A sustainable approach from rice husks to P,N-dual doping porous C/SiOx composites for high-performance lithium-ion battery anodes

Abstract

• SiO x particles uniformly dispersed in P,N co-doped C skeleton in PN@C/SiO x composite. • P,N co-doped C skeleton availably enhance electronic conductivity of C/SiO x composite. • The presence of P and N increase specific capacity and initial CE of C/SiO x electrode. • Hierarchical porous P,N co-doped C skeleton enhance stability of SEI film on C/SiO x. For the development of sustainable crop-based energy materials, phosphorus and nitrogen binary doped porous C/SiO x composites (PN@C/SiO x ) have been fabricated using rice husks as the Si and C source and (NH 4 ) 3 PO 4 as the P and N source through a facile and environmentally friendly approach. The obtained PN@C/SiO x composites possess a hierarchical porous structure and SiO x particles are uniformly distributed in the P,N-doped C skeleton. The porous P,N-doped C skeleton not only facilitates the ion transport and penetration of electrolyte, but also alleviates the volume expansion and agglomeration of SiO x particles. The P and N co-doping can generate additional defective sites on the C matrix surface, which enhances electronic conductivity and energy storage performance. Due to the above advantages, the optimized PN@C/SiO x composite as anode of lithium-ion batteries (LIBs) presents an excellent reversible specific capacity of 1078 mAh/g at 0.1 A/g and improved initial coulombic efficiency (CE) of 73.6%. Even at 1.0 A/g, a steady specific capacity of 622 mAh/g still could be achieved after 1000 cycles. It is believed that this strategy has great potential in large-scale production of new energy materials for future practical applications.