The development and application of high performance potassium ion batteries (PIBs) is a major demand for China's strategic emerging industries, and it is also a new system and direction for the development of energy storage secondary batteries. However, the current research on PIBs is still in its initial stage, and still faces the challenges of slow diffusion kinetics, unclear transport mechanism, rapid capacity decay and difficulty in revealing the intrinsic decay mechanism. This paper summarizes the latest research results of the National Natural Science Foundation of China (NSFC) project "Surface/Interface Tuning and In Situ Interaction Mechanism of Hierarchical Mesoporous Nanowire Cathodes for Potassium Ion Battery", systematically describes the key scientific problems and technical bottlenecks in PIB research, and points out the efficient strategies to solve these problems and bottlenecks.