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.