A flexible and conductive connection introduced by cross-linked CNTs between submicron Si@C particles for better performance LIB anode

Abstract

To improve the inevitable capacity fading issues faced by traditional submicron Si@C electrodes used as anode materials in LIBs, a flexible and conductive connection design is proposed and realized by a solid-state growth approach. In this construction, Si@C is entangled into in situ synthesized carbon nanotube-based network to form a highly connective Si@C/CNTs composite. The interwoven carbon-nanotubes having tight linkages with Si@C contribute to ensure the charge transfer pathway within Si@C particles and accommodate the volume expansion during cycling. The Co/N co-doping further facilitates the transportation of Li ions. As expected, the Si@C/CNT electrode shows improved conductivity and long-term cyclic stability with a high-capacity retention ratio of 80.7% after 500 cycles at 0.5 A g⁻¹. In this study, the flexible and conductive connection design realized by the in situ synthesis of CNTs can provide some reference to the improvement of alloy-type anode materials and not just Si-based anode materials for LIBs.