钾离子电池的研究进展及展望

锂离子电池（LIBS）已经广泛应用到便携式电子产品和电动汽车上.然而，随着锂资源的开采使用，锂离子电池的成本也在逐渐增加.相比之下，地壳中较高的钾含量使得钾离子电池（KIB）成本相对较低.进而，钾离子电池作为一种新型低成本储能器件受到了广泛关注.但钾离子的半径较大，导致充放电过程中，离子嵌入/脱出的动力学性能较差.因此，电池电极材料的选择面临着新的挑战.在对钾离子电池电极材料进行分类和总结的基础之上，重点介绍了石墨及各种形式的碳材料、过渡金属氧化物、合金类等负极材料以及普鲁士蓝、层状金属氧化物、聚阴离子型化合物等正极材料的研究进展，并对钾离子电池的发展进行了展望，以期对高性能钾离子电池的发展提供新思路.

Research progress and prospect of potassium-ion batteries

Development and utilization of renewable energy sources have gain great progress in recent years, which lead to increasing demands for large scale energy storage systems. Lithium-ion batteries have been widely used in portable electronic devices and electric vehicles. However, with the exploitation of the Earth’s lithium resources, the cost of lithium-ion batteries is gradually increasing. In contrast, the higher terrestrial potassium content promises inexpensive potassium-ion batteries, and the chemical properties of potassium and lithium ions are similar. Meanwhile, the low redox potential of K promises a high working voltage of potassium ion batteries. Thus, potassium-ion batteries have attracted considerable attention as a capable battery technology. However, the large radius of the potassium ion leads to unsatisfactory ion intercalation and extraction behavior during charging and discharging processes, resulting in poor cycling performance, unsatisfactory rate ability, and low capacity. The challenge remains to explore capable electrode materials for potassium-ion batteries to achieve a high energy density and power density. This review summarizes the anode and cathode materials of potassium-ion batteries in recent reports, including the research progress of graphite and other carbon materials, transition metal oxides/sulfides, alloys, and other anode materials, as well as Prussian blue, layered metal oxides, and polyanionic compound cathode materials, which will provide new ideas for developing high-performance potassium-ion batteries. We also discuss the potassium ion storage mechanism in these electrode materials. This review also demonstrates the approaches (nanotechnology, heteroatom doping, carbon coating, composite fabrication) to further improve the electrochemical performance of the cathode and anode. In addition, we point out the key factors for potassium ion batteries performance, such as the design of anode materials, exploitation of novel cathode materials, and optimization of full potassium ion cells fabrication, which would provide new thought for the development of potassium ion batteries with high performances.