3D Porous Silicon/N-Doped Carbon Composite Derived from Bamboo Charcoal as High-Performance Anode Material for Lithium-Ion Batteries

The exploitation of renewable biomass resources toward green, high-value-added functional nanomaterials is promising. Bamboo is a "natural Si reservoir" that contains a considerable amount of silica. Available bamboo charcoal is the carbonated bamboo material with attractive features. Herein, 3D porous silicon is extracted from bamboo charcoal by simple calcination and magnesiothermic reduction. For an improvement in the electrochemical stability, the porous Si is further coated with a layer of N-doped amorphous carbon by carbonizing the polyacrylonitrile precursor. The obtained silicon/nitrogen-doped carbon composite possesses a 3D porous structure and exhibits significantly improved cycling performance along with high rate capabilities. The optimized Si/N-doped carbon composite delivers a reversible capacity of 603 mA h g–1 after 120 cycles at 200 mA g–1 and a high capacity of 360 mA h g–1 at 1.6 A g–1. This demonstrates that the N-doped amorphous carbon layer can effectively accommodate the volume change of the 3D porous silicon and reduce the charge transfer resistance so as to improve the cycling durability of the Si/carbon composite. The overall preparation process of the Si/N-doped carbon composite is economic, environmentally friendly, and scalable. This work provides a sustainable solution from bamboo charcoal resource to hierarchically porous silicon/carbon composites for cost-efficient lithium-ion battery anode materials.