Spatially Selective Solvation Chemistry by Local Charge Enrichment for Stable Potassium-Metal Anodes

Uncontrollable dendrite growth and unstable interface chemistry between the electrode and electrolyte seriously hinder the practical application of potassium metal batteries (PMBs). Herein, a functional intermediate medium comprising molybdenum carbide decorated N-doped carbon (MoC/NC) is designed to preferentially and strongly interact with the KFSI molecules, which causes localized charge rearrangements on its surface and the formation of electron-rich microdomains. It promotes the local accumulation of K⁺ and induces an anions dominant solvation structure, ultimately achieving the construction of SEI rich in inorganic components such as KF. The derived SEI layer effectively suppresses the electron tunneling effect because of the electronic insulation of KF, while the integrated MoC/NC functional intermediate medium facilitates the rapid and balanced K⁺/electron diffusion due to its intrinsic high ionic conductivity. Benefiting from this interfacial synergy, the integrated electrode (MoC/NC@K) exhibits significantly boosted interfacial transport kinetic and uniform potassium deposition behavior. The symmetric cell demonstrates a stable cycling for more than 800 h at 0.5 mA cm^-2, and the cycle stability is also enhanced in the full cells. This work presents innovative concepts and approaches for precisely regulating interface components in PMBs by a multi-scale strategy of molecules and interfaces.