Chem. J. Chinese Universities ›› 2022, Vol. 43 ›› Issue (8): 20220166.doi: 10.7503/cjcu20220166

• Physical Chemistry • Previous Articles     Next Articles

Lithium Polystyrene Sulfonate Based Interfacial Protective Layer for Lithium Metal Anodes

LI Wei, LUO Piao, HUANG Lianzhan, CUI Zhiming()   

  1. Key Laboratory of Fuel Cell Technology of Guangdong Province,School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510641,China
  • Received:2022-03-17 Online:2022-08-10 Published:2022-05-26
  • Contact: CUI Zhiming E-mail:zmcui@scut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22072048)

Abstract:

Due to the ultrahigh theoretical specific capacity(3860 mA·h/g) and lowest negative electrochemical potential[?3.04 V(vs. SHE)], lithium metal has long been considered as an ideal anode for next-generation high- energy-density lithium batteries. However, several critical issues such as volume expansion, lithium dendrite, and side reaction have restricted its practical application. Here, lithium polystyrene sulfonic(PSSLi) was evenly coated on the surface of commercial lithium metal foil to form the PSSLi@Li composite electrode. Fourier transform infrared spectroscopy(FTIR), electrochemical impedance(EIS), battery performance test and finite-element-based solver simulation were used to analyze the physical and electrochemical properties of this composite anode. The results indicated the PSSLi layer can effectively avoid the side reaction between electrolyte and Li metal, restricting the formation of "dead Li". In addition, PSSLi with the neatly arranged sulfonic groups can homogenize the Li ions flux and distribution on the electrode surface, which ensures the uniform plating/stripping of Li metal. The electrochemical test showed that the coulombic efficiency of the PSSLi@Cu composite electrode can remain above 99.5% after 350 cycles. And the symmetrical cell assembled with PSSLi@Li composite electrodes presents an excellent cycling life over 1200 h under the current density of 1 mA/cm2 and area capacity of 1 mA·h/cm2. Moreover, the LiFePO4(LFP) coupled full cell can maintain at 115 mA·h/g under the rate of 1C after 500 cycles and realize an ideal capacity retention(81%). The full cell also exhibits an excellent rate performance of 105 mA·h/g at the rate of 8C.

Key words: Lithium metal anode, Lithium metal interface layer, Polystyrene sulfonate lithium, Fast ions transfer, Lithium dendrites

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