Cycling Durability Research Articles

Multicomponent hierarchical Cu-based advanced cathode for ultrahigh capacity rechargeable Cu-Zn battery

Rechargeable aqueous Zn-based batteries (RAZBs) have emerged as a practically attractive option for large-scale energy storage applications due to their cost-effectiveness, safety, eco-friendliness, and high theoretical capacity. Nonetheless, the application of RAZBs at the grid scale is restricted by the drawbacks of cathode that exhibit low capacities and poor durability. In this work, a multicomponent hierarchical Cu@CuO@Cu2O cathode with superior electrochemical energy storage performance has been successfully synthesized by a fairly simple calcination method. Benefiting from its large active area, fast ion diffusion channel, high conductivity, and synergetic effect between different components, the resulting Cu@CuO@Cu2O electrode exhibits ultrahigh specific capacity (40.2 mAh cm−2, 402 mAh cm−3 at 10 mA cm−2), excellent rate capability (24.8 mAh cm−2, 248 mAh cm−3 at 100 mA cm−2) and satisfactory cycling durability (71.5 % capacity retention after 3800 cycles). To our knowledge, such high areal/volumetric specific capacity ranks top among previously reported Cu-based electrode and other aqueous electrodes. Furthermore, the fabricated Cu@CuO@Cu2O//Zn battery achieves an extraordinary energy density of 24.5 mWh cm−2 and a remarkable cyclic capability of 91 % capacity retention after 3000 cycles, highlighting its potential for large-scale energy storage in RAZBs.

Chemically Stable NiMoO4/NRGO Asymmetric Capacitor

AbstractIn this work, a chemically stable NiMoO4/NRGO nanocomposite was prepared via a facile hydrothermal method. The flower‐like structure of NiMoO4 (NMO) nanoparticles is randomly distributed on the surface of nitrogen‐doped reduced graphene oxide (NRGO) sheets, as observed in FESEM images. Compared to related reports, the NMO/NRGO (II) nanocomposite exhibits an excellent high surface area of 368.9 m2 g−1 and a mesoporous nature, as shown in N₂ adsorption‐desorption isotherms. The specific capacitance of the NMO/NRGO (II) electrode is 721 F g−1 at 1 A g−1 using a 6 M KOH electrolyte, retaining 91.2 % of its initial value after 5000 cycles. Electrochemical impedance spectroscopy (EIS) reveals that the electrode has a lower charge‐transfer resistance, indicative of good electrochemical behavior. An asymmetric device consisting of NMO/NRGO (II) || activated carbon (AC) electrodes exhibits a high energy density of 49.1 Wh kg−1 at 524.4 W kg−1 within a voltage range of 1.4 V, retaining 89 % of its initial capacitance after 5000 cycles, demonstrating good cyclic durability. These results suggest that the NMO/NRGO (II) electrode is a promising active material for supercapacitor devices.

Crystalline/Amorphous Co2P2O7 cathode with outstanding areal capacity for High-Performance Zinc-Cobalt battery

It is still a challenge to develop aqueous rechargeable Zn-based alkaline batteries with high energy density, power density and excellent stability. Herein, a crystalline/amorphous Co2P2O7 self-supporting on the Ni foam is fabricated as a cathode material of aqueous Zn-based alkaline batteries. The unique crystalline/amorphous structure endows the electrode material with more exposed active sites, higher redox species coverage, larger electrochemical surface area (ECSA), smaller charge-transfer resistance, lower reaction energy barriers and faster electrochemical reaction kinetics process, which clarifies an explicit structure–property relationship simultaneously. As a result, the crystalline/amorphous Co2P2O7 (CP-P-450) electrode assembled as CP-P-450//Zn battery achieves an extraordinary areal capacity of 2.49 mAh cm−2 at 5 mA cm−2, satisfactory rate performance, excellent cyclic durability (96.6 % retention after 4000 cycles) and impressive energy density (4.16 mAh cm−2) and peak power density (115.94 mW cm−2). The quasi-solid CP-P-450//Zn battery can drive a variety of electrical appliances working well even under abuse tests, demonstrating excellent safety and application potential. This study provides an effective strategy towards excellent comprehensive energy storage performance of aqueous Zn-based alkaline batteries through structuring the crystalline/amorphous phase in cathodes.

