Ultrafast Laser-Induced Cathode/Electrolyte Interphase for High-Voltage Poly(Ethylene Oxide)-Based Solid Batteries

Poly(ethylene oxide) (PEO)-based solid polymer electrolyte promises interfacial compatibility with the high-capacity metallic anodes in all-solid-state batteries (ASSBs). However, the prototype construction is severely hindered by the parasitic ohmic resistance at the electrode-electrolyte interface, insufficient ionic pathway of the high loading cathode, as well as the PEO oxidation tendency at the high voltage. Herein, a laser-assisted strategy is presented toward ultra-efficient cathode modification (completes within 240 s) by constructing continuous, multi-scale artificial cathode/electrolyte interface (CEI). The tailorable, yet localized temperature gradient induced by the pulsed laser beam can customize the CEI species from the target precursor salts for the on-demand protection purpose. Derived from the tris(trimethylsilyl)phosphate, the proof-of-concept model achieves phosphorus-rich, ion-diffusion network across the high-mass-loading LiNi_0.8Co_0.1Mn_0.1O₂ cathode, which enables the high-rate operation of the ASSBs prototype as well as the extended shelf life at the oxidized idling state. Transmission-mode operando X-ray phase tracking unravels the electrochemical stability origin at the cathode/PEO interface due to the insulation of electron shuttling, where the layered to spinel phase transition and the lattice oxygen release are alleviated. This generic, readily tailorable, highly-efficient laser processing strategy thus provides unprecedented opportunities to secure the varieties of energy-dense, polymer-based ASSBs.