Cation-π Mediated Weak Solvation Chemistry Enables Dendrite-Suppressed Gel Polymer Electrolytes

Gel polymer electrolytes (GPEs), despite their flexibility, non-leakage, and processability as promising candidates of electrolytes for high-energy-density lithium batteries, persistently face the challenge of high desolvation energy caused by robust solvation interactions. Such high desolvation energy compromises interfacial kinetics, resulting in uneven lithium deposition and uncontrollable lithium dendrite growth. In this study, we reveal that the off-domain π-electron cloud of the aromatic ring in the side chains can introduce cation-π interactions to engineer weakly solvated structures, substantially reducing desolvation barriers. In addition, it is demonstrated that cation-π interactions competitively disrupt Li⁺-solvent coordination, attenuating binding forces between Li⁺ and solvent molecules to promote rapid interfacial kinetics, thereby suppressing the lithium dendrite growth and enhancing interfacial stability. As a result, the cation-π chemistry enables Li||Li symmetric cell to achieve stable lithium plating/stripping over 2000 h, whereas Li||LFP full cell retains 91.6% capacity after 900 cycles at 1 C. Remarkably, 1.0 Ah pouch cell preserves 94.6% capacity after 300 cycles, and the 4.5 Ah pouch cell delivers a stable energy density of 321 Wh kg^-1. This cation-π mediated weak solvation chemistry provides valuable guidance for developing high-performance gel polymer lithium batteries.