Design of phosphorus-doped porous hard carbon/Si anode with enhanced Li-ion kinetics for high-energy and high-power Li-ion batteries

Abstract

With the rapid progress of portable electronics and electric vehicles, high-energy lithium-ion batteries (LIBs) with fast-charging technology are urgently required. Silicon (Si) is considered as the most promising anode candidate for high-energy LIBs but challenging to large-scale commercialization due to its huge volume change and poor conductivity. To develop high-capacity Si-based anode materials with enhanced lithium-ion diffusion and fast reaction kinetics, we design a novel high-Si-content Si/hard carbon composite via scalable methods. The combination between phosphorus-doped hard carbon with porous structure and uniformly distributed Si nanolayers effectively improve lithium-ion kinetics and mitigate the volume change of Si. As a result, the architecture delivers a reversible capacity of 1124 mAh/g at 0.1C and superior cycling stability with an 87.4% capacity retention after 200 cycles at 1C. The 1.5 A h pouch-type full-cell tests further demonstrate good cycling stability and high rate performance at 4C under an electrode density of 1.6 g cm−3 and areal capacity loading of 3.53 mAh cm−2. This work paves a new way for the rational design of Si-based anode materials for high-energy and high-power LIBs.