In-situ construction of solid polymer electrolyte with regulated Li-polymer interaction for high-performance solid-state Li metal batteries

The practical application of lithium metal batteries (LMB) is severely hindered owing to the fatal side reactions and dendritic growth of Li, while the development of solid-state LMB by using solid polymer electrolytes (SPE) can address these issues. Employing in-situ polymerization method is a feasible strategy for the large-scale production of SPE. However, its ionic conductivity and high voltage stability is still unsatisfactory. Herein, we developed a new SPE based on the in-situ polymerization of 2-vinyl-1,3-dioxolane (VDOL). The double bond addition reaction of VDOL induced by free radical polymerization endows the formation of enriched adjacent carbonyl functional group in polymer chain, which significantly enlarges its high-voltage tolerance and facilitates the formation of densified sites for favored Li + interaction and promoted ion conduction. In addition, the strengthened chemical interaction between Li + and C-O groups in SPE not only enhances the lithium salt dissociation, but also effectively regulates Li deposition and immobilizes anions. Attributed to its regulated Li-polymer interaction, the designed Ah-level pouch type LMB paired with sulfur cathode demonstrates a high energy density of 314.8 Wh kg −1 and decent cyclic stability, which provides a new strategy of developing high performance SPE and related electrochemical devices . Solid polymer electrolyte with regulated Li-polymer interaction was prepared by in-situ polymerization strategy, which is able to achieve inhibited shuttle effect of polysulfides and regulated Li deposition toward high performance solid-state lithium metal battery. The asassembled Ah-level pouch-type lithium metal battery with sulfur cathode can deliver a high energy density of 314.8 Wh kg −1 , offering a promising route toward the practical application. • The V-PDOL polymer electrolyte with a wide electrochemical stability window (4.7 V), high ionic conductivity (1.87 ×10 −4 S cm −1 at 25 ℃), and rapid ion migration ability (0.59) was prepared by free radical polymerization process through molecular structure regulation. • The abundant C O and C-O-C functional groups in the V-PDOL segment can serve as Li + coordination sites, promoting lithium salt dissociation and establishing continuous Li + transport channels, thereby improving its ionic conductivity . • The carbonyl polar group (C O) can serve as active site for the chemical adsorption of polysulfides, effectively suppressing shuttle effects, thereby improving cycling stability and rate performance when used in solid-state lithium metal battery. • Experimental tests demonstrated that the formation of stable organic/inorganic composite SEI can effectively suppress side reactions as well as improve interfacial compatibility.