▎ 摘　　要

Potassium-ion batteries (PIBs) as a substitute for lithium-ion batteries have aroused widespread attention and have been rapidly developed. In the positive electrode materials, polyanionic compound has a high working voltage and large reversible capacity on account of its distinct framework and the strong inducing effect of the anionic group. Herein, a KVPO4F/reduced graphene oxide (KVPF/rGO) hybrid was fabricated via a simple multi-step approach as the polyanionic cathode material for PIBs. Profiting from the small size of KVPF nanoparticles and their uniform distribution in the rGO framework, the as synthesized KVPF/rGO hybrid manifests a large discharge capacity of 103.2 mAh g(-1) with an outstanding energy density of 436.5 Wh kg(-1). Through rGO decoration, the hybrid also demonstrates remarkable rate and cycling properties. By employing ex-situ X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques, the potassium storage mechanism of KVPF was clearly revealed. The facile preparation procedure and superior properties endow it great application prospects in large-scale energy storage. (c) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.