Latent Solvent-Induced Inorganic-Rich Interfacial Chemistry to Achieve Stable Potassium-Ion Batteries in Low-Concentration Electrolyte.

Low-concentration electrolytes (LCEs) have attracted great attention due to their cost effectiveness and low viscosity, but suffer undesired organic-rich interfacial chemistry and poor oxidative stability. Herein, a unique latent solvent, 1,2-dibutoxyethane (DBE), is proposed to manipulate the anion-reinforced solvation sheath and construct a robust inorganic-rich interface in a 0.5 M electrolyte. This unique solvation structure reduces the desolvation energy, facilitating rapid interfacial kinetics and K intercalation in graphite. Additionally, enhanced anion-cation interactions promote the formation of a thin and robust interfacial layer with excellent cycling performance of potassium-ion batteries (PIBs). Graphite||perylene-3,4,9,10-tetracarboxylic dianhydride full cell exhibits a good capacity retention of 80.3 % after 300 cycles, and delivers a high discharge capacity of 131.3 mAh g even at 500 mA g. This study demonstrates the feasibility of latent solvent-optimized electrolyte engineering, providing a pathway of superior electrochemical energy storage in PIBs.