Hydrogen-bonding mesoporous boehmite orchestrating anion-derived solvation regulation and confinement toward dendrite-free lithium anodes

Abstract Regulating the solvation structure toward anion-derived complex is crucial for building an inorganic-rich solid-state electrolyte interface (SEI) utilized as a dendrite-free lithium anode. Introducing porous materials into the separator is an effective strategy to promote the desolvation of solvated ions as they traverse the pores, thereby addressing key interfacial challenges. Micropores enable effective desolvation; however, they restrict Li + ion mobility. Herein, for the first time, mesoporous boehmite (γ-AlOOH with an average pore size of 3.45 nm) is used to regulate the solvation structure and achieve multifunctional synergy. Typically, the BP/GF separator achieves a Li + ion transference number of 0.61, superior flame retardancy, and an inorganic-dominated SEI (enriched with Li 2 CO 3 , Li 3 N, Li 2 O, and LiF), because the hydroxyl groups on boehmite establish hydrogen bonds with solvent molecules and anions, which effectively promote the desolvation and confine free anions, leading to an increase in anion-derived complex and enhancement of Li + ion transport kinetics, and finally collectively mitigate dendrite formation and stabilize the lithium metal anode. Furthermore, mesoporous boehmite universally regulates solvation structure modulation across Li-S, Li-LiFePO 4, and Li-O 2 batteries, enabling broad-spectrum performance improvements.