Boron-doped spherical hollow-porous silicon local lattice expansion toward a high-performance lithium-ion-battery anode

Abstract

Silicon (Si) attracts extensive attention as the advanced anode material for lithium (Li)-ion batteries (LIBs) because of its ultrahigh Li storage capacity and suitable voltage plateau. Hollow porous structure and dopant-induced lattice expansion can enhance the cycling stability and transporting kinetics of Li ions. However, it is still difficult to synthesize the Si anode possessing these structures simultaneously by a facile method. Herein, the lightly boron (B)-doped spherical hollow-porous Si (B-HPSi) anode material for LIBs is synthesized by a facile magnesiothermic reduction from B-doped silica. B-HPSi exhibits local lattice expansion located on boundaries of refined subgrains. B atoms in Si contribute to the increase of the conductivity and the expansion of lattices. On the basis of the first-principles calculations, the B dopants induce the conductivity increase and local lattice expansion. As a result, B-HPSi electrodes exhibit a high specific capacity of ∼1500 mAh g–1 at 0.84 A g–1 and maintains 93% after 150 cycles. The reversible capacities of ∼1250, ∼1000, and ∼800 mAh g–1 can be delivered at 2.1, 4.2, and 8.4 A g–1, respectively.