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在采用低温共沉淀-水热-煅烧法合成锂离子电池Fe-Ni-Mn体系正极材料Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的基础上,对合成的材料Li1.6(Fe0.2Ni0.2Mn0.6)O2.6进行V2O5的包覆改性研究,以提高材料Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的首次放电比容量和循环性能。用XRD、SEM、TEM、ICP光谱和恒流充放电测试研究包覆材料的结构和电化学性能。结果表明,V2O5包覆并没有改变材料的晶体结构,只存在于材料的表面,与未包覆的材料相比,V2O5包覆后的材料具有更好的首次放电容量和容量保持率。50周循环后,添加质量分数3%V2O5样品Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的放电比容量可以维持在200.3 mAh/g,大于未添加V2O5样品Li1.6(Fe0.2Ni0.2Mn0.6)O2.6的194.0 mAh/g。CV测试表明,包覆层的存在有效抑制了材料层状结构的转变及电极与电解液的负反应。
Based on the synthesis of Li1.6 (Fe0.2Ni0.2Mn0.6) O2.6 as Fe-Ni-Mn system cathode material for Li-ion battery by low temperature coprecipitation-hydrothermal-calcination method, the synthesized Li1.6 Fe0.2Ni0.2Mn0.6) O2.6 V2O5 coating modification study to improve the material Li1.6 (Fe0.2Ni0.2Mn0.6) O2.6 first discharge capacity and cycle performance. The structure and electrochemical properties of the coatings were investigated by XRD, SEM, TEM, ICP and constant current charge-discharge tests. The results show that the V2O5 coating does not change the crystal structure of the material and exists only on the surface of the material. Compared with the uncoated material, the V2O5 coated material has better initial discharge capacity and capacity retention. After 50 cycles, the specific discharge capacity of Li1.6 (Fe0.2Ni0.2Mn0.6) O2.6 with the mass fraction of 3% V2O5 can be maintained at 200.3 mAh / g, which is larger than that of Li1.6 (Fe0. 2Ni0.2Mn0.6) 194.0 mAh / g of O2.6. The CV test shows that the existence of the coating effectively inhibits the transformation of the layered structure of the material and the negative reaction between the electrode and the electrolyte.