自蔓延法制备富锂型正极材料及其储锂性能研究

Preparation and Characterization of Lithium-rich Layereds Oxides by Self-propagating Method and Lithium Storage Performance

基于高比容量、高电压区间和长循环等优异性能,富锂型正极材料在锂离子电池领域的应用受到广泛关注.本文通过自蔓延燃烧法制备富锂正极材料xLi_(2)MnO_(3)·(1-x)Li Ni_(1/3)Co_(1/3)Mn_(1/3)O_(2)(x=0.4、0.5、0.6),并探讨了x值、烧结温度对于材料的形貌和电化学性能的影响.利用X射线衍射(X-Ray Diffraction,XRD)、扫描电镜(Scanning Electron Microscope,SEM)、比表面及粒径分析等方法对材料的物相结构和微观形貌进行了表征,并探讨了材料对其电化学性能的影响.样品均为纯相的层状结构,所得材料的粒径尺寸约为200 nm.自蔓延燃烧法制备的富锂正极材料具有较好的电化学性能,0.6Li_(2)MnO_(3)·0.4LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)的首圈放电比容量为255 mAh/g.在2.3~4.8 V、0.1 C的充放电条件下,经过100圈充放电后,其容量保持率达84%.

Due to the excellent properties of high specific capacity,high voltage range and long cycle,the application of Li-rich cathode materials in the field of lithium-ion batteries has attracted wide attention.In this paper,the lithium rich cathode material xLi_(2)MnO_(3)·(1-x)LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(x=0.4,0.5,0.6)was prepared by selfpropagating combustion method.The effects of x value and sintering temperature on the morphology and electrochemical properties of the material were investigated.The phase structure and micro-structure of the materials were characterized through the application of X-ray diffraction(XRD),scanning electron microscopy(SEM),specific surface and particle size analysis.The influence of the materials on their electro-chemical properties was discussed.The samples are all pure phase layered structures,and the resulting material particle size is about 200 nm.The lithium-rich cathode material prepared by self-propagating combustion method has good electro-chemical performance,and the specific discharge capacity of 0.6Li_(2)MnO_(3)·0.4LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)is 255 mAh/g.Under the charge and discharge conditions of 2.3~4.8 V and 0.1 C,the capacity retention rate reaches 84%after 100 cycles.