锂电负极用SiO_2@碳-石墨烯杂化材料的制备（英文）

Synthesis of SiO_2 @carbon-graphene hybrids as anode materials of lithium-ion batteries

采用超声辅助的水热法及后续热处理法,将硅溶胶、蔗糖、氧化石墨烯自组装制备出具有优异电化学性能的SiO_2@碳-石墨烯(SiO_2@C-G)杂化物。结果表明:SiO_2与蔗糖的质量比是影响SiO_2@C-G杂化物电化学性能的重要因素。15-SiO_2@C-G杂化物(SiO_2与蔗糖的质量比为0.15),表现出较好的可逆储锂性能。电流密度为100 m A·g^(-1) ,首次放电比容量为906 m Ah·g^(-1) ,循环216次后,该电极材料的放电比容量可保持在542 m Ah·g^(-1) 。优异的循环稳定性及可逆容量归因于杂化物良好的导电性,SiO_2颗粒较小的尺寸及均匀分布三者之间的协同效应。该文提出的方法有望为导电性差的金属氧化物基电极材料提供一种简单环保的制备策略。

SiO2@ carbon-graphene （SiO2@ C-G） hybrids with excellent electrochemical performance were prepared by the self-assembly of colloidal silica, sucrose and graphene oxide followed by ultrasonic-assisted hydrothermal and heat treatments. The mass ratio of silica to sucrose is crucial to the electrochemical performance of the resulting hybrids. A hybrid with a mass ratio of silica to sucrose of 0.15 shows the best reversible lithium storage performance, delivering an initial discharge capacity of 906 mAh＊g-1 and a capacity of 542 mAh＊g-1 at the 216th cycle at a current density of 100 mA＊g-1. The excellent cycling ability and high reversible ca-pacity are attributed to a synergetic effect of the good conductivity of the SiO2 @ C-G hybrids, the small SiO2 particle size and the good dispersion of SiO2 nanoparticles in the hybrids. This methodology may provide a simple, scalable and eco-friendly strategy to prepare superior electrode materials from cheap and low electrical conductivity metal oxides.