Controllable Synthesis and Growth Mechanism of Cracked Cowpea-Like NCNT Encapsulated with Fe3N Nanoparticles for High-Performance Anode Material in Lithium-Ion Batteries

Fe3N nanocrystals embedded in cracked N-doped carbon nanotubes (Fe3N@NCNT) with a cowpea-like shape are innovatively prepared by metal-catalyzed graphitization and nitridization processes based on melamine and FeC2O4 precursor. The new in-situ synthesis strategy is proved to be effective to open the NCNT using a migratory metal carbide nanocatalyst via expansion effect and fabricate a metal nitride embedded NCNT with fully active ingredients. The detailed tip-growth mechanism of cracked NCNT with latitudinal-longitudinal graphene layers is studied by in-situ XRD analysis of the phase evolution of melamine and FeC2O4, and ex-situ SEM/TEM investigation of the topography correlation of NCNT and Fe3C floating catalyst. The Fe3N@NCNT microclews based anodes have a moderate carbon content of 35.45 wt%, electroactive NCNT conductive network, abundant microcracks and an open short-cavity system, showing a stable discharge capacity of 667 mAh g−1 at 0.1C, outstanding rate capability of 448 mAh g−1 at 5C and remarkable long-term cycling stability of 546 mAh g−1 after 600 cycles at 1C. The combined good electronic/ionic conductivity of cracked NCNT and robust mechanical stability of geometrically confined Fe3N nanoparticles contribute to the excellent redox activities, stabilized solid-electrolyte-interphase film and cycling durability of Fe3N@NCNT.

Constructing Pr-doped CoOOH catalytic sites for efficient electrooxidation of 5-hydroxymethylfurfural

Electrocatalytic conversion of renewable biomass is emerging as a promising route for sustainable chemical production; hence it urgently calls for developing efficient electrocatalysts with low potentials and high current densities. Herein, a Pr-doped Co(OH)2 hexagonal sheet (Pr/Co = 1/9, in mole) is synthesized by electrodeposition as highly performant catalyst for 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) to produce 2,5-furandicarboxylic acid (FDCA). This novel and low-cost catalyst possesses a rather low onset potential of 1.05 V (vs. RHE) and requires only 1.10 V (vs. RHE) to reach a current density of 10 mA cm−2 for HMFOR, significantly outperforming Co(OH)2 benchmark (i.e., 210 mV higher to reach 10 mA cm−2). The origin of Pr promotion effect as well as the evolution of CoOOH catalytic sites and HMFOR process has been deeply elucidated by physical characterizations, kinetic experiments, in situ electrochemical techniques, and theoretical calculations. The unique Pr-ameliorated CoOOH active centers enable 100% conversion of HMF, 99.6% selectivity of FDCA, and 99.7% Faraday efficiency, with a superior cycling durability toward HMFOR. This can be one of the most outstanding results for Co-based HMFOR catalysts to date in the literature. Thereby this work can help open up new horizons for constructing novel and efficient Co-based electrocatalysts by the utilization of lanthanide elements.

