Authors: Xiong Liu, Wentao Ni, Yuan Wang, Yongle Liang, Banghui Wu, Guobao Xu, Xiaolin Wei, Liwen Yang
Published: 2022-01-17
Source: Full article
AbstractLayered vanadium oxides have great potential as cathode materials for recently surged aqueous zinc‐ion batteries (AZIBs). However, achieving high energy/power densities simultaneously is challenging, and side reactions related to more frequently than disclosed Zn2+/proton co‐insertion mechanism aggravate stability concerns. Herein, an engineered binder‐free cathode configuration based on water‐processable and high packing‐density sheet‐shaped composites of carbon nanotubes network, surface poly(3,4‐ethylenedioxythiophene) (PEDOT) bridging coating, and ultrasmall PEDOT‐intercalated V2O5 nanoflakes is developed, and therein, large pseudocapacitance via predominant (≈91%) Zn2+ intercalation is revealed. Besides competitive gravimetric/areal capacity, the binder‐free cathodes exhibit high volumetric capacity of 1106.1 mAh cm−3 and high‐rate capability of 180.0 mA g−1 at 30 A g−1 as well as long‐cycling stability. Such combined level of performance and unwanted reaction mechanism are attributed to the contained multiscale material/electrode design formula from crystal structure modification to 3D architecture construction of whole electrode, which endows the binder‐free cathodes with abundant accessible sites for Zn2+ storage, but the least hydroxyl terminated surface for H+ insertion, as well as highly conductive network for electron transfer and fast Zn2+ diffusion kinetics throughout the electrode. Combined with scalable fabrication protocols, this study opens up great opportunities for high‐performance vanadium oxide cathodes practically applicable to AZIBs.