Ultrasmall, Amorphous V<sub>2</sub>O<sub>3</sub> Intimately Anchored on a Carbon Nanofiber Aerogel Toward High-Rate Zinc-Ion Batteries
Huifa Shi, Jiakai Cao, Weiyi Sun, Guixia Lu, Hongbo Lan, Lei Xu, Zahid Ali Ghazi, Dinghui Fan, Zongyu Mao, Daliang Han, Wenbao Liu, S.T. Niu
Abstract
When considered as a cathode candidate for aqueous Zn-ion batteries, V 2 O 3 faces several problems, such as inherently unsuitable structure, fast structural degradation, and sluggish charge transport kinetics. In this paper, we report the synthesis of a V 2 O 3 intimately coupled carbon aerogel by a controllable ion impregnation and solid-state reaction strategy using bacterial cellulose and ammonium metavanadate as raw materials. In this newly designed structure, the carbonized carbon fiber network provides fast ion and electron transport channels. More importantly, the cellulose aerogel functions as a dispersing and supporting skeleton to realize the particle size reduction, uniform distribution, and amorphous features of V 2 O 3 . These advantages work together to realize adequate electrochemical activation during the initial charging process and shorter transport distance and faster transport kinetics of Zn 2+ . The batteries based on the V 2 O 3 /CNF aerogel exhibit a high-rate performance and an excellent cycling stability. At a current density of 20 A g –1, the V 2 O 3 /CNF aerogel delivers a specific capacity of 159.8 mAh g –1, and it demonstrates an exceptionally long life span over 2000 cycles at 12 A g –1 . Furthermore, the electrodes with active material loadings as high as 10 mg cm –2 still deliver appreciable specific capacities of 257 mAh g –1 at 0.1 A g –1 .