Synthesis of VO·nHO nanobelts@polyaniline core-shell structures with highly efficient Zn storage.

Aqueous zinc-ion batteries (AZIBs) are regarded as attractive candidates for next-generation energy storage devices. Among various cathode materials, VO·nHO (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 Zn. 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. The improved conductivity and additional energy storage contribution of the PANI endow VOH@PANI with a specific capacity as high as 440 mAh g at 0.1 A g, substantially higher than pure VOH (291 mAh g). At the same time, high energy and power densities of 349 Wh kg and 3347 W kg are achieved. This work not only demonstrates that p-type doped PANI coatings on VOH can boost the Zn storage of VOH, but also provides a novel method to enhance cathode materials for high electrochemical performance.