Li_2MnSiO_4/C复合正极材料的合成及电化学性能

Synthesis and Electrochemical Performance of Li_2MnSiO_4/C Composite Cathode Materials

采用溶胶-凝胶法合成了Li2MnSiO4/C复合正极材料,并用TG-DTA,XRD和电化学性能测试对材料进行了表征。前驱体的TG-DTA曲线表明,合成Li2MnSiO4时烧结温度应高于500℃。XRD测试表明Li2MnSiO4具有正交结构,对应Pmn21空间群。将Li2MnSiO4/C组装成扣式电池进行电化学测试的结果表明,600℃烧结10h所得样品性能最好,首次放电比容量达到124.2mAh·g-1,为理论比容量的74.5%;循环30次后放电比容量为71.5mAh·g-1。

A kind of cathode materials of Li2MnSiO4/C composites for Li-ion batteries has been prepared by sol-gel method. The samples are characterized by thermo gravimetric-differential thermal analysis （TG-DTA）, X-ray diffraction （XRD）, and electrochemical performance measurement. The TG-DTA curves of precursor show that the Li2MnSiO4 can be obtained at temperatures above 500 ℃. The XRD patterns indicate that the Li2MnSiO4 crystallized in an orthorhombic structure with a space group of Pmn21. The electrochemical test demonstrates that the Li2MnSiO4/C composite synthesized at 600 ℃ for 10 h shows the best electrochemical performance with an initial discharge capacity of 1242 mAh·g^-1, 74.5% of the theoretical capacity, and retains a discharge capacity of 71.5 mAh·g^-1 after 30 cycles.