Potassium ion batteries(PIBs)have attracted tremendous attentions due to the low cost,fast ionic conductivity in electrolyte and high operating voltage.Thanks to the achievements of lithium/sodium ion batteries and the advanced battery engineering technology,notable progress have been made for PIBs especially in recent three years.However,the research of PIBs are still at infant stage and general understanding the drawbacks of each parts(electrode materials or electrolytes)and proposing research strategies for overcoming problems are crucial in the exploration of suitable electrode materials and establishing electrode/cell assembly technologies for further development of PIBs.