An exploratory investigation of the high pressure β-V2O5 polymorph as 3 V cathode material for potassium-ion battery

Abstract

Electrochemical potassium-ion insertion in high pressure /high temperature (HP/HT) β-V2O5 polymorph is examined for the first time. Monoclinic HP/HT β-V2O5 delivers a high reversible capacity of 120 mAh g􀀀 1 at C/20 rate corresponding to the K0.8V2O5 composition, at an average discharge potential of 3.2 V vs. K+/K. A good cycling performance is achieved over at least 175 cycles at C/5 rate at room temperature, confirming HP/HT β-V2O5 is an efficient host material for K+ insertion-extraction reaction. First insight into the reversibility of the structural changes upon potassiation is given.