采用离子交换法制备Co, Cr及Al掺杂LiMnO_2,通过X射线衍射、扫描电子显微镜和恒电流充放电等技术检测和分析合成产物的物相、形貌及电化学性能.研究表明掺杂后LiMnO_2仍然保持原来的结构,但晶粒形貌发生了改变,晶格常数总体变小.与未掺杂的LiMnO_2相比,Co、Cr及Al掺杂LiMnO_2具有更高的放电容量和更好的循环性能.随着掺杂量的增加,Co、Cr及Al掺杂LiMnO_2的放电容量逐步下降,但循环性能不断改善.在掺杂的LiMnO_2中,LiMn_(0.95)Cr_(0.05)O_2的放电容量最高,达到198.1mAh/g,而LiMn_(0.85)Al_(0.15)O_2的放电容量最小,LiMn_(0.90)Cr_(0.10)O_2循环性能最好,而Co掺杂的循环性能最差.
Cathode materials of Co, Cr and Al doped LiMnO_2 for lithium ion battery were prepared by ion exchange. Phase identification, surface morphology and electrochemical properties were studied by X-ray diffraction, scanning electron microscopy and galvanostatic charge-discharge experiments. The results show that the crystal parameter of doped LiMnO_2 is generally smaller than the undoped LiMnO_2. The surface morphology of the doped LiMnO_2 is different from LiMnO_2, while both structures are the same. All the doped LiMnO_2 offers higher discharge capacity and better cycling performance than LiMnO_2. The discharge capacity of the doped LiMnO_2 decreases, yet the cycling performance improves with the increase of doping concentration. For these doped LiMnO_2, LiMn_(0.95)Cr_(0.05)O_2 offers the highest discharge capacity of 198.1mAh/g and LiMn_(0.85)Al_(0.15)O_2 offers the lowest. The cycling performance of LiMn_(0.90)Cr_(0.10)O_2 is the best, while cobalt doped LiMnO_2 is the worst.
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