复合掺杂改性的尖晶石LiMn_(1.98)Cr_(0.02)O_(4-y)Cl_y的研究

Studies on the Co-doping Modified Spinel LiMn_(1.98)Cr_(0.02)O_(4-y)Cl_y

采用改进的高温固相法合成了阴阳离子复合掺杂改性的锂离子电池尖晶石结构正极材料LiMn1.98Cr0.02O4-yC ly(y=0,0.01,0.02,0.03,0.04,0.05,0.10).采用X射线衍射手段对材料的晶体结构进行了表征.从材料的晶体结构、充放电容量、循环性能和倍率放电特性等方面分析了复合掺杂在稳定晶体结构和改善材料电化学性能方面的作用.实验结果表明,由于复合掺杂的综合作用,改性后的材料既保持了高的初始容量,又具有优良的循环性能,倍率放电性能也得到了有效的改善.其中LiMn1.98Cr0.02O3.96Cl0.04的综合性能最优,初始放电比容量达到127 mA.h/g以上,循环50次后仍有110 mA.h/g的放电比容量.

The co-doping modified spinel LiMn（1.98）Cr（0.02）O（4-y）Cly（y =0, 0.01, 0.02, 0.03, 0.04, 0.05, 0. 10） as the cathode for lithium ion battery were synthesized with high-temperature solid-state reaction methed. X-ray diffraction were used to characterize the crystal structure of the produced materials. The effects of co-doping modification in stabilizing the crystal frame and improving the electrochemical properties were comparatively investigated in terms of crystal structure, charge and discharge capacity, cycle performance and rate performance. The investigation comes to the conclusions that the co-doping modified cathode materials held the high enough initial capacity and represented an excellent cycle performance as well. In addition, the rate performance was also improved obviously. Among the co-doped materials, the most outstanding general performance belongs to LiMn（1.98）Cr（0.02）O（3.96）Cl（0.04） which showed an initial specific discharge capacity of more than 127 mA·h/g and kept 110 mA· h/g after 50 cycles.