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.

The recycling of spent lithium-ion batteries (LIBs) is crucial for the sustainable utilization of metal resources. However, challenges such as range anxiety hinder its widespread adoption, thereby driving the pursuit of next-generation energy storage systems with higher energy densities. In this study, we report the development of a trifunctional electrocatalyst, URCA-800, derived from recycled carbon black obtained from ternary LIB cathode materials. The activation process involved vacuum ultraviolet (VUV) irradiation in the presence of melamine as a nitrogen source, enabling effective N-doping and structural modification. Following calcination at 800 °C, the resulting URCA-800 catalyst exhibited enhanced electrocatalytic performance toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and iodine reduction reaction (IRR). Specifically, URCA-800 achieved an ORR half-wave potential of 0.80 V (vs. RHE) and an OER overpotential of 363 mV at a current density of 10 mA cm ^− 2 in 0.1 mol L ^− 1 KOH, comparable to the performance of commercial Pt/C and IrO ₂ catalysts. When applied as a cathode in zinc-air batteries, URCA-800 delivered a high-power density of 196 mW cm ^− 2 and demonstrated excellent operational stability exceeding 400 h. Furthermore, in zinc-iodine batteries, it achieved a high specific capacity of 188.8 mAh g ^− 1 , an impressive iodine utilization efficiency of 89.6%, and outstanding cycling stability over 3,400 cycles. This work presents a scalable and environmentally friendly approach to convert battery waste into high-performance, multifunctional electrocatalysts, offering a promising pathway for advanced energy storage technologies.