Turning rice husks to a valuable boron and nitrogen co-doped porous C/SiOx composite for high performance lithium-ion battery anodes

For the exploitation of green biomass waste, boron (B) and nitrogen (N) co-doped porous C/SiO x composites (BN@C/SiO x ) have been successfully synthesized applying rice husks (RHs) as both C and Si sources and NH 4 HB 4 O 7 as the porogen reagent and heteroatom source via a one-step calcination route. The volume fluctuation of SiO x can be effectively relieved and the electronic conductivity can be substantially enhanced with the homogeneous distribution of SiO x particles in the B, N co-doped porous C matrix. Specially, B, N co-doping effectively reduces the transmission barrier of Li + in C skeleton of C/SiO x . The unique porous architecture, large specific surface area and B, N co-doping endow BN@C/SiO x with the large reversible capacity, exceptional rate property and superior cycling stability. As lithium-ion batteries (LIBs) anodes, the optimized BN@C/SiO x exhibits the cycling capacity of 1165 mAh/g at 100 mA/g and ameliorated initial coulombic efficiency (CE) of 74.3%. Even at 1.0 A/g, a stable cycling capacity of 650 mAh/g still can be obtained after 1200 cycles. This research offers a potential, relatively effective, cheap and environmental design of heteroatom doped biomass materials with enhanced Li + storage performance. • SiO x particles uniformly disperse in B, N co-doped C skeleton in BN@C/SiO x composite. • B, N Co-doping effectively reduces Li + transmission barrier in C skeleton of C/SiO x . • The presence of B and N increase specific capacity and initial CE of C/SiO x electrode. • Hierarchical porous B, N co-doped C skeleton enhances stability of SEI film on C/SiO x .