Dual‐Descriptor Tailoring: Rational Solvent Molecule Tuning Enables High‐Voltage Li‐Ion Batteries

Abstract Electrolyte engineering to enhance the cathode‐electrolyte interface stability is widely recognized as a promising strategy for achieving high‐voltage lithium‐ion batteries, which are currently hindered by the meta‐stable surface of lithium‐rich layered oxides. Despite significant progress in electrolyte development, clear design guidelines for high‐voltage electrolytes remain lacking, making solvent selection unpredictable. Here, a dual‐descriptor tailoring concept based on Mulliken charge (adsorption) and Laplacian bond order (antioxidation) to identify ideal solvent molecules for high‐voltage electrolytes is proposed. This concept stabilizes meta‐stable transition metal atoms in surface tetrahedral interstices through interactions between bottom solvent molecules and cathode dangling bonds. Acetonitrile (AN) is eventually selected as a promising bottom solvent that interacts strongly with unstable surface bonds, improving interfacial stability. Consequently, the prepared 0.6 Ah graphite||LCO pouch cell using AN‐based electrolyte maintained a remarkable 80% capacity retention after 900 cycles with an average Coulombic efficiency of 99.92% at high cut‐off voltage. This work revisits the interfacial stability mechanism across different electrolyte classes, where strong solvent adsorption mitigates the instability of the meta‐stable Co spin state, reduces surface band overlap, and alleviates the instability of lattice oxygen at the interface. This dual‐descriptor‐guided design opens a new avenue for high‐voltage Li‐ion batteries is believed.