K0.67Ni0.17Co0.17Mn0.66O2: A cathode material for potassium-ion battery

A novel layered ternary material K 0.67 Ni 0.17 Co 0.17 Mn 0.66 O 2 has been fabricated via a co-precipitation assisted solid-phase method and further evaluated as a cathode for potassium-ion batteries for the first time. Highly reversible K + intercalation/deintercalation is demonstrated in this material. It delivers a reversible capacity of 76.5   mAh/g with average voltage of 3.1   V and shows good cycling performance with capacity retention of 87% after 100   cycles at 20   mA/g. This work may give a new insight into developing cathode materials for potassium-ion batteries.