High-performance free-standing N-doped C/SiOx film anode materials for lithium ion batteries

Silicon-carbon composites are considered as the most promising anode materials for lithium ion batteries. Currently, most silicon-carbon composites were prepared by solid nano‑silicon particles as the silicon source, which suffers from high price and uneven dispersion. Here, we used tetraethyl orthosilicate as the liquid silicon source and polyvinylpyrrolidone as the carbon source. Both were homogeneously mixed in the liquid phase, and then processed through electrospinning, carbonization and nitrogen-doped processes to obtain free-standing nitrogen-doped carbon coated silicon monoxide (N-doped C/SiOx). When served as anode material, N-doped C/SiOx can possess a reversible capacity of 488 mAh g−1 at 0.5 C (0.6 A g−1) and 377 mAh g−1 at a high current density of 2 C (2.4 A g−1). In addition, copper foil is not used as a collector for free-standing electrode structure, and eliminates the coating process of traditional electrodes, which reduces production costs. It is proposed that a facile strategy to fabricate silicon-carbon composites with good electrochemical properties and cost-effective way for lithium ion batteries.