Novel bread-like nitrogen-doped carbon anchored nano-silicon as high-stable anode for lithium-ion batteries

Abstract Nano core-shell silicon/carbon (Si/C) composites can efficiently enhance the conductivity and accommodate the volume change for Si. However, new challenges of big specific surface area and high interparticle resistance still weaken its advantages. In order to solve the above problems, we prepared a micron bread-like Si-based composite with high Si content in it, in which buffer space in clustered core-shell units are used to relieve the stress caused by volume expansion, and the N-doped carbon skeleton derived from ZIF-8 is applied to enhance the electrical contact between adjacent core-shell units. Due to the stable bread-like structure, the integrity of stable solid electrolyte interphase layer is maintained, and the lower external surface area retains the coulombic efficiency as high as 95.5% during cycling. The specific capacities of the obtained composite are 1155 mAh g-1 at 2 A g-1 and 815 mAh g-1 at 5 A g-1 in rate performance. After long-term cycling of 500 cycles, the composite still maintains specific capacities of 1109 mAh g-1 at 3 A g-1 and 804 mAh g-1 at 5 A g-1 with ICE of 65.55% in the first three activated cycles.