Internal Electric Field Built on Heterointerface of H₂TiO₃/H₄Ti₅O₁₂ Hybrid Enabling Promoted Li Extraction Performance

With potentially high lithium (Li) exchange capacity and long cycle ability, Ti-based oxides of H 2 TiO 3 and H 4 Ti 5 O 12 are considered to be promising Li-ion sieve (LIS) materials applied for Li resource extraction in the liquid phase. However, the LISs usually demonstrate unsatisfactory Li exchange performance under the approximately neutral condition without the strong impetus derived from the rapid combination between OH – in the surrounding solution and H + ionized from LIS. Herein, a hybrid of H 2 TiO 3 /H 4 Ti 5 O 12 with rich phase boundaries is constructed via a facile one-step solid-state method. Owing to the different Fermi energy levels of the two phases, the electrons are transferred at the phase interface between H 2 TiO 3 and H 4 Ti 5 O 12, developing an internal electric field (IEF). The built IEF provides an extra driving force to boost the solid-phase Li + transport, hence enhancing the Li extraction kinetics. Threrfore, the H 2 TiO 3 /H 4 Ti 5 O 12 hybrid exhibits outstanding Li exchange performance of 42.43 and 20.50 mg g –1 under alkaline and neutral conditions, corresponding to the hightest Li extraction rate of 5.30 and 2.05 mg g –1 h –1 reported so far. Our work offers an innovative strategy to promote the Li exchange performance of LIS especially under neutral conditions.