A hierarchical Cu2SnO4@NiCo-LDH nanofilament structure as a new-potent electrode for energy storage

Our research continues to explore innovative, efficient electrode materials and new production processes for electrochemical devices. Supercapacitors remain at the forefront of energy storage solutions, thanks to their exceptional power density, cycling durability, and mechanical robustness. For the first time, we have developed a hierarchical Cu2SnO4@NiCo-LDH nanocomposite using a straightforward hydrothermal technique coupled with an annealing process on a nickel foam substrate. This study introduces the novel Cu2SnO4@NiCo-LDH (CSO@NC-LDH) material, distinguished by its unique nanofilament structure and impressive electrochemical properties, including a high specific capacitance of 2791.5 F g−1 at 1 A g−1. Additionally, we created an asymmetric supercapacitor using CSO@NC-LDH for the positive electrode and activated carbon (AC) for the negative electrode. This system showcases an outstanding energy density of 108.67 Wh kg−1 and a notable power density of 1.05 kW kg−1 at an operating voltage of 1.6 V. These exciting results highlight the promising potential of CSO@NC-LDH nanofilaments as advanced electrodes for next-generation energy storage devices.

N/O-bridge stimulated robust binding energy and fast charge transfer between carbon nanofiber and NiCo LDH for advanced supercapacitors

Layered double hydroxide (LDH)-carbon composites effectively mitigate the inherent issues of agglomeration and poor conductivity in LDH. However, the weak binding energy and insufficient charge transfer capability between LDH and carbon substrate significantly compromise the active substance loading, cyclic stability and practical capacity of the composites. Herein, N/O co-doping porous carbon nanofibers (NOPCNFs) are first prepared by blending diminutive zinc imidazolate framework-8 nanoparticles with polyacrylonitrile for electrospinning, and then densely packed NiCo LDH nanosheets are homogeneously anchored on NOPCNFs to form NiCo LDH@NOPCNFs heterostructure via a hydrothermal method. The experimental findings and density functional theory calculation results indicate that N/O atoms exhibit robust binding forces with metal atoms through enhanced electrostatic adsorption and p-d covalent hybridization, which facilitates the nucleation and development of NiCo LDH on carbon nanofibers. Meanwhile, these heteroatoms also serve as the bridge for electron transfer from NiCo LDH to NOPCNF, leading to a strong interfacial electric field, thus accelerating charge transfer behaviors. Benefitting from the synergistic interaction between NiCo LDH and NOPCNF, the obtained NiCo LDH@NOPCNFs demonstrate an elevated mass loading of active substance (55 wt%), an impressive specific capacitance of 1340 F/g at 1 A/g (based on the mass of NiCo LDH, 2463 F/g), and good cyclic durability for 5000 cycles. Moreover, an all-solid-state asymmetric supercapacitor using NOPCNFs and NiCo LDH@NOPCNFs shows promising practical application prospects. This work gives insights into the important influence of heteroatom doping in carbon, and provides a feasible approach for the efficient integration of electroactive and carbon material.

NiSe nanoparticles anchored on hollow carbon nanofibers with enhanced rate capability and prolonged cycling durability for sodium-ion batteries

NiSe nanoparticles anchored on hollow carbon nanofibers with enhanced rate capability and prolonged cycling durability for sodium-ion batteries

Binder-free copper manganese sulfide nanoflake arrays electrodeposited on reduced graphene oxide-wrapped nickel foam as an efficient battery-type electrode for asymmetric supercapacitors

In the current study, 2D interconnected copper manganese sulfide (CMS) nanoflake arrays are successfully electrodeposited on nickel foam (NF) and reduced graphene oxide-coated NF (NF/rGO). A pulsed current electrodeposition method is used to prepare a uniform and homogeneous coverage of rGO on NF. By using rGO as a conductive carbon-based template, an ultrathin nanoflake structure of CMS with smaller dimensions and higher electrochemically active surface area (ECSA) is achieved. The results reveal the battery-type behavior of the as-synthesized CMS electroactive materials. At a current density of 5 A g−1 this electrode delivers a significant specific capacity of 667 C g-1 and maintained a considerable proportion of its initial capacity, with a retention value of 83.2 % even after undergoing 3000 charge/discharge cycles. In addition, an asymmetric supercapacitor is fabricated by setting up the synthesized NF/rGO/CMS sample as the positive electrode and activated carbon as the negative electrode. The constructed device not only delivers an impressive energy density of 63.3 Wh kg-1 accompanied by an outstanding power density of 11214.5 W kg−1, but also exhibits a considerable cycling durability, enduring only a 12 % decline in specific capacitance after 3000 charge/discharge cycles at a current density of 5 A g−1.

