Dual carbon layer coating of Cu and Ni doped silicon-based anode materials: Inhibiting volume expansion and enhancing conductivity

Silicon is regarded as the most promising anode material after graphite due to its high theoretical specific capacity (4200 mA·h·g⁻¹). However, the huge volume effect during the lithium insertion and extraction process causes silicon to be easily pulverized, which greatly affects its cycle stability. In this study, porous carbon skeleton silicon-based anode structures with volume expansion inhibition and high conductivity were prepared by doping metals Cu and Ni respectively through a combination of electrospinning and microelectronic 3D printing technologies. The results show that at a current density of 0.1 A·g⁻¹, the initial discharge specific capacities of the Si/Ni@C and Si/Cu@C electrodes are 1591 mA·h·g⁻¹ and 1603 mA·h·g⁻¹, respectively, with the first-cycle Coulombic efficiency both being 73%. After 100 cycles, the capacity of the Si/Ni@C electrode decreases from 1197 mA·h·g⁻¹ to 1143 mA·h·g⁻¹, with a capacity retention rate of 95%; The capacity of the Si/Cu@C electrode decreases from 1179 mA·h·g⁻¹ to 1075 mA·h·g⁻¹, with a capacity retention rate of 91%. In comparison, the metal-doped porous electrodes exhibit better cycle stability and conductivity.