锂离子电池正极材料尖晶石型LiMn_2O_4的制备及其掺杂改性

Preparation and Modification of Spinel LiMn_2O_4 Cathode Material for Li-ion Battery

采用固相合成法制备了锂离子电池用尖晶石型LiMn2O4正极材料,并通过同时加入Cr3+和F-对材料进行了体相掺杂改性.用扫描电子显微镜和X射线衍射研究了材料的表面形貌和晶体结构,用充放电循环实验对制备的锂离子电池性能进行了测试.结果表明:未掺杂的LiMn2O4正极材料首次放电容量为115.3 mAh?g-1,循环25次后容量降为96 mAh?g-1;掺杂Cr3+和F-的材料同样具有尖晶石型结构,随掺杂量增加,首次放电容量略有降低,但循环性能有较明显改善,充放电效率提高,其中掺杂量为0.10的样品首次放电容量为111.5 mAh?g-1,循环25次后容量保持率达91.8%.

Spinel LiMn2O4 cathode material for Li-ion battery was prepared by a solid-state reaction, and the material was modified by doping the Cr^3＋ and F at the same time. Its morphologies and structure were characterized by scanning electron micrograph and X-ray diffraction, and its electrochemical properties were studied by charge-discharge test. The results show that the 1^st and 25^th discharging capacity of LiMn2O4 is 115.3 mAh,g^-1 and 96 mAh.g^-1 respectively. When doping with Cr^3＋ and F, the cathode material also has a spinel structure. With the doping level increasing, the initial discharging capacity of material reduces, but its cycling performance and charge-discharge efficiency are greatly improved. When the doping level is 0.1, the sample displays an initial discharging capacity of 111.5mAh.g^-1, and its capacity retention after 25 cycles is 91.8%.