富锂材料zMnO_x·(1-z)Li[Ni_(0.2)Li_(0.2)Mn_(0.6)]O_2的性能优化

Rich Lithium Materials zMnO_x·(1-z)Li[Ni_(0.2)Li_(0.2)Mn_(0.6)]O_2 Performance Optimization

提出厚层材料改性的概念,对比常规包覆和厚层包覆对材料性能改善的差异,通过对材料的结构、形貌及电化学性能的表征,深入分析厚层包覆Mn Ox使富锂二元材料电化学性能得到明显提高的原因。厚层包覆材料0.1Mn Ox·0.9Li[Ni_(0.2)Li_(0.2)Mn_(0.6)]O_2的XRD图谱和HRTEM图像观察到包覆层厚度达20 nm,且包覆层中存在少量的尖晶石结构。电化学测试结果得出,厚层包覆材料具有较高的首次库伦效率(90.2%),较高的可逆容量(30周循环容量保持在265m Ahg^(-1)),同时循环其低倍率性能相比于本体材料和常规包覆材料同样有很大的提升(1C下放电比容量238m Ahg^(-1),2C下222m Ahg^(-1))。

We broadened the concept of surface modification method and chose 0.05MnOx·0.95Li [ Ni0.2Li0.2Mn0.6] 02 and O.lMnOx·0.9Li [ Ni0.2Li0.2Mn0.6 ]O2 materials for detailed discussion in conventional coating and thick coating respectively. The morphology observations and XRD results show that the thickness of coating layer of the modified sample O.lMnOx·0.9Li [ Ni0.2Li0.2Mn0.6 ] 02 is about 20 nm and there is a tiny amount of spinel structure in the coating layer. The electrochemical performance results indicate that the thick coated materials O.lMnOx·0.9Li [ Ni0.2Li0.2Mn0.6 ]02 exhibit higher reversible capacity （ 265 mAh g^-1 after 30 cycles ）,higher initial coulombic efficiency （ 90.2% ） and lower rate discharge capability （ above 238 mAhg^-1 at 1 C, 222 mAhg^-1 at 2 C ） than those of the pristine sample and conventional coated sample, respectively.