Micron SiOx encapsulated into amorphous B, N Co-doped carbon nanotube network for high-capacity and long-durable Li-ion half/full batteries

Abstract

Micron silicon suboxide (m-SiOx) with low-cost and advantageous capacity has been proposed as a prospective candidate for lithium-ion battery anodes, yet huge volumetric fluctuation and poor inherent conductivity should be addressed urgently. Herein, encapsulation of m-SiOx particles into amorphous B, N co-doped carbon nanotube network (SSBCN) via metal cation-assisted carbonization is shown. Rational preparation process enables in-situ synthesis of 3D porous carbon nanotubes network around m-SiOx, guaranteeing slight volume variation during cycling, effective electrical contact, fast electron and Li-ion transfer and speedy electrolyte penetration. In-situ Raman spectra confirm the additional utilization rate of m-SiOx. Heteroatomic active sites (Sn, N, B) further enhance lithium storage capacity. As anodes in half batteries, the SSBCN exhibits ultrahigh reversible capacities of 2072.8 mAh/g at 0.1 A/g, excellent rate performance of 501.8 mAh/g at 10 A/g and prominent long-term cycle stability of 400 and 1000 cycles at 1 and 5 A/g, respectively. Moreover, SSBCN//LiFePO4 (LFP) full batteries also display remarkable cycle durability with a 92.72% capacity retention after 600 cycles at 1C. This work outperforms most of the recently reported SiOx-based anodes and renders a new opportunity of m-SiOx in high-performance LIBs.