尖晶石锰酸锂的柠檬酸辅助溶胶-凝胶法合成及电化学表征  

Synthesis and electrochemical characterizations of spinel LiMn_2O_4 by citric acid-assisted sol-gel method

作　　者：王超[1] 刘兴泉[1] 张峥[1] 向小春[1] 刘宏基[1] 

机构地区：[1]电子科技大学微电子与固体电子学院电子薄膜与集成器件国家重点实验室,四川成都610054

出　　处：《化工科技》2011年第6期1-6,共6页Science & Technology in Chemical Industry

基　　金：国家自然科学基金资助项目(21071026);电子科技大学杰出人才引进项目资助(08JC00303)

摘　　要：以醋酸锰、氢氧化锂为原料,以柠檬酸为络合剂,n(柠檬酸):n(锂)=1:1,采用柠檬酸辅助溶胶-凝胶法制备了富锂尖晶石Li1+xMn2O4(x=0,0.02,0.05,0.07),采用TG-DTA、XRD、SEM分别对前驱体和目标材料进行了表征,采用恒流充放电及循环伏安(CV)测试对材料进行了电化学性能表征,考察了不同n(Li):n(Mn)对材料性能的影响。结果表明,材料的最佳烧结温度为750℃,前驱体经750℃煅烧可获得晶体结构完整和形貌规整的尖晶石型锰酸锂,最佳n(Li):n(Mn)=1.05:2,在0.5C和3.4～4.35V电压条件下,Li1.05Mn2O4的初始放电容量达到124.5mAh/g,90次循环后放电容量保持率达到92.5%。显示了良好的综合电化学性能。The spinel Li1＋xMn2O4（x=0,0.02,0.05,0.07）cathode materials were prepared by a citric acid-assisted sol-gel method using LiOH and Mn（CH3COO）2 as raw materials and citric acid as the chelating agent,the molar ratio of citric acid to Li was 1∶1,and the precursors and resultant materials were characterized by TG-DTA,SEM and XRD,respectively.The electrochemical properties of the materials were investigated by galvanostatic charge and discharge and CV test.The influence of Li/Mn molar ratios on the electrochemical properties of Li1＋xMn2O4 cathode materials was examined.The results revealed that the optimal sintering temperature was 750 ℃,the well-defined pure cubic spinel phase can be obtained by calcining the precursor at 750 ℃.The optimal Li/Mn molar ratio was 1.05∶2,and the initial discharge capacity of Li1.05Mn2O4 was 124.5 mAh/g at 0.5C and 3.4~4.35V range,it remained 92.5% of the initial specific discharge capacity after 90 cycles.The Li1.05Mn2O4 displayed better electrochemical performance.

关 键 词：尖晶石锰酸锂 柠檬酸络合物 溶胶-凝胶法 锂离子电池 正极材料 

分 类 号：TQ137.12[化学工程—无机化工] TM912.9[电气工程—电力电子与电力传动]