Shenzhen Key Laboratory of Power Battery Safety Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tinghua University, Shenzhen 518055, China;Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, China;Shenzhen Key Laboratory of Power Battery Safety Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tinghua University, Shenzhen 518055, China;Shenzhen Key Laboratory of Power Battery Safety Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tinghua University, Shenzhen 518055, China;School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;Shenzhen Key Laboratory of Power Battery Safety Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tinghua University, Shenzhen 518055, China;Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, China;School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Abstract:
Porous Si can be synthesized from diverse silica (SiO2) via magnesiothermic reduction technology and widely employed as potential anode material in lithium ion batteries. However, concerns regarding the influence of residual silicon oxide (SiOx) component on resulted Si anode after reduction are still lacked. In this work, we intentionally fabricate a cauliflower-like silicon/silicon oxide (CF-Si/SiOx) particles from highly porous SiO2 spheres through insufficient magnesiothermic reduction, where residual SiOx component and internal space play an important role in preventing the structural deformation of secondary bulk and restraining the expansion of Si phase. Moreover, the hierarchically structured CF-Si/SiOx exhibits uniformly-dispersed channels, which can improve ion transport and accommodate large volume expansion, simultaneously. As a result, the CF-Si/SiOx-700 anode shows excellent electrochemical performance with a specific capacity of ~1,400 mA·h·g?1 and a capacity retention of 98% after 100 cycles at the current of 0.2 A·g?1.
