Fe-doped H2TiO3 for rapid and efficient lithium extraction from shale gas wastewater

Sustainable lithium-based energy storage and conversion systems, such as lithium-ion batteries, rely on efficient lithium extraction methods from brine sources. Traditional H 2 TiO 3 (HTO) lithium-ion sieves (LIS), though effective, face challenges in optimizing lithium adsorption efficiency and stability. Herein, we introduce a Fe-doping strategy in HTO (Fe-HTO) that artificially substitutes Ti sites, generating lattice defects and oxygen vacancies (OVs). This modification enhances lithium-ion diffusion kinetics and increases active adsorption sites, significantly improving selective lithium extraction efficiency. With Fe-HTO, the equilibrium adsorption time for lithium-ion in shale gas wastewater (SGW), with pH adjustment to 12, is reduced by 20 h compared to undoped HTO. Fe-HTO reaches an adsorption capacity of 37.20 mg/g within 4 h and retains 99.2 % of this capacity after 10 adsorption/desorption cycles at room temperature, demonstrating high structural stability. Density functional theory (DFT) calculations clarify that Fe doping lowers the diffusion energy barrier for lithium-ion, accelerating both lithium-ion diffusion and adsorption. Given this, the work illustrates the potential of heteroatom doping to boost adsorption kinetics, offering promising applications for rapid lithium extraction and similar resource recovery challenges.