Hyper‐Areal‐Capacity Dry Electrodes (22.6 mAh cm ⁻² ) Enabled by Electron Beam‐Induced Functionalization of Fibrillated PTFE for High‐Energy‐Density Li‐ion Batteries (>400 Wh kg ⁻¹ )

Abstract The dry‐processing method using polytetrafluoroethylene (PTFE) binders is considered a promising approach in fabricating high‐loading electrodes for high‐energy‐density lithium‐ion batteries (LIBs). However, the fluorinated surface of PTFE resists wetting by conventional electrolytes, hindering ion transport and inducing nonuniform electrochemical reactions across the entire electrode. Here, an innovative strategy is presented to convert the hydrophobic surface of fibrillated PTFE, even those deeply embedded in thick electrodes, into an electrolyte‐compatible interface bearing hydrophilic ─COOH and ─C═O groups, via direct application of electron beam (EB) irradiation to postfabricated dry electrodes. This EB irradiation strategy applied to the fabricated dry electrodes is rapid, solvent‐free, and highly penetrable. Thus, it is highly compatible with the dry electrode manufacturing process, directly addressing sustainability and cost challenges. Benefiting from the improved wettability, the EB‐irradiated dry electrodes exhibited markedly enhanced and uniform Li‐ion migration throughout the thick electrode, thereby delivering superior electrochemical performance even for hyper‐loaded electrodes (100 mg cm −2 , 22.6 mAh cm −2 ), exhibiting stable cycling performance with 89.51% capacity retention, achieving cell‐level energy density of 449.4 Wh kg −1 . This strategy offers a crucial pathway toward high‐energy‐density batteries as it overcomes the inherent challenges of dry electrodes without compromising the environment‐friendly and sustainable nature of dry processing.