Synthesis of V2O5·nH2O nanobelts@polyaniline core–shell structures with highly efficient Zn2+ storage

Abstract

Aqueous zinc-ion batteries (AZIBs) are regarded as attractive candidates for next-generation energy storage devices. Among various cathode materials, V2O5·nH2O (VOH) possesses a high theoretical capacity but poor cycle stability due to the susceptibility of its open structure to damage by the quick shuttling of Zn2+. Herein, the structural stability of VOH is directly improved by wrapping polyaniline (PANI) on the VOH nanobelts (VOH@PANI). As a cathode material for AZIBs, the VOH nanobelts@PANI core–shell structures exhibit an outstanding cycle stability of 98% after 2000 cycles at 2 A g−1. The improved conductivity and additional energy storage contribution of the PANI endow VOH@PANI with a specific capacity as high as 440 mAh g−1 at 0.1 A g−1, substantially higher than pure VOH (291 mAh g−1). At the same time, high energy and power densities of 349 Wh kg−1 and 3347 W kg−1 are achieved. This work not only demonstrates that p-type doped PANI coatings on VOH can boost the Zn2+ storage of VOH, but also provides a novel method to enhance cathode materials for high electrochemical performance.