V2O5 Nanospheres with Mixed Vanadium Valences as High Electrochemically Active Aqueous Zinc-Ion Battery Cathode

Abstract

A V4+-V2O5 cathode with mixed vanadium valences was prepared via a novel synthetic method using VOOH as the precursor, and its zinc-ion storage performance was evaluated. The products are hollow spheres consisting of nanoflakes. The V4+-V2O5 cathode exhibits a prominent cycling performance, with a specific capacity of 140 mAh g−1 after 1000 cycles at 10 A g−1, and an excellent rate capability. The good electrochemical performance is attributed to the presence of V4+, which leads to higher electrochemical activity, lower polarization, faster ion diffusion, and higher electrical conductivity than V2O5 without V4+. This engineering strategy of valence state manipulation may pave the way for designing high-performance cathodes for elucidating advanced battery chemistry.

Rod-like anhydrous V2O5 assembled by tiny nanosheets as a high-performance cathode material for aqueous zinc-ion batteries

“…Multiple pairs of redox peaks can be observed, demonstrating a multistep Zn 2+ ion uptake/release process in V 2 O 5 cathode materials for AZIBs. [36][37][38][39] The CV curves of RA-V 2 O 5 at the 1 st cycle is different from that in the following cycles in terms of peak positions and proles, behind which the possible reason is the activation of V 2 O 5 . It is also seen that RA-V 2 O 5 exhibits more peaks than C-V 2 O 5 (Fig.…”

“…30 Among various vanadium-based materials, anhydrous V 2 O 5 is of particular interest owing to its simple conguration and high valence state of vanadium that enable more active sites and higher specic capacity. [32][33][34][35][36][37][38][39][40] That is, anhydrous V 2 O 5 is free of cations (e.g., Zn 2+ , Li + , Na + , K + , Mg 2+ , Ca 2+ ) and H 2 O molecules within its layers, thus possessing higher gravimetric and volumetric specic capacities than other vanadium-based materials in theory, while such characteristic also makes Zn 2+ ion uptake difficult due to the limited interlayer space. 34,41,42 For instance, porous V 2 O 5 nanobers prepared by electrospinning and subsequent calcination delivers merely 319 mA h g À1 at a rather low current density of 0.02 A g À1 , which is substantially lower than the theoretical specic capacity ($589 mA h g À1 based on the two-electron redox center of vanadium) of V 2 O 5 .…”

A Durable Na0.56V2O5 Nanobelt Cathode Material Assisted by Hybrid Cationic Electrolyte for High‐Performance Aqueous Zinc‐Ion Batteries

“…High initial discharge capacities of 417 mAh g −1 and 317 mAh g −1 are realized at 0.05 and 0.1 A g −1 with good cyclic performance (Figure S6). Besides, After activating for five cycles at 0.1 A g −1 , the cathode delivers an initial discharge capacity of 196 mAh g −1 at 0.5 A g −1 , and the capacity retention can reach to 84 % after 200 cycles. In particular, the rate capabilities of the NVO cathode in ZE and 0.5HCE were studied at the current densities of 0.1–2 A g −1 .…”

Silicon Nanoparticles Embedded in N‐Doped Few‐Layered Graphene: Facile Synthesis and Application as an Effective Anode for Lithium Ion Batteries

“…In addition, EIS tests were employed to more in‐deep understanding performed the pure Si and Si@NG‐21 electrodes to investigate the effect of graphene. As shown in Figure , Rs refers to the electrolyte resistance, Rct refers to the charge transfer resistance . The Rs of Si and Si@NG‐21 is 2.58 and 8.17. besides, the Rct of the Si and Si@NG‐21 decreases from 215.3 to 123.1 Ω.…”