Unraveling the Li+ desorption behavior and mechanism of Li4Ti5O12 with different facets to enhance lithium extraction

Abstract

Lithium extraction from liquid resources has drawn significant attention owing to the availability of abundant deposits. However, developing highly efficient Li⁺ adsorbent materials is limited by the unclear chemical mechanism correlating the adsorbent material structure and ion adsorption performance, as well as the diffusion mechanism of ions in the bulk phase of the material. Here, by fabricating three kinds of adsorbent precursors Li₄Ti₅O₁₂ (LTO) with different exposed planes, we reveal the internal mechanism that links the material structure and Li⁺ desorption performance. The LTO with the 110 planes exhibited the highest Li⁺ desorption efficiency of 98%, and the corresponding desorption product H₄Ti₅O₁₂ (HTO) with 110 is more likely to adsorb Li⁺ as it delivered adsorption capacity up to 37.58 mg g⁻¹. The structural analysis reveals that more 8a sites were exposed on the 110 planes of the material, and the density functional theory (DFT) results clarify that Li⁺ diffusion to the 8a sites is favored (0.40 eV). Our work not only uncovers the mechanism that connects the material structure and ion ad/desorption performance but also paves the way for designing efficient and advanced Li⁺ adsorbents to assist lithium resource extraction.