Molybdenum-doped manganese-based ion sieves for enhanced liquid lithium extraction performance

Manganese-based lithium-ion sieves (LISs) exhibit remarkable potential for lithium extraction from salt lakes owing to their excellent adsorption properties and high selectivity. However, manganese dissolution severely limits the industrial application of manganese-based LISs. Herein, a series of molybdenum (Mo)-doped manganese-based LISs (LMMO-X%) with high adsorption capacity were synthesised using the sol-gel method. Results indicate that the introduction of Molybdenum atom enhances the Mn(IV) content in the material while promoting the growth of the (111) crystal plane of Li 4 Mn 5 O 12 and suppressing the growth rates of the (110) and (100) crystal planes. Compared to the undoped ion sieve, the lithium adsorption capacity of the Mo-doped material increased from 35.56 to 44.63 mg/g, while the manganese dissolution rate decreased from 3.79 % to 2.63 %, considerably improving the overall performance of the LIS adsorbent. X-ray diffraction and X-ray photoelectron spectroscopy confirmed that Mo was successfully doped into the material, increasing the Mn(IV) content from 35.3 % to 56.5 %, enhancing the structural stability of the material and alleviating the Jahn–Teller distortion during the acid elution process. In addition, the adsorption process follows a pseudo-second-order kinetic model and the Langmuir isotherm adsorption model. In competitive salt solutions, LMMO demonstrates excellent selectivity for Li + and retains 80.73 % of its adsorption capacity after 10 cycles. This study provides a novel strategy for enhancing the structural stability of doping-modified materials.