Boosting lithium rocking-chair engineering from the villus cavity and Ni catalytic center of a silicon–carbon anode for high-performance lithium-ion batteries

Abstract

Generally, the dynamic silicon nanoparticles (Si NPs) cores and static carbon shells of silicon–carbon anode materials mismatch all through the lithiation and de-lithiation of high-capacity Li-ion batteries (LIBs). Herein, we used nickel nanoparticles (Ni NPs) as a catalyst to induce the growth of “villus cavity” carbon nanotubes (CNTs) inside N-doped hollow carbon nanofibers (NHCF), which was firmly attached to active silicon nanoparticles (Si NPs), building an adaptive conductive and mechanical carbon network (Si@Ni-CNTs@NHCF). The high conductivity of the crustaceous NHCF of Si@Ni-CNTs@NHCF facilitated the carrier transfer. Moreover, the compact villus cavity formed by Ni-CNTs could buffer the volume fluctuations of Si NPs and maintain a conductive connection with the expanding/contracting Si NPs during the charge/discharge process. More importantly, the Ni catalytic activity of Ni-CNTs contributed to the balanced behavior of lithiation and de-lithiation for the improvement of structural compatibility and the long-cycle stability of the electrode. Notably, Si@Ni-CNTs@NHCF, with the current density of 1 A g⁻¹, had a high reversible capacity of 1072 mA h g⁻¹ after 1000 extremely long stable cycles. This work deepens our understanding of the structural modification of Si/C anodes by constructing a compatibly conductive, mechanical and catalytic material to achieve stable lithiation and de-lithiation cycling processes.