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.
