多孔LiFePO_4锂电池正极材料制备及电化学性能研究  

Preparation and its electrochemical characteristics research of multiporous lithium iron phosphate as a cathode material for lithium ion battery

作　　者：华丽[1,2,3] 赵迪[1] 戴伟[1] 戴月[1] 黄青[1] 段连生[1] 

机构地区：[1]湖北第二师范学院化学与生命科学学院,武汉430205 [2]华中科技大学材料科学与工程学院,武汉430074 [3]华中科技大学机械科学与工程学院,武汉430074

出　　处：《华中师范大学学报（自然科学版）》2014年第5期703-710,共8页Journal of Central China Normal University：Natural Sciences

基　　金：湖北省高等学校优秀中青年科技创新团队建设计划项目(T201225);<植物抗癌活性物质提纯与应用>湖北省重点实验室项目;湖北第二师范学院优秀科研教师团队建设计划项目(2012K203);湖北第二师范学院化学重点学科建设计划项目(2013XZXK05)

摘　　要：聚苯乙烯微球（PST）作模板成功地制备出了三维（3D）多孔LiFePO4锂电池正极材料,并与传统固相法制备的LiFePO4比较,分析形貌、性能差异.结果显示,固相法合成的LiFePO4近似呈球形,颗粒大小不均,平均粒径约80～220 nm.而模板法合成产物具有3D多孔结构,孔径较为均匀.BET测试显示,3D多孔LiFePO4比表面积较大,为11.239 8 m^2/g,单孔体积为0.034 cm3/g,而固相法合成产物比表面积为2.003 2 m^2/g,单孔体积为0.006 cm3/g.因此,3D多孔LiFePO4为锂电池中锂离子嵌入和脱出提供便利通道.电化学性能显示,两种方法在3.3～3.5 V电压区间有一个较好充电和放电平台,固相法最大充放电比容量为60～70 mAh·g^-1,而模板法合成的多孔材料其稳定性较好,充放电比容量基本稳定在170 mAh·g^-1左右.电化学阻抗谱（EIS）分析,多孔的LiFePO4材料其欧姆接触电阻（R1）、电化学反应的电荷转移电阻（R2）和半无限边界条件下的扩散阻抗（W1）较之固相法合成LiFePO4材料均小,3D多孔结构有利于减少因阻抗引起的电池容量的损耗,增强电池的稳定性,提高可逆比容量.Three-dimensional （3D） multiporous LiFePO4 as a cathode material for lithium ion battery was prepared triumphantly by employing macromolecular polystyrene （PST） microspheres as a template,its morphology and characteristics were analyzed and compared to that prepared by the conventional solid-phase method.It shows that products prepared by the solid phase method are sphere-like,not uniform,the size is about 80～220 nm.However,LiFePO4 attained by the templating method has a multiporous microstructure,porous size is uniform.BET analyses showed that it also has a larger specific surface area of 11.239 8 m^2/g and a single porous volume of 0.034 cm3/g for 3D multiporous LiFePO4,while the area is 2.003 2 m^2/g and a single porous volume is 0.006 cm3/g for the LiFePO4 prepared by the solid-phase method.Therefore,3D multiporous LiFePO4 can provide a handy chunnel for extraction and insertion of Li＋ ions for lithium battery.Electrochemical analysis shows that there are both a good charge and discharge platforms at 3.3～3.5 V for LiFePO4 by two methods.However,the biggest charge/discharge capacity of LiFePO4 acquired by solid phase method is fixed to be 60～ 70 mAh · g^-1,while it is 170 mAh · g^-1 by the template method.Electrochemical impedance spectrum （EIS） shows that there are a lower ohm contact resistance （R1）,electric charge transfer resistance （R2） in electrochemical reaction and diffuse wurburg impedance （W1） for LiFePO4 prepared by template method than that by solid phase method,also multiporous microstructure is benefit to prevent capacity attenuation which is caused by impedance,improve its stability and reversible capacity.

关 键 词：三维(3D)多孔 LIFEPO4正极材料 锂电池 电化学性能 

分 类 号：O614[理学—无机化学]