Asymmetric interchain interaction enables stable all-solid-state PEO-based Li batteries
Poly(ethylene oxide) (PEO)-based all-solid-state polymer electrolytes (SPEs) hold significant promise for high-specific-energy and high-safety Li batteries, yet suffer from poor mechanical robustness and low Li+-conducting efficiency. Aramid nanofibers (ANFs), with exceptional mechanical strength and abundant intramolecular/intermolecular interactions, are effective additives, but their strictly symmetric interchain interactions generate a highly ordered hydrogen-bond network, producing inert aggregates that compromise electrolyte stability. Here, we construct a poly(ethylene glycol) (PEG)-mediated asymmetric interaction between ANF chains. PEG chains introduce weaker H-bonding acceptor sites, higher steric hindrance, and abundant lithiophilic groups, simultaneously disrupting strong symmetric ANF-ANF interactions and creating rapid Li-ion channels. The resulting electrolyte maintains excellent mechanical properties (yield stress of 3.25 MPa) and enables stable cycling of Li||Li symmetric cells for over 1600 h with low polarization voltage. In LCO||Li cells, the electrolyte achieves a capacity retention of 82.7% after 300 cycles at 1 C, markedly higher than the unmodified counterpart (35.5%). This synergistic optimization of interfacial compatibility and mechanical performance demonstrates a practical route toward safe, high-energy-density all-solid-state polymer batteries.