Core-shell structure of porous silicon with nitrogen-doped carbon layer for lithium-ion batteries

In this work, we develop a one-step carbonization method for constructing a core-shell structure of porous silicon with nitrogen-doped carbon layer for lithium-ion batteries. As a result, the porous silicon is evenly coated with a layer of nitrogen-doped carbon. Benefit from the internally stable structure of porous silicon and the support of external carbon layer, the whole electrode shows excellent structural stability. Excitingly, nitrogen-doped carbon layer is successfully obtained, and three different carbon-nitrogen species are identified, which significantly increases the electronic conductivity of composite electrode. Most importantly, the as prepared core-shell structure p-Si/NC composites deliver a stable cycling performance with 720 mA h g(-1) after 200 cycles at the current density of 200 mA g(-1) and a favorable rate capacity of 550 mA h g(-1) at the current density of 2 A g(-1). Additionally, the preparation process in this paper is more economical and feasible to achieve large-scale production.