Study of Binder Effect on the Lithium Storage Kinetics of Copper Phosphide Nanotube Anode

Copper phosphide (CP) stands out as a promising anode material for lithium-ion batteries due to its high theoretical capacity (1281 mAh g-1). However, the fast capacity decay of copper phosphide poses a significant challenge due to its huge volume change. Optimization of binder selection presents an effective way to harness the high lithium storage capacity of copper phosphide. In this study, copper phosphide nanotubes were synthesized using a hard template transformation method. The following investigation delved into the impact of different binders on the electrode structure and the lithium-ion storage performance of copper phosphide. Notably, employing polyacrylic acid (PAA) as a binder resulted in a stable capacity of 526.8 mAh g-1 over 400 cycles at 100 mA g-1 for the copper phosphide electrode. The remarkable lithium-ion storage property of the CP-PAA electrode is ascribed to the robust interaction between PAA and the P-O bond on the copper phosphide surface. This interaction not only mitigated volume expansion but also enhanced the kinetics of electrochemical reactions.