Novel NH4V4O10-Reduced Graphene Oxide Cathodes for Zinc-Ion Batteries: Theoretical Predictions and Experimental Validation

This investigation explores the potential of enhancing aqueous zinc-ion batteries (AZIBs) through the introduction of a novel cathode material, NH4V4O10 (NVO), combined with reduced graphene oxide (rGO). Utilizing Density Functional Theory (DFT), it was hypothesized that the incorporation of rGO would increase the interlayer spacing of NVO and diminish the charge transfer interactions, thus promoting enhanced diffusion of Zn2+ ions. These theoretical predictions were substantiated by experimental data acquired from hydrothermal synthesis, which indicated a marked increase in interlayer spacing. Significantly, the NVO–rGO composite exhibits remarkable cyclic durability, maintaining 95% of its initial specific capacity of 507 mAh g−1 after 600 cycles at a current density of 5 A g−1. The electrochemical performance of NVO–rGO not only surpasses that of pristine NVO but also outperforms the majority of existing vanadium oxide cathode materials reported in the literature. This study underscores the effective integration of theoretical insights and experimental validation, contributing to the advancement of high-performance energy storage technologies.

Ex Situ Synthesis of Ti3C2@Fe-Ni-NC Heterostructure Towards an Efficient Bifunctional Electrocatalyst for High-Performance Zinc-Air Batteries

Zinc-air batteries (ZABs) with sustainable electrocatalysts have seen a lot of efforts to address oxygen reaction challenges to increase their lifespan and energy efficiency. Metal-organic frameworks (MOFs) and their derived materials are potential bifunctional electrocatalysts for addressing the oxygen reactions kinetics. However, under operational circumstances, MOFs and derived materials typically exhibit subpar electrochemical and conductivity. In this study, embedding MOF derived FeNi-N-C porous material in a few layer MXene nanosheets was effective strategy, enabling adequate conductivity, stability, and exposure number of active sites with better electrocatalytic activity towards oxygen reduction and oxidation reactions (ORR and OER). The resulting FeNi-NC@Ti3C2 hybrid exhibits notable bifunctional activities with a half-wave potential of 0.85 V and a low overpotential of 1.56 V, remarkable long-term cycle durability, as well as strong alcohol tolerance in an alkaline electrolyte. In addition, there is conductive MXene scaffold to achieve the highest ORR and OER activities with an ΔE value of 0.70 V. Furthermore, the FeNi-NC@Ti3C2 air-cathode-based assembled ZAB exhibits remarkable long-term cycling stability at 10 mA cm-2, a peak power density of 201 mW cm-2, and a high open circuit voltage (OCV) of 1.5 V. Ti3C2 MXene nanosheets provide a synergistic effect between two different materials in addition to protecting the surfaces of composite. This work provides a useful technique for enhancing ZAB's oxygen redox reactions, which could be used to aid in the development of efficient MOF@MXene based catalysts for electrochemical energy reactions.

Multi-Stage Engineered Co-Free Li[Ni1-X-Y Ti x Al y ]O2 Cathode for High-Energy Li-Ion Batteries

