Customized polymer electrolytes for high-energy-density lithium batteries 

Solid-state batteries with lithium-rich manganese layered oxide (LRMO) cathodes, anode-free architecture, and polymer electrolytes deliver high energy density and enhanced safety. However, unstable cathode morphology and irreversible redox reactions at the electrolyte-cathode interface trigger severe interfacial degradation and poor cycling stability. Recently, Zhang’s team developed a fluoropolyether-based polymer electrolyte (PTF-PE-SPE), a copolymer synthesized via in situ polymerization of poly(ethylene glycol) methyl ether acrylate and fluorohydrocarbon monomers. Its anion-rich solvation environment drives the in-situ formation of fluorine-rich interphases at both electrodes and markedly improves the redox reversibility of LRMO. This quasi-solid polymer electrolyte with 30 wt.% trimethyl phosphate enables the LRMO cathode to achieve 604 Wh kg^-1 and 1,027 Wh L^-1 energy densities in pouch batteries. Despite this progress, practical deployment still requires low-fluorine electrolytes, uniform in situ polymerization in large batteries, mechanical robustness, and long-term stability with Li metal and high-voltage LRMO cathodes.