双碳源制备磷酸钒锂及其电化学性能研究

Preparation and Electrochemical Performance of Lithium Vanadium Phosphate with Double Carbon Sources

摘要:

以葡萄糖为主碳源，抗坏血酸(AA)为辅助碳源，采用固相法合成了倍率性能优良的碳包覆磷酸钒锂(LVP/C-AA)复合正极材料。通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、拉曼光谱(Raman)、恒电流充放电测试、循环伏安(CV)和交流阻抗(EIS)测试表征了材料的物相、形貌、结构和电化学性能。结果表明，添加少量的抗坏血酸为辅助碳源，对Li3V2(PO4)3晶体结构没有明显的影响，但能明显提高Li3V2(PO4)的高倍率性能。LVP/C-AA在5 C时的首次放电比容量可达162.4 mAh g-1，100次循环后容量保持率高达80.4%。

Abstract:

Using glucose as main carbon source and ascorbic acid (AA) as accessory carbon source, carbon coated lithium vanadium phosphate (LVP/C-AA) with high-rate performance was successfully synthesized by a solid-state reaction. The phases, morphologies, structures and electrochemical performance of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), charging and discharging measurements, cyclic voltammogram (CV) testing and electrochemical impedance spectra (EIS). The results show that using ascorbic acid as accessory carbon source has no effect on the crystal structure of Li3V2(PO4)3, but enhances the high-rate performance. The LVP/C-AA electrode delivers an initial capacity as high as 162.4 mAh g-1 at 5 C, and shows an excellent capacity retention ration of 80.4% even after 100 cycles.