Since the global blueprint for carbon net zero emissions has been drawn, a part of the internal combustion engine (ICE) market share of vehicles has been continually shifting toward electric powered public and personal transportation. However, the serious remaining challenges regarding the price and performance issues of lithium-ion batteries (LIBs), which are the primary power source for electric vehicles (EVs), have impeded the large-scale adoption of EVs. Solving the affordability issue of current layered cathodes requires reducing the reliance on Co, which is extremely expensive with supply uncertainty. The aim of developing Co-poor or Co-free cathodes has led to an interest in LiNiO2 (LNO).1 LNO is one of the most promising cost-effective Co-free cathodes for LIBs because the cathode can achieve a high specific capacity of over 250 mAh g-1 with a typical upper voltage of 4.3 V versus Li/Li+. However, its poor cycling durability and thermal instability make its practical use difficult.2 In this study, we propose a highly stable Co-free Ni-enriched layered cathode based on LNO through a new doping strategy that incorporates heteroelements at different doping stages, i.e., the introduction of Ti during Ni(OH)2 synthesis and doping excess amounts of Al during the lithiation step. In combination with cathode surface protection, i.e., electrolyte modification or cathode surface coating, the proposed cathode retains 72.0% of its initial capacity after 3,500 cycles, which is the state-of-the-art for Co-free layered cathodes. Reference s : [1] M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski, J. Janek, Angew. Chem. Int. Ed., 58 (2019) 10434-10458.[2] H.-J. Noh, S. Youn, C.S. Yoon, Y.-K. Sun, J. Power Sources, 233 (2013) 121-130.

Single atomic Fe-dispersed hollow carbon spheres coated with Co3O4 synergistically catalyze oxygen reduction and oxygen evolution reactions

It is highly expected to construct an efficient electrocatalyst having dual active sites that can simultaneously catalyze both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in Zn-air batteries (ZABs). In this study, a new core-shell nanostructure (Co3O4/Fe-N4/HCS) consisting of single atomic Fe (Fe-N4)-dispersed hollow carbon spheres (Fe-N4/HCS) coated with Co3O4 nanoparticles (NPs) were successfully synthesized with SiO2 templates by a coating-polymerization-etching preparation strategy. Benefit from a synergistic effect of Co3O4 and Fe-N4 dual active species with unique HCS structure, Co3O4/Fe-N4/HCS displayed outstanding activity in both ORR (half-wave potential = 0.88 V) and OER (overpotential at 10 mA cm−2 = 0.33 V), respectively. Meanwhile, compared to Co3O4/Fe-N4/C with Co3O4 NPs on Fe-N4/C, Co3O4/Fe-N4/HCS with Co3O4 NPs on Fe-N4/HCS exhibits a higher stability during electrochemical processes depending on the stronger interaction between the Co3O4 NPs and atomic dispersed Fe-N4 sites embedded in unique HCS structure. Particularly, the ZABs fabricated by Co3O4/Fe-N4/HCS demonstrates a higher specific capacity (688.7 mAh gZn−1) and superior cycling durability over 80 h. The presence of the electron transfer from Co3O4 to Fe-N4 in Co3O4/Fe-N4/HCS, enables Fe-N4 bonded carbon electron deficiency. This promotes the deposition of Co3O4 NPs and enhances metal-HCS support interactions, which combined with a protecting effect of hollow carbon spherical shell on Co3O4 NPs inside the shell, achieving excellent catalytic stability. This research introduces a novel approach to design dual active sites as high-performance bifunctional ORR/OER catalysts.

Fast Responsive and High-Strain Electro-Ionic Soft Actuator Based on the 3D-Structure MXene-EGaIn/MXene Bilayer Composite Electrode.

