AMORPHOUS CUSEP2/GRAPHENE COMPOSITES AS ANODE MATERIAL FOR ADVANCED POTASSIUM-ION BATTERY

The ternary amorphous CuSeP2 was designed and prepared as the anode material of potassium ion battery for the first time, and its electrochemical performance was also investigated. After ball-milling with commercial graphene powder, it is used as the anode material for potassium ion battery with reversible specific capacity up to 300 mAh g-1, and the corresponding initial coulombic efficiency is close to 60%. What’s more, the specific capacity remains above 150 mAh g-1 after 100 cycles at 200 mA g-1. When increasing the current density to 1000 mA g-1, the CuSeP2/graphene composites still has a potassium storage specific capacity of 100 mAh g-1. Our results show that the potassium storage mechanism of the ternary CuSeP2 anode material is a typical conversion reaction and the introduction of Cu can not only buffer the volume expansion during the subsequent electrochemical reaction, but also effectively enhance the electrochemical reversibility of potassium ion.本研究首次将三元非晶态CuSeP2设计并制备为钾离子电池负极材料，并对其电化学性能开展了系统研究。将其与商用石墨烯粉末进行球磨复合后，作为钾离子电池负极材料使用时，其可逆比容量可达300 mAh g⁻¹，对应的首次库仑效率接近60%。此外，在200 mA g⁻¹的电流密度下循环100次后，其比容量仍保持在150 mAh g⁻¹以上。当电流密度提升至1000 mA g⁻¹时，CuSeP2/石墨烯复合材料仍可实现100 mAh g⁻¹的储钾比容量。研究结果表明，三元CuSeP2负极材料的储钾机制属于典型的转化反应；而铜元素的引入不仅可缓冲后续电化学反应过程中的体积膨胀，还能有效提升钾离子的电化学可逆性。