Scalable synthesis of Si/SiO2@C composite from micro-silica particles for high performance lithium battery anodes

Abstract

Silicon/silica (Si/SiO2) composite is prepared directly from irregular micro-silica via mechanical milling followed by modified magnesiothermic reduction process. After that, phenolic resin is introduced as carbon source to fabricate the silicon/silica@carbon (Si/SiO2@C) composite. The structure of the composite is revealed by x-ray diffraction (XRD). SEM and TEM observations reveal that the micro-silica particles are broken into submicron scale and part of the silica particles are reduced to silicon by Mg reduction. When evaluated as an anode material for Li-ion batteries, the electrochemical performance of the composite is good. At 50mAg−1, the Si/SiO2@C (50wt.% C) sample exhibits a high initial charge capacity of 685.8mAhg−1. After 100cycles, it retains reversible capacity of 482mAhg−1. The composite also shows superior rate performance. At 500mAg−1, it can deliver high reversible capacity of 462.3mAhg−1. Considering the facile preparation and low-cost of raw material, the prepared Si/SiO2@C composite holds promise in practical Li-ion batteries.