Dual-Steric Hindrance Modulation of Interface Electrochemistry for Potassium-Ion Batteries

Electrolyte chemistry regulation is a feasible and effective approach to achieving a stable electrode–electrolyte interface. How to realize such regulation and establish the relationship between the liquid-phase electrolyte environment and solid-phase electrode remains a significant challenge, especially in solid electrolyte interphase (SEI) for metal-ion batteries. In this work, solvent/anion steric hindrance is regarded as an essential factor in exploring the electrolyte chemistry regulation on forming ether-based K+-dominated SEI interface through the cross-combination strategy. Theoretical calculation and experimental evidence have successfully indicated a general principle that the combination of increasing solvent steric hindrance with decreasing anion steric hindrance indeed prompts the construction of an ideal anion-rich sheath solvation structure and guarantees the cycling stability of antimony-based alloy electrode (Sb@3DC, Sb nanoparticles anchored in three-dimensional carbon). These confirm the critical role of electrolyte modulation based on molecular design in the formation of stable solid–liquid interfaces, particularly in electrochemical energy storage systems.