Sol-gel法制备的LiTi2-xMnx(PO4)3@C复合纳米材料及其储锂性能  

Sol-gel Synthesis of LiTi2-xMnx(PO4)3@C Composite Nanoparticles as a Superior Cathode Material for Lithium-Ion Batteries

作　　者：夏宗梅 胡芳东 胡语清 赵萌 张雪梅 姜晓蕾 XIA Zong-Mei;HU Fang-Dong;HU Yu-Qing;ZHAO Meng;ZHANG Xue-Mei;JIANG Xiao-Lei(School of Chemistry and Chemical Engineering,Linyi University,Linyi,Shandong 276005,China)

机构地区：[1]临沂大学化学化工学院,临沂276005

出　　处：《无机化学学报》2020年第4期620-626,共7页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.21701079,21801109);山东省自然科学基金(No.ZR2017BB016,ZR2018BB019);大学生创新创业训练计划项目(No.201910452010);山东省本科教改项目(Z2018S006)资助。

摘　　要：通过简单的溶胶-凝胶方法成功合成一系列Nasicon型LiTi2-xMnx(PO4)3@C(x=0.02,0.05,0.08和0.1)。掺入异价元素锰增大了LiTi2(PO4)3的晶格参数,从而扩大Li^+的传输通道,并降低了电化学阻抗。同时材料的表面包覆均匀的导电碳层以提高电子的传输速率。所有复合材料通过粉末X射线衍射仪及透射电子显微镜进行表征。LiTi1.92Mn0.08(PO4)3@C作为锂离子电池正极材料表现出最佳的电化学性能。在0.1C倍率下,电池循环150次后放电容量高达145 mAh·g^-1,增大至5C倍率下首次充放电达到132mAh·g^-1。优异的电化学性能可归因于掺杂提高了锂离子扩散系数及包覆碳材料降低了传荷阻抗。A Nasicon-type LiTi2-xMnx(PO4)3@C(x=0.02,0.05,0.08 and 0.1)has been successfully synthesized by a simple sol-gel method.The precipitates were annealed at 700℃for 10 h in Ar.The metallic ion doping could increase their lattice parameters,along with the large available tunnels for Li+diffusion,and then decrease the electrochemical resistance.The carbon layer plays an important role in improving the electronic conductivity.These composites were characterized via powder X-ray diffractometry with Cu Kαline as a radiation(λ=0.15418 nm).The morphologies were observed by a transmission electron microscopy.The molar ratio of nMn:nTi was obtained from ICP-AES analysis.Among the samples,LiTi1.92Mn0.08(PO4)3@C exhibited the best electrochemical performance as a cathode material for lithium ion batteries,with a discharge capacity of 145 mAh·g^-1 after 150 cycles at 0.1 C.It even delivered a discharge capacity of 132 mAh·g^-1 in the first cycle at 5 C.This superior electrochemical property could be ascribed to its enhanced lithium-diffusion induced by doping and improved electronic conductivity induced by carbon coating.

关 键 词：掺杂 碳包覆 溶胶-凝胶法 正极材料 电化学性能 

分 类 号：O646[理学—物理化学]