GeP5/C composite as anode material for high power sodium-ion batteries with exceptional capacity

Abstract

Red phosphorus (P) as anode materials for sodium ion battery has an obvious superiority in high theoretical capacity (2600 mAh/g), but its electrical conductivity is not ideal. Alloying red P and other elementary substance is an effective method to improve this situation. Here in, we synthesize a type of GeP5/C composite by high energy ball milling method, and use this composite as anode for sodium-ion battery. The structure morphology and electrochemical performance of the GeP5/C composite have been investigated in detail. The GeP5/C composite delivers a high first discharge capacity of 1368 mAh/g and a satisfactory initial coulumbic efficiency of 88.3% at a current density of 150 mA/g. Even at an ultrahigh current density of 5000 mA/g, it still delivers a higher discharge capacity of 839.6 mAh/g and better capacity retention of 59.2% over 30 cycles, compared with those of pure GeP5. The improved electrochemical properties of GeP5/C can be ascribed to the composite structure of GeP5 and carbon and favourable conductivity of GeP5/C.