Li‐Ions Pre‐intercalation Strategy of Manganese Oxides for Capacitive Deionization‐Based Selective Lithium Extraction From Low‐grade Brine
Yang Bao, Zhixing Ji, Hongru Zhou, Cui Zhang, Shaoxian Song, Feifei Jia, Jianbo Li, Mildred Quintana
Abstract
Abstract In this work, Li preintercalated λ‐Li x MnO 2 with tunable lithium content is synthesized, which exhibited excellent electrochemical performance and dual‐mode electrochemical storage behavior. Double‐layer capacitive and diffusion‐controlled Faradaic processes play a role in the charge–discharge process, leading to an enhanced lithium selective adsorption capacity. When employed in hybrid capacitive deionization (HCDI), the λ‐Li 1.5 MnO 2 obtains a Li + adsorption capacity of 33.68 mg g −1 in 32.74 mg L −1 Li + ion solution and low energy consumption of 0.19 Wh g −1 . Moreover, the λ‐Li 1.5 MnO 2 electrode exhibited outstanding cycling stability, with a significant capacity retention rate of 80% and a manganese mass dissolution rate of 1.2% over 100 intercalation/deintercalation cycles. λ‐Li 1.5 MnO 2 achieved outstanding lithium selectivity with a separation factor ≈32.7 at a Mg 2+ /Li + molar ratio of 30 in synthetic brine. Importantly, λ‐Li 1.5 MnO 2 achieved a high Li + adsorption capacity and good selectivity in Lop Nor, the low‐grade original brine of the XieLi salt flats, making it a candidate electrode for lithium extraction from low‐grade original brine. The pre‐intercalation strategy offers a viable option for rationalizing other intercalation electrode materials for electrochemical lithium extraction from low‐grade original brine.