Interface and defect engineering enable fast and high-efficiency Li extraction of metatitanic acid adsorbent

Abstract Considering the striking theoretical Lithium (Li) uptake capacity, environmental benignity and low cost, metatitanic acid (H2TiO3, abbreviated to HTO) is considered to be one of the most promising lithium ion sieve (LIS) adsorbent for liquid-phase Li extraction technology. However, the discouraging adsorption kinetics seriously hampers its industrial application. Herein, the traditional HTO-LIS is promoted by the combined strategies of pore-structure construction, surface heteroatom modification and alien Zn ion bulk doping, which ameliorates the surface characterization of the HTO adsorbent towards fast Li+ capturing from the solution, facilitating the activation and replacement of Li+ on the interface. Further, the oxygen bulk defect originated from Zn doping accelerates the Li+ transfer in solid-phase via the depressed diffusion energy barrier. The interfacial modification and defect engineering synergistically cooperate to extremely speed up the Li extraction process that the Li uptake rate of the optimized sample (PN-HZTO-0.04) increases to 457% compared to the pristine HTO-0 adsorbent. Remarkably, in the optimized Solid/Liquid ratio adsorption test, the adsorption efficiency of above 96% are achieved in 2 h, without obvious capacity degradation and Ti dissolution loss during adsorption/desorption cycles, representing excellent recycling ability.