Molecular Interlocking Multidimensional Modulations of Cathode‐Electrolyte Interface for Constructing High Energy Density Quasi‐Solid‐State Batteries

Abstract Gel polymers are regarded as a promising candidate electrolyte for lithium‐metal quasi‐solid‐state batteries, primarily due to their high ionic conductivity and solid‐liquid synergistic properties. However, challenges such as interfacial side reactions, limitations in Li⁺ transport caused by interfacial issues, and leaching of transition metals from the cathode have yet to be effectively solved. Herein, a novel gel electrolyte modulation strategy based on electrostatic filler assembly is proposed to address the issues of ineffective capacity utilization and inadequate cycling stability of high‐energy‐density cathode materials in solid‐state lithium‐ion batteries. It constructs a 3D interpenetrating charge‐bridge network that effectively tackles the phase‐separation challenge between fillers and electrolytes at the molecular level. Meanwhile, the molecular interlocking structure effectively inhibits the electrolyte erosion. More critically, it optimizes and stabilizes the cathode‐electrolyte interface film, which facilitates the conduction of Li⁺‐ions through a size‐sieving mechanism. Consequently, this strategy enables effective adaptation across diverse high‐energy‐density cathode materials with satisfactory capacity performance (170.4 mAh g⁻¹ at 4.5 V/1 C for LiNi_0.6Co_0.2Mn_0.2O₂ and 194.0 mAh g⁻¹ at 4.3 V/1 C for LiNi_0.9Co_0.08Mn_0.02O₂). This investigation offers a straightforward and effective reference for addressing the critical challenges of ionic transport and interface stabilization in the design of gel electrolytes.