Dual-descriptor-guided dopant engineering of layered titanate ion sieves for enhanced stability and lithium uptake

Lithium-ion sieve (LIS) technologies for lithium recovery from brines are attracting attention owing to their high selectivity and environmental benefits. Among LIS materials, layered lithium–titanium oxide (LTO) and its delithiated analog, hydrogen titanate (HTO), exhibit favorable structural robustness. However, HTO commonly suffers from Ti dissolution, framework degradation during cycling, and limited Li adsorption capacity. Here, we establish a cell shape-fixed structural optimization scheme that improves density functional theory modeling of interlayer interactions, enabling reliable evaluation of dopant effects in M-doped LTO/HTO systems (M = Sb, Mg, Ni, Mn, Al, Cr, Fe, Co). Structural stability was assessed using dual descriptors: absolute desorption energies and their variations across the LTO/HTO transition. Sb was predicted to be the most promising candidate among the screened dopants, enhancing Ti stability in HTO (9.59 eV) while lowering transition sensitivity (2.29 eV). Experiments confirmed suppressed Ti dissolution and improved cycling stability; 20% Sb-HTO achieved Li uptakes of 32.9 mg/g and 590 mmol/mol, exceeding those of pristine HTO.