3D porous V2O5 architectures for high-rate lithium storage

The discovery of novel electrode materials promises to unleash a number of technological advances in lithium-ion batteries.V2O5 is recognized as a high-performance cathode that capitalizes on the rich redox chemistry of vanadium to store lithium.To unlock the full potential of V2O5,nanotechnology solution and rational electrode design are used to imbue V2O5 with high energy and power density by addressing some of their intrinsic disadvantages in macroscopic crystal form.Here,we demonstrate a facile and environmental-friendly method to prepare nanorods-constructed 3D porous V2O5 architectures(3 D-V2O5)in large-scale.The 3D porous architecture is found to be responsible for the enhanced charge transfer kinetics and Li-ion diffusion rate of the 3D-V2O5 electrode.As the result,the 3D-V2O5 surpasses the conventional bulk V2O5 by showing enhanced discharge capacity and rate capability(delivering 154 and 127 m Ah g^-1 at 15 and 20 C,respectively).

Self-assembled V2O5 interconnected microspheres produced in a fish-water electrolyte medium as a high- performance lithium-ion-battery cathode

Interconnected microspheres of V2Os composed of ultra-long nanobelts are synthesized in an environmental friendly way by adopting a conventional anodization process combined with annealing. The synthesis process is simple and low-cost because it does not require any additional chemicals or reagents. Commercial fish-water is used as an electrolyte medium to anodize vanadium foil for the first time. Electron microscopy investigation reveals that each belt consists of numerous nanofibers with free space between them. Therefore, this novel nanostructure demonstrates many outstanding features during electrochemical operation. This structure prevents self-aggregation of active materials and fully utilizes the advantage of active materials by maintaining a large effective contact area between active materials, conductive additives, and electrolyte, which is a key challenge for most nanomaterials. The electrodes exhibit promising electrochemical performance with a stable discharge capacity of 227 mAh·g^-1 at 1C after 200 cycles. The rate capability of the electrode is outstanding, and the obtained capacity is as high as 278 at 0.5C, 259 at 1C, 240 at 2C, 206 at 5C, and 166 mAh·g^-1 at 10C. Overall this novel structure could be one of the most favorable nanostructures of vanadium oxide-based cathodes for Li-ion batteries.

Fast interfacial electrocatalytic desolvation enabling lowtemperature and long-cycle-life aqueous Zn batteries

Low-temperature zinc batteries(LT-ZIBs)based on aqueous electrolytes show great promise for practical applications owing to their natural resource abundance and low cost.However,they suffer from sluggish kinetics with elevated energy barriers due to the dissociation of bulky Zn(H2O)62+solvation structure and free Zn2+diffusion,resulting in unsatisfactory lifespan and performance.Herein,dissimilar to solvation shell tuning or layer spacing enlargement engineering,delocalized electrons in cathode through constructing intrinsic defect engineering is proposed to achieve a rapid electrocatalytic desolvation to obtain free Zn2+for insertion/extraction.As revealed by density functional theory calculations and interfacial spectroscopic characterizations,the intrinsic delocalized electron distribution propels the Zn(H2O)62+dissociation,forming a reversible interphase and facilitating Zn2+diffusion across the electrolyte/cathode interface.The as-fabricated oxygen defect-rich V2O5 on hierarchical porous carbon(ODVO@HPC)electrode exhibits high capacity robustness from 25 to20℃.Operating at-20℃,the ODVO@HPC delivers 191 mAh g-1 at 50 A g-1 and lasts for 50000 cycles at 10 A g-1,significantly enhancing the power density and lifespan under low-temperature environments in comparison to previous reports.Even with areal mass loading of-13 mg cm2,both coin cells and pouch batteries maintain excellent stability and areal capacities,realizing practical high-performance LT-ZIBs.