A large amount of cow hair solid waste is produced in leather production, and a reasonable treatment should be developed to reduce the pollution. In this study, cow hair waste was utilized as the carbon precursor, and N₂ was determined to be the most appropriate atmosphere for biochar preparation. We performed a comparison of the properties of biochars that were prepared with different methods, including direct pyrolysis, KOH activation, and the MgO template method. The characterization results show that the highest specific surface area reaches 1753.075 m²/g. Subsequently, the keratin that was extracted from cow hair and purified was used to prepare a biochar with the MgO template method, obtaining an orderly sponge structure. The biochar from cow hair waste was further used to absorb direct blue dye wastewater, and its adsorption capacity reached 1477 mg/g after 10 h with a high efficiency of regeneration. This study successfully utilized keratin-containing hair waste and provides a new source for synthesizing carbon materials for dye wastewater treatment.

Aqueous zinc–iodine batteries (AZIBs) are emerging as highly promising candidates for next-generation, grid-scale energy storage due to the intrinsic safety of water-based electrolytes, the high theoretical capacity of the zinc anode, and the rapid conversion kinetics of the iodine cathode. However, the practical commercialization of AZIBs is severely impeded by formidable interfacial instabilities, including the uncontrollable growth of zinc dendrites, parasitic hydrogen evolution reactions (HER), and the notorious polyiodide (I₃⁻, I₅⁻) shuttle effect. These macroscopic degradation modes are fundamentally rooted in the robust [Zn(H₂O)₆]²⁺ primary solvation sheath and the immense thermodynamic driving force for polyiodide dissolution in highly polar aqueous media. To address these interconnected challenges, electrolyte engineering has evolved into the most potent, holistic strategy. This comprehensive review systematically evaluates the latest advancements in electrolyte engineering for AZIBs. We first deeply decipher the fundamental thermodynamic mechanisms governing Zn²⁺ desolvation and iodine multiphase conversion. Subsequently, we critically analyze cutting-edge regulation paradigms, including water-in-salt (WIS) and localized high-concentration electrolytes (LHCE), cosolvent networks, functional molecular additives, deep eutectic solvents (DES), and quasi-solid-state hydrogels. By integrating in situ/operando spectroscopic characterizations with multiscale theoretical computations (such as MD and DFT), we elucidate the structure–activity relationships at the atomic level. Finally, we provide strategic perspectives on the future trajectories of the field, emphasizing the stabilization of multi-electron (I⁻/I⁰/I⁺) halogen chemistry, AI-driven high-throughput screening, and the rigorous standardization of Ah-level pouch cell engineering for extreme-environment applications.