Fluffy carbon-coated red phosphorus as a highly stable and high-rate anode for lithium-ion batteries

Abstract

Red phosphorus is considered as a potentially promising anode material for lithium-ion batteries owing to its high theoretical specific capacity of 2596 mA h g⁻¹ but facing the drawbacks of low conductivity and large volume change upon cycling. Herein, using fluffy carbon prepared from expanded rice, carbon-coated red phosphorus composites with a stable structure were synthesized via a simple route of ball milling the mixture of red phosphorus and fluffy carbon. The fluffy carbon was uniformly coated around the red phosphorus particles under shear force during the ball milling, and the formation of P–O–C bonds enhanced the contact between the red phosphorus and carbon. As a result, the fluffy-hard-carbon-coated red phosphorus with a high phosphorus loading of 80% exhibited superior electrochemical performance, i.e., a discharge capacity of 1655.9 mA h g⁻¹ (based on the composite) at 0.05C and excellent cycle stability and rate capability (∼1230 mA h g⁻¹ at 1C with 1000 cycles sustained at a capacity retention of 96%). This work not only demonstrates the superior design of the carbon-coated structure for a stable red phosphorus anode of lithium-ion batteries but also provides a simple, efficient, and easy-to-scale method to coat carbon onto the active materials.