Nitrogen-doped carbon caging silicon nanoparticles for high performance lithium-ion battery anodes

Abstract

Abstract Silicon is considered a valuable candidate for the anode material of lithium-ion batteries (LIBs) based on its high theoretical specific capacity and abundant resources in nature. Unfortunately, rapid capacity decay associated with volume expansion during cycling hinders the use of silicon in electrode materials for LIBs. Herein, we report nitrogen-doped carbon caging silicon nanoparticles (SiNP@NC cage) via simply coating and acid etching methods. The nitrogen-doped carbon shell can separate the silicon nanoparticles from the electrolyte, and the space between silicon nanoparticles and nitrogen-doped carbon cage offers adequate space for volume expansion of the silicon nanoparticles during the repeated cycling process. Besides, the amorphous carbon shell doped by nitrogen possesses more active sites on the surface. These properties are greatly conducive to the improvement of the electrochemical performance of silicon nanoparticles for Li-ion storage. The prepared SiNP@NC cage-2 manifests excellent electrochemical properties (1185.1 mAh g-1 after 100 cycles at the current density of 100\xa0mA\xa0g-1) when being evaluated as the anode material in LIBs.