Lithium extraction from salt lakes has become a hot research issue in recent years, and LiMn 2 O 4 -based electrochemical lithium extraction is considered to be one of the most promising technologies for application. However, LiMn 2 O 4 limits its further application due to the dissolution of Mn and the Jahn-Teller effect. In this study, a LiNi 0.05 Mn 1.95 O 4 (LNMO-0.05) lithium-extraction electrode material with truncated octahedral characteristics was prepared. The special crystal surface structure enhanced the diffusion and adsorption rates of Li + , whereas Ni doping effectively suppressed the Jahn-Teller effect, and the two mechanisms synergistically enhanced the lithium extraction performance of LMO. In lithium extraction from East Taijiner brine with an Mg/Li ratio of 46, LNMO-0.05 showed excellent ion selectivity (α Mg-Li = 214.08), high lithium extraction capacity (20.99 mg/g) and no significant capacity decay occurred after 10 cycles. These excellent properties make the LNMO-0.05 electrode suitable for industrial electrochemical lithium extraction.
Current explosive demand in raw lithium greatly boosts lithium mining, and electrochemical Li-extraction using spinel LiMn 2 O 4 (LMO) from original brine has gained much attentions. In this study, Cr-doped LMO is prepared via a facile precipitation-calcination to elucidate the structural alterations and suppress Jahn-Teller distortion, and a novel hybrid capacitive deionization (HCDI) system of “Li-poor LiMn 1.8 Cr 0.2 O 4 ||brine (recovery liquid)||activated carbon” is constructed for electrochemical Li-extraction. The results prove that Cr-doping effectively suppresses Mn 3+ disproportionation induced by Jahn–Teller distortion, leading to a stabilized spinel framework for long lifespan. Importantly, the Cr-doping LMO realizes a stable (de)lithiation over 500 cycles with low manganese dissolution rate of 0.027% per cycle. Meanwhile, the Li-extraction capacity can reach 22 mg g −1 in 1.0 M LiCl electrolyte with retention rate of 86.05% after 500 cycles. In the assembled HCDI system, average Li-extraction capacity in brine reaches ∼15 mg g −1 after 15 cycles. Therefore, the HCDI system using Cr-doping LMO could introduce a new perspective for the industrial Li-extraction facing original brine.
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