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High-Performance Aqueous Zinc-Ion Batteries Enabled by Binder-Free and Ultrathin V2O5–x@Graphene Aerogels with Intercalation Pseudocapacitance
journal contributionposted on 2022-11-18, 17:38 authored by Fuyu Chen, Haoran Luo, Meng Li, Yujie Zheng, Minquan Zhou, Hao Gui, Yongsheng Xiang, Chaohe Xu, Xinlu Li, Ronghua Wang
As a result of the absence of solid-state diffusion limitation, intercalation pseudocapacitance behavior is emerging as an attractive charge-storage mechanism that can greatly facilitate the ion kinetics to boost the rate capability and cycle stability of batteries; however, related research in the field of zinc-ion batteries (ZIBs) is still in the initial stage and only found in limited cathode materials. In this study, a novel V2O5–x@rGO hybrid aerogel consisting of ultrathin V2O5 nanosheets (∼1.26 nm) with abundant oxygen vacancies (Vö) and a three-dimensional (3D) graphene conductive network was specifically designed and used as a freestanding and binder-free electrode for ZIBs. As expected, the ideal microstructure of both the material and the electrode enable fast electron/ion diffusion kinetics of the electrode, which realize a typical intercalation pseudocapacitance behavior as demonstrated by the simulation calculation of cyclic voltammetry (CV), ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and first-principles density functional theory (DFT) calculation. Thanks to the elimination of solid-state diffusion limitation, the V2O5–x@rGO electrode delivers a high reversible rate capacity of 153.9 mAh g–1 at 15 A g–1 and 90.6% initial capacity retention at 0.5 A g–1 after 1050 cycles in ZIBs. The intercalation pseudocapacitance behavior is also realized in the assembled soft-pack battery, showing promising practical application prospects.
state diffusion limitationnanosheets (∼ 1limited cathode materialsgraphene conductive networkabundant oxygen vacanciesray photoelectron spectroscopyinitial capacity retentionxrd ), xperformance aqueous zincion diffusion kineticsintercalation pseudocapacitance behavior9 mah g2 subion batteries enabled5 subx ion kineticsintercalation pseudocapacitancexps ),ray diffractionion batteriesinitial stagevo ̈)storage mechanismspecifically designedrelated researchrate capabilitypack batteryideal microstructuregreatly facilitatecyclic voltammetrycycle stabilityattractive chargeassembled softalso realized5 –<26 nm1050 cycles