摘要
为解决锂金属作为负极时锂金属/电解液界面的不稳定性和锂金属表面可能出现的锂枝晶生长问题,利用聚乙烯亚胺(PEI)与聚丙烯酸(PAA)的静电吸引作用包覆碳纳米管(CNT),通过真空抽滤的方式制备了PEI与PAA包覆CNT(CNT@PP)膜,对其微观形貌和分子结构进行表征,并将CNT@PP膜作为锂金属负极的保护层组装为电池,对电池的循环稳定性能、倍率性能和循环性能进行测试。结果表明:PEI和PAA均匀附着在碳纳米管上,并形成纳米级孔道结构;PEI与PAA具有强静电作用;在1.0 mA/cm^(2)的电流密度下,Li‖Li对称电池能稳定循环250 h,表明CNT@PP膜有利于锂的均匀沉积和界面稳定;在全电池恒流充放电中,CNT@PP膜能明显提高全电池的倍率性能,2.0 C下比容量达91 mAh/g,而无保护电池的比容量仅为22 mAh/g;在0.5 C长循环测试中,CNT@PP膜保护的电池可稳定循环200圈,并有75.21%的容量保持率。该研究表明,CNT@PP膜可以有效地保护锂金属负极,是改善锂金属电池的可行策略。
To solve the instability of the lithium/electrolyte interface and the possible growth of lithium dendrites on the surface of lithium metal when lithium metal was used as an anode, based on the electrostatic attraction of polyethyleneimine(PEI) and polyacrylic acid(PAA), carbon nanotubes were coated by PEI and PAA and then a PEI-and PAA-coated CNT(CNT@PP) film was prepared by vacuum filtration, and its microstructure and molecular structure were characterized. Batteries were assembled by using CNT@PP film as a protective layer of lithium metal anode, and the cycle stability, rate property and cycle property of the batteries were tested. The results showed that PEI and PAA were uniformly attached to the carbon nanotubes, nanoscale channels were formed and PEI had a strong electrostatic interaction with PAA. The Li‖Li symmetric cells can be stably cycled for 250 h at a high current density of 1.0 mA/cm^(2), which confirmed that the CNT@PP film was beneficial to the uniform deposition of lithium ions and the stabilization of surface of lithium metal. In constant current charge/discharge test of full battery, CNT@PP film can greatly improve the rate property of the full battery. Particularly, the specific capacity can reach 91 mAh/g at a high rate of 2.0 C. However, a full battery without protective layer only delivered a specific capacity of 22 mAh/g. What′s more, a full battery with CNT@PP film can be stably cycled for 200 cycles in the long-cycle test at 0.5 C, with a capacity retention rate of 75.21%. The research results in this paper show the CNT@PP film can effectively protect lithium metal anode and present a feasible strategy to improve lithium metal batteries.
作者
蔡志鹏
刘爱萍
叶方敏
CAI Zhipeng;LIU Aiping;YE Fangmin(School of Science,Zhejiang Sci-Tech University,Hangzhou 310018,China)
出处
《浙江理工大学学报（自然科学版）》
2023年第1期17-23,共7页
Journal of Zhejiang Sci-Tech University(Natural Sciences)
基金
浙江省杰出青年科学基金项目(LR19E020004)
浙江理工大学科研启动项目(18062299-Y)。
关键词
锂金属电池
界面
聚合物复合膜
高倍率
静电作用
lithium metal battery
interface
polymer composite films
high rate
electrostatic interaction
