Novel design and synthesis of carbon-coated porous silicon particles as high-performance lithium-ion battery anodes

Porous silicon-based materials are considered promising next generation lithium-ion battery anode materials. Here, we report the rational design of multiscale recombined porous Si/C composites via a controllable and simple Ag-assisted chemical etching process with subsequent heat treatment of porous Si and chitosan composites (porous Si/CTS) which prepared by self-assembly process. Chitosan is a green, nontoxic and biodegradable carbon source. The three-dimensional porous (3D porous) structure accommodates the huge volume changes during lithiation and delithiation, which helps form more stable solid electrolyte interface (SEI) film and significantly improves the electrochemical stability. The multiplicity conductive network is constructed by Ag nanoparticles and carbon layer, which keep conductive contact and maintain structure stability. The Li-ion battery anode based on porous Si/C exhibits a reversible high capacity of 782.1 mAh/g at 0.5 C after 200 cycles with excellent Coulombic efficiency. This work opens a promising approach for production of high-performance micro-sized silicon-based anode materials in Li-ion battery.