铝、氟复合掺杂对锂离子电池正极材料锰酸锂电化学性能影响

Aluminum and fluorine co-doping for the electrochemical performance of spinel LiMn_2O_4 lithium ion battery anode

通过固相反应,以四氧化三锰(Mn_3O_4)中间体为锰源制备出锰酸锂(LiMn_2O_4)和氟、铝共掺杂的锰酸锂(LiMn_(1.9)Al_(0.1)O_(3.9)F_(0.1))锂离子电池正极材料。以XRD、SEM、充放电测试和循环伏安(CV)测试对其结构、形貌以及电化学性能进行了研究。结果表明,适量的铝(Al)、氟(F)掺杂未改变LiMn_2O_4的尖晶石结构。在0.2C倍率下,样品LiMn_2O_4和LiMn_(1.9)Al_(0.1)O_(3.9)F_(0.1)的首次放电比容量分别为120.1mAh/g和123.0mAh/g,循环100次后,容量保持率分别为75.27%和87.40%,样品LiMn_(1.9)Al_(0.1)O_(3.9)F_(0.1)表现出更好的循环稳定性。在5C倍率下,LiMn_(1.9)Al_(0.1)O_(3.9)F_(0.1)的放电比容量为90.0mAh/g,而LiMn_2O_4的放电比容量仅为71.4mAh/g。结果表明,铝(Al)、氟(F)共同掺杂在抑制Jahn-Teller畸变的基础上,进一步提高了LiMn_2O_4的放电比容量,明显改善了材料的循环稳定性和倍率性能。

The lithium-ion battery anode material spinel LiMn2O4 and LiMn（1.9）Al（0.1）O（3.9）F（0.1） samples were synthesized by sol-gel reaction route,the effects of aluminum and fluorine co-doping on the structure,morphology and electrochemical performance of material were studied by XRD,SEM and CV,respectively.The results indicated that appropriate amount doping of Al and F doesn＇t change the spinel structure of LiMn2O4.Moreover,the samples of LiMn2O4 and LiMn（1.9）Al（0.1）O（3.9）F（0.1） had an initial discharge capacity of 120.1mAh/g and 123.0mAh/g at 0.2C,and 75.27% and 87.40% of the original capacity were reserved after 100 cycles,respectively.LiMn（1.9）Al（0.1）O（3.9）F（0.1） had better cycling performance.LiMn（1.9）Al（0.1）O（3.9）F（0.1） had the discharge capacity of 90.0mAh/g at 5C,higher than the 71.4mAh/g of LiMn2O4.It concluded that Al and F co-doping can improve the initial discharge capacity of LiMn（1.9）Al（0.1）O（3.9）F（0.1）,and enhanced the electrochemical performance.