LiFePO_4/C多层膜的制备及电化学性能研究  

Preparation and Electrochemical Properties of LiFePO_4/C Multilayer

作　　者：陈昶 曹凤红 邓迟[1] 徐要辉 刘春海 张伟 CHEN Chang;CAO Feng-hong;DENG Chi;XU Yao-hui;LIU Chun-hai;ZHANG Wei(School of Physics and Electronic Engineering,Leshan Normal University,Leshan 614000,China;School of Materials and Chemical Engineering,Chengdu University of Technology,Chengdu 610059,China;Analysis and Test Center,Sichuan University of Science and Engineering,Zigong 643000,China;Key Laboratory for Material Corrosion and Protection of Sichuan Province,Zigong 643000,China)

机构地区：[1]乐山师范学院物理与电子工程学院,四川乐山614000 [2]成都理工大学材料与化学化工学院,成都610059 [3]四川理工学院分析测试中心,四川自贡643000 [4]材料腐蚀与防护四川省重点实验室,四川自贡643000

出　　处：《表面技术》2019年第2期76-81,共6页Surface Technology

基　　金：国家自然科学基金资助项目(51201111);材料腐蚀与防护四川省重点实验室开放基金项目(2015CL04);乐山师范学院校级培育计划青年项目(z16005);乐山市科技局重点研究项目(18JZD098)~~

摘　　要：目的研究LiFePO_4/C多层膜在不同的调制周期下的电化学性能。方法采用多靶磁控溅射方法,在304不锈钢基底上,先沉积10 nm Ti薄膜作为阻挡层,然后交替沉积LiFePO_4薄膜和C薄膜,制备三组不同调制周期的[LiFePO4/C]n多层膜。通过扫描电子显微镜(SEM)及其附带的EDS能谱仪对退火前和经500℃退火2 h后的不同调制周期[LiFePO_4/C]n多层膜的截面形貌、成分进行表征,利用X射线衍射仪(XRD)对退火前和经500℃退火2 h后的LiFePO_4薄膜及不同调制周期[LiFePO4/C]n多层膜的结构进行表征,利用激光显微拉曼光谱仪(Raman)分析经500℃退火2 h后不同调制周期[LiFePO_4/C]n多层膜中的C结构,利用循环伏安和恒流充放电法对LiFePO_4薄膜和不同调制周期[LiFePO_4/C]n多层膜的电化学性能进行测试。结果调制周期为7.5次的[LiFePO4 (160 nm)/C(16 nm)]7.5多层膜中的碳石墨化程度高于调制周期为15次的[LiFePO4(80 nm)/C(8 nm)]15和调制周期为5次的[LiFePO_4 (240 nm)/C(24 nm)]5多层膜,且具有更好的充放电容量和倍率性能。在0.1 C放电倍率下,[LiFePO_4 (160 nm)/C(16 nm)]7.5多层膜的放电容量为151 mAh/g,在5 C高放电倍率下的放电容量为30 mAh/g。结论适当的调制周期下,LiFePO_4/C多层膜具有良好的电化学性能。The work aims to study the electrochemical properties of LiFePO4/C multilayer films in different modulation periods.10 nm Ti film was deposited on 304 stainless steel as the barrier layer by multi-target magnetron sputtering and then the LiFePO4/C films were deposited alternately to prepare three[LiFePO4/C]n multilayer films with different modulation periods.The cross-sectional morphology and composition of[LiFePO4/C]n multilayer films with different modulation periods before and after annealing at 500℃for 2 h were characterized by SEM and EDS.The structure of LiFePO4 film and[LiFePO4/C]n multilayer films with different modulation periods before and after annealing at 500℃for 2 h was characterized by XRD.The C structure of[LiFePO4/C]n multilayer films with different modulation periods after annealing at 500℃for 2 h was characterized by Raman.The electrochemical property of LiFePO4 film and[LiFePO4/C]n multilayer films with different modulation periods was evaluated by cyclic voltammetry and galvanostatic charge-discharge tests.The degree of graphitization in[LiFePO4(160 nm)/C(16 nm)]7.5(the modulation cycle of 7.5 times)multilayer was higher than that in[LiFePO4(80 nm)/C(8 nm)]15(the modulation cycle of 15 times)and[LiFePO4(240 nm)/C(24 nm)]5(the modulation cycle of 5 times)multilayers.The[LiFePO4(160 nm)/C(16 nm)]7.5 multilayer had better charge-discharge capacity and rate performance than the[LiFePO4(80 nm)/C(8 nm)]15 and[LiFePO4(240 nm)/C(24 nm)]5 multilayers.The specific capacity of[LiFePO4(160 nm)/C(16 nm)]7.5 was 151 mAh/g at 0.1 C,and the specific capacity was 30 mAh/g at 5 C.LiFePO4/C multilayer has good electrochemical properties under the appropriate modulation period.

关 键 词：多靶磁控溅射 304不锈钢 LiFePO4/C多层膜 调制周期 石墨化程度 电化学性能 

分 类 号：O646.54[理学—物理化学] TM911.1[理学—化学]