铬掺杂锰酸锂的正极材料离子热法制备及其性能

Ionothermal synthesis and properties of Cr-doped LiMn_2O_4 cathode materials

以乙醇胺醋酸盐作为反应介质,采用硫酸铬、一水氢氧化锂和新制备二氧化锰为原料,在常压低温下采用离子热法和后续高温处理,制备了正极材料Li Mn2O4及其掺杂改性物Li Cr0.1Mn1.9O4。分别对材料的形貌和电化学性能进行XRD、SEM和充放电测试。SEM测试结果表明:Li Mn2O4和Li Cr0.1Mn1.9O4均为棒状结构,集中呈现为长宽分别为1.2μm、200 nm。充放电测试表明:金属铬的掺杂能有效提高材料的循环性能,在0.1 C倍率下,材料Li Cr0.1Mn1.9O4首次放电比容量为123.6 m A·h/g,经历前10个循环的容量少量衰减后,其后的50次循环中容量基本不变。

The LiMn2O4 and its Cr-doped cathode material LiCr0.1Mn1.9O4 were synthesized by ionothermal method, using bis- （1-hydroxyethyl） ammonium acetate as the reaction mediums at an atmospheric pressure and a low temperature with Cr2 （SO4）3, LiOH· H2O ,and MnO2 as sources, and followed by heat treatment.The materials were characterized by X-ray diffraction,scanning electron microscopy,and electrochemical test,respectively.The SEM result indicated that the LiMn204 and LiCr0.1Mn1.9O4 materials had rodqike structure with the length of about 1.2 μm and the diameter of about 200 nm.The galvanostatic charge-discharge tests demonstrated that a small amount of Cr could effectively improve the electrochemical performance of the materials, and LiCr0.1Mn1.9O4 material had an initial discharge specific capacity of 123.6 mA. h/g at 0.1 C. Furthermore ,the discharge capacities of LiCr0.1Mn1.9O4 sample faded slowly before 10 cycles and then remained unchanged in following 50 cycles.