Mo_(2)C/PE隔膜对锂硫电池性能的影响  

Effect of Mo_(2)C/PE Separator on the Performance of Lithium Sulfur Batteries

作　　者：王前[1,2] 魏祎 贾洪声 WANG Qian;WEI Yi;JIA Hongsheng(Tonghua Normal University,Tonghua 134002,China;Key Laboratory of Functional Materials Physics and Chemistry,Ministry of Education,Jilin Normal University,Siping 136000,China)

机构地区：[1]通化师范学院,通化134002 [2]吉林师范大学功能材料物理与化学教育部重点实验室,四平136000

出　　处：《高等学校化学学报》2023年第11期138-145,共8页Chemical Journal of Chinese Universities

基　　金：吉林省自然科学基金(批准号:20200201236JC);吉林省发展和改革委员会产业技术研究与开发项目(批准号:2022C040-6)资助。

摘　　要：为了提升对锂金属负极的保护作用,抑制多硫化物的穿梭效应,选择成本低且地球丰富度高的钼基材料合成球壳结构的碳化钼(Mo_(2)C),并制备了碳化钼修饰的聚乙烯隔膜(Mo_(2)C/PE),分析了Mo_(2)C/PE隔膜对锂硫电池性能的影响.结果表明, Mo_(2)C良好的亲锂性可以诱导Li+均匀沉积,抑制锂枝晶生长. Mo_(2)C/PE隔膜具有较大的比表面积和孔隙率,碳化钼可以促进多硫化物在其附近的碳球内沉积成硫化锂,增加的形核位点和沉积空间对充放电过程中引起的体积变化有一定的改善效果.制备的Li-Li对称电池在较高的电流密度下,与不使用PE隔膜的电池相比,使用Mo_(2)C/PE隔膜电池的极化电压起伏更小,可以稳定循环.装有Mo_(2)C/PE隔膜的锂硫电池在0.2C的倍率下,放电比容量为1235.3 mA·h/g,经过500次循环后,放电容量可以维持在652.4 mA·h/g.In order to enhance the protective effect of lithium metal negative electrodes and suppress the shuttle effect of polysulfides,the molybdenum based materials with low-cost and high Earth abundance were selected to synthesize molybdenum carbide(Mo_(2)C)with spherical shell structure,and the molybdenum carbide modified polyethylene separators(Mo_(2)C/PE)was prepared.The influence of Mo_(2)C/PE separators on the performance of lithium sulfur batteries was analyzed.The results indicate that the good lithium affinity of Mo_(2)C can induce uniform deposition of Li+and inhibit the growth of lithium dendrites.The Mo_(2)C/PE separator has a large specific surface area and porosity,which has a certain improvement effect on the volume changes caused by the charging and discharging process.Compared to the battery without PE separator,Li-Li symmetric battery using Mo_(2)C/PE separator has smaller polarization voltage fluctuations and can stably cycle at higher current density.Lithium sulfur batteries equipped with Mo_(2)C/PE separators have a specific discharge capacity of 1235.3 mA·h/g at a rate of 0.2C,and after 500 cycles,the discharge capacity can be maintained at 652.4 mA·h/g.

关 键 词：碳化钼 碳化钼/聚乙烯隔膜 锂硫电池 锂负极 电化学性能 

分 类 号：O646[理学—物理化学]