【摘要】 采用溶胶凝胶方法合成Li[Li0.2Mn0.54Ni0.13Co0.13]O2富锂正极材料,通过化学沉积技术在Li[Li0.2Mn0.54Ni0.13Co0.13]O2颗粒表面沉积La F3颗粒.利用X-射线衍射(XRD)、扫描电子显微镜(SEM)、充放电测试、循环伏安及交流阻抗测试系统研究了La F3包覆对材料电化学性能的影响.合成的材料具有α-Na Fe O2层状结构且La F3颗粒均匀包覆在颗粒表面,表面修饰La F3后的样品表现出更高的比容量和更好的倍率性能,电化学性能测试表明La F3表面修饰层有助于缓解电解液中HF对活性材料的腐蚀,降低电荷跃迁电阻(Rct),增强锂离子的扩散能力.更多还原

【Abstract】 Li[Li0. 2Mn0. 54Ni0. 13Co0. 13]O2cathode materials were successfully prepared by solgel method and subsequently surface-modified with La F3 particle via chemical deposition technique.The effects of La F3-coating on the electrochemical performances were investigated systematically by XRD,SEM,charge-discharge test,cyclic voltammetry(CV),and AC impedance,respectively.The obtained results show that the as-prepared powder has α-Na Fe O2 layered structure and the La F3 particles are uniformly deposited on the Li[Li0. 2Mn0. 54Ni0. 13Co0. 13]O2surface. In comparison with Li[Li0. 2Mn0. 54Ni0. 13Co0. 13]O2,Li[Li0. 2Mn0. 54Ni0. 13Co0. 13]O2/ La F3 demonstrates higherdischarge capacity and better rate performances. Analysis from electrochemical measurements reveals that La F3 coating layer can hinder interaction between active materials and HF in the electrolyte,reduce the charge transfer resistance(Rct) and enhance the Li-ion diffusion in solid. surface. In comparison with Li[Li0. 2Mn0. 54Ni0. 13Co0. 13]O2,Li[Li0. 2Mn0. 54Ni0. 13Co0. 13]O2/ La F3 demonstrates higherdischarge capacity and better rate performances. Analysis from electrochemical measurements reveals that La F3 coating layer can hinder interaction between active materials and HF in the electrolyte,reduce the charge transfer resistance(Rct) and enhance the Li-ion diffusion in solid.更多还原