Electron-funnel mediated anion confinement enables ultra-reversible interphases in solid-state batteries

Solid-state lithium metal batteries face challenges from irreversible interfacial degradation and sluggish ion transport. We propose an electron-funnel-mediated anion confinement strategy via atomic-level electronic field engineering. Incorporating electron-withdrawing –NO₂ groups into Zr-based frameworks induces a 0.38 eV upward d-band center shift, generating a quantum-confined electrostatic gradient that polarizes TFSI⁻ anions. This reduces TFSI⁻ decomposition energy barrier (ΔG: −0.35 → −1.22 eV), selectively promoting LiF nucleation while suppressing side reactions. Concurrently, Zr⁴⁺-PEO Lewis interactions disrupt polymer crystallinity, enhancing ionic conductivity and Li⁺ transference number. Cryo-TEM tomography and TOF-SIMS mapping reveal a fractal LiF-rich interphase enabling dendrite-free lithium plating for > 11,000 h with polarization < 40 mV. LiFePO₄ full cells achieve 86.3% capacity retention after 400 cycles at 1C (1.3 mAh cm⁻²). This work establishes anion confinement as a universal framework synchronizing ion transport and interfacial durability, advancing practical solid-state batteries with exceptional longevity.