Ti掺杂对正极材料LiNi1/3Co1/3Mn1/3O2结构和电化学性能的影响

为研究离子掺杂对锂离子正极材料LiNi1/3Co1/3Mn1/3O2的影响,采用氢氧化物共沉淀法制备了Ti4+掺杂改性的锂离子正极材料LiNi1/3-1/40Co1/3Mn1/3Ti1/40O2、LiNi1/3-Co1/3-1/40Mn1/3Ti1/40O2和LiNi1/3Co1/3Mn1/3-1/40Ti1/40O2,并运用X射线衍射仪和扫描电子显微镜对Ti掺杂改性后正极材料的晶型和微观结构进行表征,通过高精度电池性能检测系统对正极材料的电化学性能进行检测.结果表明:Ti分别取代Ni、Co和Mn对三元复合正极材料进行掺杂改性后,改性材料都保持典型的α-NaFeO2层状结构,且晶型良好;LiNi1/3-Co1/3Mn1/3-1/40Ti1/40O2轮廓最分明,且形貌均一;3种改性材料的电化学性能均有一定程度的提高,其中LiNi1/3Co1/3Mn1/3-1/40Ti1/40O2提高最为明显,在0.1 C、1.0 C和2.0 C倍率下其首次放电比容量分别为145.35、140.79和125.60 mA.h/g,1.0 C倍率下循环30次后的容量保持率为88.06%.

Effects of Ti Doping on Structure and Electrochemical Performance of Cathode Material LiNi1/3CO1/3Mn1/3O2

In order to reveal the effects of ion doping on the structure and electrochemical performance of modified cathode material LiNi1/3Co1/3Mn1/3O2,three kinds of Ti-doped cathode materials for lithium ion battery,namely LiNi1/3-1/40Co1/3Mn1/3Ti1/40O2,LiNi1/3Co1/3-1/40Mn1/3Ti1/40O2 and LiNi1/3Co1/3Mn1/3-1/40Ti1/40O2,were synthesized via the coprecipitation of hydroxides.Then,the crystal forms and microstructures of the products were respectively characterized by means of XRD and SEM,and the electrochemical performances of the products were tested by using a high-precision battery-testing system.The results show that all the modified cathode materials with their Ni,Co and Mn components being partly substituted by Ti keep a typical α-NaFeO2 layered structure with perfect crystalline patterns,that LiNi1/3Co1/3Mn1/3-1/40Ti1/40O2 is of the clearest profile and even morphology,that the electrochemical performances of the three kinds of modified materials all improve after the Ti doping,especially LiNi1/3-Co1/3Mn1/3-1/40Ti1/40O2,and that,for LiNi1/3Co1/3Mn1/3-1/40Ti1/40O2 at the rates of 0.1 C,1.0 C and 2.0 C,the first specific discharge capacity respectively reaches 145.35,140.79 and 125.60 mA·h/g,and the capacity retention after 30 charge and discharge cycles at 1.0 C is up to 88.06%.