Efficient Synthesis of N-Doped SiO_<i>x</i>/C Composite Based on the Defect-Enriched Graphite Flake for Lithium-Ion Battery

Abstract

The two-dimensional (2D) defect-enriched nanomaterials have aroused great interests, owing to its special electronic properties and the fast transport of lithium ions. Herein, we present a facile and mature method to cage SiOx nanoparticles into the defect-enriched graphite flake through ball-milling for 4 h (GF-4), assisted by solid diluent 4-aminophenol (4-AP). 4-AP prevents reaggregation of the graphite flakes and excessive formation of defect carbon during the milling process. Moreover, it further consolidates the layered sandwiching structure and introduces nitrogen element into the SiOx/C/GF-4 composite after carbonization. Thus, the N-SiOx/C/GF-4 composite not merely retains a 3D electronic and flexible framework to guarantee the excellent structural compatibility but optimizes simultaneously the transport and the high diffusion rate of lithium ions in the electrodes. It displays an excellent cycle performance of 525.2 mAh g–1 over 500 cycles (1 A g–1) and a superior rate performance of 334 mAh g–1 (5 A g–1). Furthermore, the full cell based on N-SiOx/C/GF-4 and commercial NCM622 cathode demonstrates a commendable gravimetric energy density of 413.2 Wh kg–1.