Unlocking the side reaction mechanism of phosphorus anode with binder and the development of a multifunctional binder for enhancing the performance

Phosphorus is considered a prospective anode material for lithium-ion batteries because of its high theoretical capacity, high ionic conductivity, and appropriate lithiation potential. The research on the compatibilities of phosphorus anode is very significant for practical application. Herein, we focus on the compatibility of phosphorus anode with the binder and firstly reveal a vital phenomenon that there is a side reaction between the polyvinylidene fluoride (PVDF) and Li3P, leading to the damage of the binder's viscosity and the loss of active material. The side reaction is considered as a crucial reason for the capacity attenuation. Targeted against the newly discovered issue, we exploited a multifunctional binder of ammonium polyphosphate (APP), which is well compatible with Li3P, possessing predominant ionic conductivity, acting as obstruct layer to confine the shuttling of soluble lithium polyphosphides, improving the safety performance with the fire resistance, impairing environmental pollution with the green fabrication process. The superior rate capacity of 1031 mAh g-1 at 5 C and the excellent cycling stability with the capacity retention of 98.3% at 0.1 C for 200 cycles are achieved. With the good adaptability, simplicity, and low cost, the application of APP provides a feasible way for industrial application of phosphorus-based anode.

Automated summary

Phosphorus is considered a promising anode material for lithium-ion batteries due to its high theoretical capacity and other favorable properties. This study focuses on the compatibility between phosphorus anode and binder, revealing a crucial side reaction between PVDF and Li3P that hinders the performance of the battery. To address this issue, a multifunctional binder, ammonium polyphosphate, is developed and successfully improves the performance of the phosphorus-based anode with high rate capacity and excellent cycling stability.