Restraining Lattice Distortion of LiMn<sub>2</sub>O<sub>4</sub> Facilitates Fluidic Electrochemical Lithium Extraction from Seawater
Yongtai Xu, Yixiang Li, Xiaoyu Zhao, Yifan Li, Xue Liang Li, Jing Wang, Hui Ying Yang
Abstract
Reversible electrochemical extraction using cathode materials shows great potential for selective lithium extraction from low-concentration aqueous sources. However, ion selectivity and structural distortion challenges have limited its application to sources like seawater. Here, we synthesize Nb-modified LiMn 2 O 4 using a simple wet chemistry coating method, introducing minimal structural defects in the LiMn 2 O 4 materials and enhancing stability with a LiNbO 3 coating to limit lattice expansion. Additionally, operando XRD reveals reduced lattice distortion during Li + intercalation/deintercalation. Electrochemical tests show that the composite achieves high stability (over 100 cycles), fast Li + electrosorption, and robust ion selectivity. Furthermore, utilizing a fluidic electrochemical approach, we extract lithium from simulated seawater (3.5 ppm of Li + ), achieving an absorption capacity of 13.8 mg g –1 and an energy consumption of 9.96 Wh g –1 .