Acta Phys. -Chim. Sin. ›› 2021, Vol. 37 ›› Issue (2): 2008092.doi: 10.3866/PKU.WHXB202008092

Special Issue: Lithium Metal Anodes

• REVIEW • Previous Articles     Next Articles

Progress in Functional Solid Electrolyte Interphases for Boosting Li Metal Anode

Huaming Qian1,2,3, Xifei Li1,2,3,*()   

  1. 1 Institute of Advanced Electrochemical Energy, School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048, China
    2 Shaanxi International Joint Research Center of Surface Technology for Energy Storage Materials, Xi'an 710048, China
    3 Xi'an Key Laboratory for Advanced Energy Devices, Xi'an 710048, China
  • Received:2020-08-31 Published:2020-10-20
  • Contact: Xifei Li
  • About author:Xifei Li, Email: Tel.: +86-29-82312516
  • Supported by:
    the National Key Research and Development Program of China(2018YFB0105900)


The ever-increasing demand for high-energy Li-ion batteries has acted as a powerful stimulus for the development of Li metal as an anode material. Li metal has long been regarded as a "Holy Grail" in Li-ion batteries due to its high discharge capacity (3860 mAh·g-1) and low electric potential (-3.04 V). However, the formation of unstable solid electrolyte interphases (SEIs) and Li dendrites, as well as the resultant safety issues initiated by catastrophic dendrite growth, have greatly impeded further application. High ion conductivity, surface electron insulation, and favorable mechanical strength are essential properties for an ideal SEI film, which can allow for uniform Li deposition, providing a fast transfer path for Li ions and suppressing Li dendrite growth. Therefore, designing a functional SEI layer is an effective strategy to solve the problems encountered with Li metal anodes. So far, a variety of inorganic, organic, and inorganic/organic hybird SEI layers have been designed and fabricated. Inorganic SEIs are characterized by mechanical strength and ion conductivity; organic SEIs are flexible and have electron insulation properties. Inorganic/organic composite SEIs show favorable ion conductivity derived from the inorganic components, electron insulation properties originating from the organic components, and mechanical strength benefiting from the reinforcing effect between the inorganic and organic components. Oxides, metal sulfides, lithium nitride (Li3N) and its derivates, lithium halide (LiX, X = F, Cl), two-dimensional (2D) layered structure materials, lithium phosphate and "Janus" composite are the representative examples of inorganic SEIs. The design principle of various SEI layers is based on the inhibition of Li dendrite formation and growth. Therefore, it is a prerequisite to better understand the relevant intrinsic mechanisms. Despite past investigations, further studies are still required to fully elucidate the related mechanisms by providing more broadly accepted evidence combined with theoretical calculations and offer reliable guidance for the design of multifunctional SEI layers, boosting the performance of Li metal anodes. In this review, on the basis of the mechanisms underlying Li dendrite formation and growth, strategies for constructing various functional SEI films, highlights in structure and property of the films, and their effects on the performance of Li metal anodes are summarized. Moreover, some challenges encountered with the practical applications of Li metal anodes and the future direction for the development of Li metal anodes are addressed. This review can reveal possible strategies for the commercialization of high-energy, safe and stable Li-ion batteries.

Key words: Li metal anode, Li dendrite growth, Functional SEI film, Uniform Li deposition, High-energy battery