SiOx embedded in N-doped carbon nanoslices: A scalable synthesis of high-performance anode material for lithium-ion batteries

Abstract

SiOx is a promising anode material for lithium-ion batteries owing to its smaller volume expansion and longer lifespan than silicon. However, its development is severely hampered by the sluggish reaction kinetics and large volume changes. Herein, a facile and scalable synthesis of exfoliated N-doped carbon nanoslices supported SiOx (SiOx/NCS) is developed by a melamine assisted ball milling and annealing procedure. The principle of melamine in exfoliating graphite is demonstrated by contrast experiments and theoretical calculations. It is found NCS acts as matrix to enhance the reaction kinetics and accommodate the volume changes which contributes to the significant improvements of cycling performance and rate capability. The SiOx/NCS anode exhibits ultrastable cycling performance (∼900 mAh g−1 over 600 cycles at 1 A g−1) and superior rate capability (565 mAh g−1 at 5 A g−1). At a high mass loading of 3.3 mg cm−2, an ultrahigh areal capacity of 2.4 mAh cm−2 is obtained after 200 cycles. Moreover, the potential application of SiOx/NCS anode in LIBs is also confirmed by the good performance of SiOx/NCS//NCM111 full cells.