Highly stable SiOx/multiwall carbon nanotube/N-doped carbon composite as anodes for lithium-ion batteries

Fabricating high-capacity electrode materials with long cycle life is essential to developing high-power energy storage and conversion systems. SiOx is a very attractive anode material for lithium-ion batteries, but both low electronic conductivity and volume effect severely hamper its practical application. In this work, multiwall carbon nanotube (MWCNT) and N-doped carbon are combined to improve the electrochemical properties of SiOx. The synthesized composite (labeled as SiOx/MWCNT/N-doped C) has a network structure, in which MWCNT serves as a highly conductive and porous scaffold facilitating electron and ion transport, while N-doped C improves electric contact between SiOx/MWCNT particles and prevents the physical and electrochemical agglomeration of SiOx. The electrochemical measurement shows that the SiOx/MWCNT/N-doped C exhibits excellent cyclic stability and rate capability. At a current density of 100 mA g−1, a stable discharge capacity of about 620 mAh g−1 is achieved and the capacity can be preserved up to 450 cycles. The enhanced conductivity and stable electrode structure should be responsible for the excellent electrochemical performance.