Phosphoric acid induced homogeneous crosslinked phosphorus doped porous Si nanoparticles with superior lithium storage performance

The high volume expansion and low electrical conductivity issues severely limit practical application of Si-based materials for Li ion batteries (LIBs). Here we prepare the homogeneous crosslinked phosphorus (P) doped porous Si nanoparticles (P doped pSi) via magnesiothermic reduction of P contained nanosize SiO₂ (P-SiO₂). Phosphoric acid (H₃PO₄) acts as a bifunctional additive to reduce particle size of SiO₂ and achieve P doping of porous Si. The employment of this modified nanosize SiO₂ as precursor effectively alleviates the agglomeration of Si grains. Besides, the P doping characteristic is quite effective to promote the charge transfer performance of Si anode. Finally, P doped pSi anode displays superior cycle capacity and rate capability in half cells with 1761 mAh g⁻¹ at 0.5 A g⁻¹ after 80 cycles and 700 mAh g⁻¹ at 5 A g⁻¹ even after 400 cycles. Furthermore, the electrochemical performance of P doped pSi//LiFePO₄ full cell is also evaluated. All the results indicate that P doped pSi is an excellent competitor to replace traditional graphite anode for LIBs.