采用前驱体混合烧结法制备的LiCoO2的电化学性能

摘要

采用前驱体混合烧结法制备60%LiCoO 2-40%LiNi 0.5 Mn 0.3 Co 0.2 O 2(摩尔分数)复合材料，采用X射线衍射(XRD)和场发射扫描电镜(FESEM)对试样的显微组织和形貌进行表征，采用差热分析(TG-DSC)和过充试验测试该材料的安全性能。结果表明：与物理混合材料相比，复合材料具有很好的层状结构。混合烧结法通过前驱体的烧结使两种材料晶粒产生了融合，而产生晶粒融合的材料既保持了LiCoO 2的高体积能量密度(容量为156 mA∙h/g、压实密度为4.0 g/cm3)，还改善了材料的导电能力和安全性能。使用该材料制成的1.6 A∙h聚合物全电池，不但可以通过1C/12 V过充测试，而且具有优良的循环性能。该复合材料在常温和45℃下循环500次，容量保持率仍在85%以上。%60%LiCoO 2-40%LiNi 0.5 Mn 0.3 Co 0.2 O 2 (mole fraction) compound material was synthesized by precursor mixed sintering method. The microstructure and morphology of the compound material were characterized by X-ray diffraction (XRD) and field emitted scanning electronic microscopy (FESEM). The safety performance was analyzed by TG-DSC and abuse test. The results show that, compared with physical mixing material, the compound material has a better bonded crystalline and mixing effect, resulting in improved conductivity and structural stability. The material has high capacity (156 mA∙h/g), high pressing density (4.0 g/cm3) and improved safety. 1.6 A∙h polymer cells with compound material not only show excellent cycle life at room temperature and elevated temperature, the capacity retention is more than 85%after 500 cycle, but also exhibit good overcharge performance.