SiO_(x)@g-C_(3)N_(4)复合材料的制备及储锂性能

Preparation and lithium storage performance of SiO_(x)@g-C_(3)N_(4)composite

硅材料因理论比容量远高于石墨,受到广泛关注,但阻碍发展的关键是硅的体积膨胀。通过热缩聚和还原原位合成SiO_(x)@类石墨相氮化碳(g-C_(3)N_(4))复合材料,并研究储锂性能。XRD、SEM和X射线光电子谱(XPS)分析结果表明:SiO_(x)均匀分散在g-C_(3)N_(4)片构成的空腔中,形成SiO_(x)@g-C_(3)N_(4)复合材料。电化学性能测试结果表明:SiO_(x)@g-C_(3)N_(4)复合材料以0.1 A/g的电流在0.01~3.00 V循环,首次充电比容量为1410 mAh/g,库仑效率为76.4%;以1.0 A/g的电流循环700次,可逆比容量保持在488 mAh/g,库仑效率为99.7%。g-C_(3)N_(4)片层结构既缓解了硅材料的体积膨胀与粉化,又提高了导电性,因此SiO_(x)@g-C_(3)N_(4)复合材料表现出良好的电化学性能。

Silicon material had attracted extensive attention because its theoretical specific capacity was much higher than that of graphite,but the key to hinder its development was the volume expansion of silicon.SiO_(x)@graphitic carbon nitride(g-C_(3)N_(4))composite was in-situ synthesized by thermal condensation polymerization and reduction,the lithium storage performance was studied.The XRD,SEM,X-ray photoelectron spectroscopy(XPS)analyzing results showed that SiO_(x) was evenly dispersed in the cavity formed by g-C_(3)N_(4)sheets to form SiO_(x)@g-C_(3)N_(4)composite.The electrochemical performance test results showed that the initial specific charge capacity and Coulombic efficiency of SiO_(x)@g-C_(3)N_(4)composite were 1410 mAh/g and 76.4%,respectively,when cycled at the current of 0.1 A/g in 0.01-3.00 V.It delivered reversible specific capacity of 488 mAh/g and Coulombic efficiency of 99.7%after 700 cycles at 1.0 A/g.The grid structure of g-C_(3)N_(4)not only inhibited the defects of silicon volume expansion and pulverization,but also improved conductivity,so SiO_(x)@g-C_(3)N_(4)composite exhibited good electrochemical performance.