Coordination Environment Engineering of Titanium Spinel for Enhanced Lithium Recovery.

Zhao, Bing; Wei, Wenfei; Qiao, Yingjun; Sheng, Xinyue; Xu, Jun; Qian, Zhiqiang; Lv, Baoliang; Liu, Zhong · Nano Lett · 2025

basic_science · Level V

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Abstract

Salt lake lithium extraction accounts for 35% of global Li<sub>2</sub>CO<sub>3</sub> production, but current adsorbents are limited by single coordination environments. Here, we engineer the coordination environment of titanium spinel (H<sub>4-<i>x</i></sub>Li<sub><i>x</i></sub>Ti<sub>5</sub>O<sub>12</sub>, HTO) by selectively exposing (110) and (111) crystal facets to modulate the tetrahedral and octahedral Li<sup>+</sup> sites. The (111) facet exhibits high adsorption capacity (41.34 mg/g), while the (110) facet offers rapid kinetics (equilibrium in 10 min). Density functional theory (DFT) calculations, Raman spectroscopy, and <sup>6</sup>/<sup>7</sup>Li solid-state NMR (ssNMR) spectroscopy reveal that tetrahedral sites lower dehydration energy and enhance mobility, while octahedral sites enable deeper diffusion and higher capacity. Coordination modulation thus enables a synergistic improvement in Li<sup>+</sup> adsorption performance. This work highlights facet engineering as a strategy to enhance ion recovery and guide next-generation adsorbent design.