摘要
为了降低电池极化现象,提升锂氧电池的电化学性能,采用液相扩散法制备锶掺杂的ZIF-8催化剂材料。以硝酸锶和乙酸锌为金属离子本体原料,以2-甲基咪唑为有机配体,以聚乙烯吡咯烷酮为结构导向剂,液相扩散获得锶掺杂的ZIF-8催化剂材料,并通过SEM和TEM测试考察材料的形貌,TGA测试验证材料的结构稳定性,同时借助电化学设备测试材料的电化学性能。实验结果表明:当硝酸锶和乙酸锌的摩尔比为2∶1时,得到的Sr-ZIF-8材料呈六边形片状的形貌;TGA测试表明该材料有较好的结构稳定特性;将材料制成电极应用到锂氧电池中,在100 mA/g的电流密度下,进行恒流充放电测试时,电池首圈可获得4048.5 mA·h/g的放电比容量,放电平台电压值为2.67 V,放电过程的过电势仅为0.29 V;在进行限容300 mA·h/g的条件下,同样的电流密度下可循环27圈,表现出了较好的循环稳定性能。
In order to reduce the phenomenon of battery polarization and improve the electrochemical performance of lithium-oxygen batteries,strontium-doped ZIF-8 catalyst materials were prepared by liquid-phase diffusion method with raw materials from strontium nitrate and zinc acetate as for metal ions,2-methylimidazole as an organic ligand,and polyvinylpyrrolidone as a structure directing agent.The morphology of the material was observed by SEM and TEM.The TGA test verified the structural stability of the material.At the same time,the electrochemical performance of the material was tested with the aid of electrochemical equipment.The experimental results show that when the molar ratio of strontium nitrate to zinc acetate is 2∶1,the obtained Sr-ZIF-8 material has a hexagonal flaky morphology;TGA test shows that the material has good structural stability.The electrode made of the material was applied into lithium-oxygen battery.When the constant current charge and discharge test is performed at a current density of 100 mA/g,the initial specific discharge capacity is 4048.5 mA·h/g,and the discharge platform is 2.67 V,the overpotential of discharge is only 0.29 V.Under the condition of limited capacity of 300 mA·h/g,it can run for 27 cycles under the same current density,showing good cycle stability performance.
作者
阮艳莉
张萌
顾祥顺
王天宇
RUAN Yan-li;ZHANG Meng;GU Xiang-shun;WANG Tian-yu(School of Chemistry and Chemical Engineering,Tiangong University,Tianjin 300387,China)
出处
《天津工业大学学报》
CAS
北大核心
2020年第6期61-67,共7页
Journal of Tiangong University
基金
国家自然科学基金资助项目(21403153)。
关键词
锂氧电池
ZIF-8
掺杂
正极催化剂
液相扩散法
结构导向剂
Li-O2 batteries
ZIF-8
doping
cathode catalyst
liquid-phase diffusion method
structure directing agent
