Intermolecular chemistry in high-entropy solid polymer electrolytes enabling room temperature solid-state lithium metal batteries†

Abstract

Solid polymer electrolytes with excellent processability have attracted tremendous attention in advanced solid-state lithium metal batteries (SSLMBs), while their application remains a tough challenge due to the trade-off between high ionic conductivity and good mechanical strength. Here, via in situ polymerization, the unique Li⁺ solvation structures as well as abundant hydrogen bonds are inserted into a high-entropy supramolecular zwitterion solid polymer electrolyte (HESZ-SPE), significantly facilitating Li⁺ transport and improving mechanical properties at room temperature (RT). The in situ polymerized HESZ-SPE exhibits high electrochemical stability and excellent interfacial stability, and thus promotes the uniform Li⁺ plating/stripping revealed by COMSOL simulation. Remarkably, the HESZ-SPE achieves the balance in excellent mechanical strength, high ionic conductivity (4.60 × 10⁻³ S cm⁻¹), and an appreciable Li⁺ transference number (0.86) for RT SSLMBs. Consequently, the HESZ-SPE provides excellent cycling stability, high coulombic efficiency and favorable rate capability at RT in SSLMBs, holding great promise in enabling high-performance electrochemical energy storage.