Enhanced initial coulombic efficiency of lithium-ion battery silicon–carbon anodes with phosphorus doping

Abstract

Enhancing the initial coulombic efficiency (ICE) and suppressing the volume expansion of silicon-based anodes remain a challenge. In this work, we propose a strategy for incorporating phosphorus (P) atoms into silicon–carbon composites. Through mechanical ball milling and high-temperature calcination, the P atoms were uniformly distributed within the carbon layer and silicon particles. This approach not only reduced the interfacial charge transfer resistance by ∼70% but also increased the Li⁺ diffusion capability by ∼11%. As a result, an ICE of 88.6% and an initial discharge capacity of 2730 mAh g⁻¹ were recorded. Moreover, the reversible capacity remained at 1108 mAh g⁻¹ at 1 A g⁻¹ after 150 cycles, and the reversible capacities at 0.1 A g⁻¹, 0.5 A g⁻¹, 1 A g⁻¹ and 2 A g⁻¹ were 3204 mAh g⁻¹, 1966 mAh g⁻¹, 1510 mAh g⁻¹ and 798 mAh g⁻¹, respectively. The results indicated that P-doping is a promising way to enhance the ICE of silicon-based anodes.