Melamine Polymerization Promotes Compact Phosphorus/Carbon Composite for High-Performance and Safe Lithium Storage.

ABSTRACT

Phosphorus is regarded as a promising material for high-performance lithium-ion batteries (LIBs) due to its high theoretical capacity, appropriate lithiation potential, and low lithium-ion diffusion barrier. Phosphorus/carbon composites (PC) are engineered to serve as high-capacity high-rate anodes; the interaction between phosphorus and carbon, long-term capacity retention, and safety problems are important issues that must be well addressed simultaneously. Herein, an in situ polymerization approach to fabricate a poly-melamine-hybridized (pMA) phosphorus/carbon composite (pMA-PC) is employed. The pMA hybridization enhances the density and electrical conductivity of the PC, improves the structural integrity, and facilitates stable electron transfer within the pMA-PC composite. Moreover, the pMA-PC composite exhibits efficient adsorption of lithium polysulfides, enabling stable transport of Li+ ions. Therefore, the pMA-PC anode demonstrates a high specific charging capacity of 1,381 mAh g-1 at 10 A g-1, and a great capacity retention of 86.7% at 1 A g-1 over 500 cycles. The synergistic effect of phosphorus and nitrogen further confers excellent flame retardant properties to the pMA-PC anode, including self-extinguishing in 2.5 s, and a much lower combustion temperature than PC. The enhanced capacity and safety performance of pMA-PC show potential in future high-capacity and high-rate LIBs.