Electro-ionic soft actuators have garnered significant attention owing to their promising applications in flexible electronics, wearable devices, and soft robotics. However, achieving high actuation performance (large bending strain and fast response time) of these soft actuators under low voltage has been challenging due to issues related to ion diffusion and accumulation. In this study, an electro-ionic soft actuator is fabricated using Ti3C2Tx MXene and eutectic gallium-indium (EGaIn) composite material as the bilayer electrode and methylammonium formate/1-ethyl-3-methylimidazolium tetrafluoroborate/poly(vinylidene fluoride) (MAF-EMIMBF4/PVDF) as the ionic liquid-type electrolyte. The research results indicate that the prepared soft actuator exhibits excellent actuation performance with a peak-to-peak displacement of 35 mm and a bending strain of 0.69% (a peak-to-peak strain of 1.38%) under a low voltage (3 V). The electro-ionic soft actuator shows a wide frequency range (0.1-10 Hz), fast response time (0.35 s), and a rise time of 7.5 s. Furthermore, it demonstrates good cyclic durability, with a retention rate of 92.5% of its performance for 10 000 cycles. These excellent performances are attributed to the 3D structure of the Ti3C2Tx-EGaIn/Ti3C2Tx bilayer composite electrode, as well as the characteristics of the low viscosity, high conductivity, small ion volume, and larger volume difference between cations and anions in MAF ionic liquid. The high-performance electro-ionic soft actuator can be used in various fields such as artificial muscles, tactile devices, and soft robots.

Synthesis of polyhedral Pt-Pd-Ni nanobelts regulated by W(CO)6 and applied as a highly performing oxygen reduction reaction electrocatalyst

Pt-Pd-Ni polyhedral nanobelt (PNBs) composite catalysts are synthesized in presence of tungsten hexacarbonyl [W(CO)6] by a simple solvothermal method, combining both higher specific surface area and more index active site than the corresponding single-structure catalysts. The thermal decomposition of W(CO)6 plays a crucial role in the morphology formation. The tenuous composite with a moderate nanobelt width of 7.46 nm formed after heating for 6 h (Pt-Pd-Ni PNBs2) shows better ORR performance and durability than the ternary (Pt-Pd-Ni) and binary (Pt-Pd) single structures. It exhibits a mass activity of 1.49 (A mgPt−1), which only degrades by about 10.63 % after 50,000 durability cycles. The metal regulatory effects induced by the carbonyl compounds cause the contraction of the Pt-Pt bonds. Density functional theory calculations indicate that the compressive strain of Pt-Pd-Ni PNBs2 leads to a decrease in the d-band center and overpotential negatively shifted, thus provide a more sufficient and faster ORR proceeding process in thermodynamics, facilitating a higher energy conversion efficiency.

Engineering of active site coupling to facilitate interatomic charge transfer for bifunctional oxygen electrocatalysis

Interatomic charge transfer emerges as a robust technique for enhancing catalytic efficacy in key energy reactions, specifically the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Despite its potential, advancing simultaneous improvements in reversible oxygen catalysis pose considerable challenges. Herein, we detailed an active site coupling engineering method to create a CoCu@NSC bifunctional oxygen electrode. In this configuration, OER-active Cu sites were alloyed with ORR-active Co within a N/S-doping carbon nanobox. This arrangement yielded a half-wave potential of 0.924 V for ORR, alongside an overpotential of η10 = 356 mV for OER. The fabricated CoCu@NSC cathode yielded a discharge capacity of 768 mAh/gZn, a peak power density of 295 mW/cm2, and extensive cycling durability. Work function assessments indicated that the chemical integration of Co and Cu components at the atomic level promoted interfacial charge redistribution, effectively optimizing the adsorption-desorption dynamics of intermediates at the active sites, thereby substantially enhancing the catalytic performance for both OER and ORR. Additionally, doping with N/S species enhanced the conductivity of the hollow carbon matrix, facilitating more effective mass and charge transport pathways. These insights illuminate a compelling approach for the design and synthesis of effective bifunctional oxygen electrodes that is pivotal for advanced energy storage advice.

Hydrogen accelerated nanopore nucleation, crack initiation and propagation in the Ni–Co superalloys

Influence of hydrogen at pressures up to 35 MPa (and absorbed hydrogen with concentration up to 32,7 ppm) on the nanopore nucleation, crack initiation and propagation in Ni–Co superalloys for disk application with different chemical composition and tempering modes has been investigated. It was established that under the influence of gaseous hydrogen, the tensile strength, true fracture stress, relative elongation, and reduction of area of disk alloys samples decrease both at room and close to operating temperatures (1073 K). The cyclic durability of the samples under the influence of prolonged exposure to high pressures and temperatures in the hydrogen gas environment decreases by about 3 times.We have discussed the mechanisms of hydrogen-assisted nickel-cobalt superalloys fracture on mesa-, macro-, micro-, and nano-levels.

