Improving the potassium storage capability of GeP5 anode material for sustainable potassium‐Ion batteries

GeP₅ anode materials have garnered significant attention for potassium-ion batteries (PIBs). The combination of their layered structure with high electrical conductivity and high theoretical capacity of 1888 mAh g⁻¹ renders them highly promising as anode materials for PIBs. However, severe volume changes and pulverization during cycling limit their practical application. To address these challenges, this study employed a scalable two-step high-energy ball milling process to synthesize GeP₅/C composite materials. This approach resulted in a carbon coating that chemically bonded with the GeP₅ core, enhancing the composite’s structural integrity. The carbon coating also facilitated efficient electron transport and accommodated volume changes during cycling. The optimized GeP₅/C-30 composite demonstrated exceptional cycling stability and rate performance. Even after 1000 cycles at a high specific current of 500 mA g⁻¹, the GeP₅/C-30 cell maintained a discharge capacity of 257.94 mAh g⁻¹ achieving a capacity retention of 66.81 %. It also demonstrated outstanding rate capability, delivering a specific capacity of 252.18 mAh g⁻¹ at a high specific current of 1500 mA g⁻¹. In addition, the GeP₅/C-30||KFe[Fe(CN)₆·xH₂O full cell also demonstrated excellent performance, retaining a high specific capacity of 271.09 mAh g⁻¹, corresponding to a capacity retention of 97.67 % after 200 cycles at a specific current of 300 mA g⁻¹. These findings offer a promising strategy for designing high-performance GeP₅-based anodes for PIBs and other energy storage applications.