钛掺杂磷酸铁锂的合成及其充放电性能研究  

Synthesis and charge/discharge performances of titanium doped lithium iron phosphate

作　　者：吴彭森 王洋 葛佳佳 李紫金 李珍珍 邱冠周[1] WU Pengsen;WANG Yang;GE Jiajia;LI Zijin;LI Zhenzhen;QIU Guanzhou(School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China;Henan Baili New Energy Materials Co.,Ltd.,Jiaozuo 454000,Henan,China)

机构地区：[1]中南大学资源加工与生物工程学院,长沙410083 [2]河南佰利新能源材料有限公司,河南焦作454000

出　　处：《有色金属科学与工程》2025年第1期35-42,共8页Nonferrous Metals Science and Engineering

基　　金：河南省“十四五”重大项目资助(豫重点[2022]5号)。

摘　　要：元素掺杂是提高磷酸铁锂(LiFePO_(4))正极材料充放电性能的主要途径之一。以TiO_(2)为钛源,采用高温固相还原法合成了Ti掺杂的LiFePO_(4),通过XRD、XPS、SEM和BET等技术表征了钛掺杂LiFePO_(4)的结构组成、微观形貌和理化性能,进而对组成-结构与其充放电性能之间的影响关系进行了研究。结果表明:钛掺杂LiFePO_(4)在0.1 C和1 C倍率下的首次放电比容量最高分别达到161.9 mAh/g和150.8 mAh/g,比未掺杂钛的LiFePO_(4)提高4.72%和7.48%,且在1 C倍率下循环150周后容量保持率高达98.54%。这主要归因于Ti4+取代Fe^(2+)进入LiFePO_(4)晶格,稳固晶体结构的同时会抑制晶粒的二次生长,导致Li+脱/嵌路径减小,迁移效率加快,进而提高了LiFePO_(4)的放电比容量、倍率以及循环性能。Element doping is one of the main ways to improve the charge/discharge performances of lithium iron phosphate(LiFePO_(4))cathode materials.In this paper,modified LiFePO_(4)was synthesized by a high-temperature solid-state reduction method using TiO_(2)as a titanium source.The structural composition,micro-morphology,and physicochemical properties of titanium-doped LiFePO_(4)were characterized by XRD,XPS,SEM,and BET,and further,the relationship between composition-structure and charge/discharge performances was carefully studied.The results indicate that the first discharge-specific capacity of titanium doped LiFePO_(4)respectively reaches the maximum of 161.9 and 150.8 mAh/g at 0.1 C and 1 C rate,which is 4.72% and 7.48% higher than LiFePO_(4)without titanium doping,and the capacity retention rate achieves as high as 98.54% after 150 cycles at 1 C rate.This is mainly attributed to the substitution of Fe^(2+)by Ti4+into LiFePO_(4)lattice,which stabilizes the crystal structure and inhibits the secondary growth of crystalline grains,leading to a decrease in Li+extraction/insertion paths and an increase in migration efficiency,thereby improving the discharge specific capacity,rate,and cycle performances of LiFePO_(4).

关 键 词：钛掺杂 磷酸铁锂 充放电性能 

分 类 号：TM911.14[电气工程—电力电子与电力传动] TF111.52[冶金工程—冶金物理化学]