Multi‐Functional Membrane for Air‐Proof and High Temperature‐Stable Li Metal Batteries

Abstract Lithium metal is considered as the most potential anode for next generational high energy density lithium‐ion battery. But due to high activity, the whole manufacturing process of LMA must be protected by inert gas and placed in dry environment, which will increase the significant production cost. The security risk is also increased once unexpected overheating happens. Therefore, prior to the practical application of LMA, these critical issues should be solved. A flame retardant, triphenyl phosphate (TPP), is introduced in this paper. When used as a protective layer on the surface of LMA, it can improve air tolerance of LMA even in a RH 70 % environment. In addition, PVDF‐HFP/TPP complex separator can be constructed via blade casting process, which plays an efficient role in increasing heat stability and flame retardancy. And more meaningfully, the composite separator is expected to form a coating layer by hot‐rolling with LMA, enabling LMA remain stable while in regular production environment. Such a strategy has the function of cutting costs and high temperature protection.