Interfacial coordination effects for uniform and reversible zinc anode deposition

The instability resulting from side reactions including zinc dendrites and hydrogen evolution observed at the interface between the anode and electrolyte has impeded the progress of aqueous zinc-ion batteries (AZIBs). In this study, 1,5-naphthalenedisulfonic acid (NA) is introduced to guide homogeneous and reversible deposition behavior of Zn2+ based on metal-coordination chemistry. Theoretical calculations combined with experiments demonstrate that the strong coordination effect between S and Zn results in the adsorption of a NA layer on the anode surface, suppressing side reactions while facilitating the uniform deposition of Zn2+. By and large, the inclusion of NA extends the cycling stability to nearly 3600 h at a current density of 0.5 mA cm−2 (0.5 mAh cm−2), and it enables durable cycling for 200 h even at a high current density of 20 mA cm−2 (10 mAh cm−2). The Zn||VNNC full battery can be cycled stably for 700 cycles at 5 A g−1 at a low N/P ratio (2.58). The consequence caters a new perspective on the coordination effect at the interface for zinc anodes to achieve high reversibility in AZIBs and ZICs.

Room-temperature synthesis of VO(OH)2 as a high capacity cathode material for aqueous zinc ion batteries

The development of satisfactory cathodes plays a key role in the widespread utilization of aqueous zinc ion batteries. Cathode materials with high specific capacity and long cycling life are still urgently needed for aqueous zinc ion batteries. Herein, a new cathode material VO(OH)2 is synthesized by a facile room-temperature precipitation approach, and its electrochemical characteristics and structural evolution process are investigated. Benefiting from its intrinsic electrochemical activity, the VO(OH)2 cathode exhibits a remarkable specific capacity of 488 mAh g−1 at 0.1 A g−1, retains a high capacity of 219.1 mAh g−1 at the increased current density of 10 A g−1, and provides a maximum energy density of 439.2 Wh kg−1. In addition, when subjected to a 12,000 cycles charge/discharge test at 10 A g−1, the cathode retains a capacity of 185.8 mAh g−1, highlighting durable cycling performance. The structural evolution analysis reveals that of VO(OH)2 cathode may be in-situ transformed to an amorphous vanadium oxide V2O5-x in the first charging process, which could reversibly intercalate/deintercalate zinc ions. This research supplies a promising cathode material for aqueous zinc ion batteries and enhances understanding of vanadium oxyhydroxide in metal ion storage.

Soft carbon filled in expanded graphite layer pores for superior fast-charging lithium-ion batteries

The slow kinetics and lithium deposition of graphite anode are considered the key limitations of fast-charging lithium-ion batteries. Expanded graphite has shown tremendous potential for the improvement of rate performance due to its massive active sites released and lifted lithium storage platform. However, the risk of structural collapse caused by fast charging will reduce the cycling life of the expanded graphite anode. Herein, this study designed a stable structure of expanded graphite by filling its layer pores with pitch-derived soft carbon (EGC). The honeycomb-like EGC is a great fast-charging candidate material with rich active sites, enlarged ion transport channels, and efficient ion transport interfaces. As the experimental and simulation results, the EGC electrode demonstrated significantly fast lithium-ions storage kinetics and durable long cycle life, compared to commercial fast-charging graphite anode. Notably, the EGC//LiNi0.8Co0.1Mn0.1O2 full cell delivered a superior fast-charging and stability performance (near 20 min charging for 80 % State of Charge). The simple multifunctional modification strategy for graphite anode in this work provides a new approach for superior fast-charging lithium-ion batteries.