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

Abstract 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.