Nano/Micro-Structured Si/C Anodes with High Initial Coulombic Efficiency in Li-Ion Batteries.

One of the major challenges for designing high-capacity anode materials is to combine both Coulombic efficiency and cycling stability. Herein, nano/micro-structured Si/C composites are designed and synthesized to address this challenge by decreasing the specific surface area and improving the tap density of Si/C materials. An ultrahigh initial Coulombic efficiency of 91.2 % could be achieved due to a proper particle size, low specific surface area, and optimized structure. The nano/micro-structured Si/C anodes exhibit excellent cycling stability with 96.5 % capacity retention after 100 cycles under a current density of 0.2 A g(-1) .