Interfacial Issues and Modification of Solid Electrolyte Interphase for Li Metal Anode in Liquid and Solid Electrolytes

摘要

The high energy density required for the next generation of lithium batterieswill likely be enabled by a shift toward lithium metal anode from theconventional intercalation-based anode such as graphite. However, severalcritical challenges for Li metal originate from its highly reactive nature andthe hostless reaction of deposition and stripping impede the practical use ofLi metal as an anode. The role of the solid electrolyte interphase (SEI) is veryimportant for the Li metal anode where the SEI must protect the dynamicallychanging surface of the Li metal. Since the SEI-generating reaction mechanismsfor the two different electrolyte systems, liquid and solid, are considerablydifferent, the SEI layers formed between the Li metal and the electrolytesin the two electrolyte systems have substantially different properties, causingdifferent interfacial issues. Inhibition of the interfacial problems requires differentstrategies to reinforce the SEI layer for each of the electrolyte systems.However, the differences in the two electrolyte systems have not been clearlycompared in the prior literature. In this report, the interfacial issues for thetwo different electrolyte systems are compared and different strategies for SEImodification are provided to overcome the issues.