Low-coordination water Prussian white as cathode for high-performance potassium-ion batteries

Prussian whites (PWs) with a three-dimensional framework can accommodate the insertion and extraction of ions with large radius, which have been widely used in potassium ion batteries. However, PWs show the poor cycling performance and inferior rate ability because of high coordinated water. In this work, PWs with different water content were synthesized via a coprecipitation method by controlling the reaction temperature. The sample with low-coordination water prohibits the best electrochemical performance. It shows a high capacity of 120.5 mAh/g at 100 mA/g for potassium-ion batteries (KIBs). It also exhibits a good rate performance, displaying a capacity of 73.2 mAh/g at 500 mA/g.