), and excellent cycling stability (>91% capacity retention after 1000 cycles), providing great application prospect in high-enegy-power LIB. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous aluminum ion batteries (RAAB) have gained increasing attentions for large scale energy storage system due to their high safety, nontoxicity and low cost. However, lack of capable anode materials extremely hinders their potential application. As we all know, the anodic material of aluminum ion battery was limited, we report poly (3,4,9,10-perylentetracarboxylic diimide) (PPTCDI) under the different synthesis conditions as organic anode material for aqueous RAAB. The aluminum ions intercalation/deintercalation storage mechanism is affected by the different electrolyte concentrations. Upon their high capacity and cycling stability, our work would highlight potential application of conjugated polymer organic electrode materials for aqueous aluminum ion batteries. Unlabelled Image • The PPTCDI as anode in aqueous Al-ion battery was reported for the first time. • The Al-ion battery delivers excellent electrochemical cycling stability. • The aluminum ions intercalation/deintercalation storage mechanism is affected by the different concentrations of electrolyte. [ABSTRACT FROM AUTHOR]