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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。
The SiO 2 @ carbon-graphene (SiO_2 @ C-G) hybrid with excellent electrochemical performance was prepared by self-assembly of silica sol, sucrose and graphene oxide by ultrasonic assisted hydrothermal method and subsequent heat treatment. The results show that the mass ratio of SiO_2 to sucrose is an important factor affecting the electrochemical performance of SiO_2 @ C-G hybrids. 15-SiO_2 @ C-G hybrids (mass ratio of SiO_2 to sucrose 0.15) showed better reversible lithium storage performance. The current density was 100 m A · g -1, the first discharge capacity was 906 mA · g -1, and after 216 cycles, the discharge capacity of the electrode material could be maintained at 542 mA · g -1 ~ (-1). Excellent cycling stability and reversible capacity are attributed to the good electrical conductivity of the hybrid, the smaller size of the SiO 2 particles and the synergic effect among the three. The proposed method is expected to provide a simple and environmentally friendly preparation strategy for metal oxide based electrode materials with poor conductivity.