Uncovering fantastic synergistic lithium adsorption with manganese-titanium based composite nanospheres: Mild synthesis and molecular dynamics simulation insights

Abstract

In light of the burgeoning energy technology sector and the ever-growing demand for lithium across diverse industrial domains, conventional lithium extraction methods have been proven inadequate due to their limited production capacity and high operational costs. This work introduces a novel approach to the manganese-titanium based composite HMTO (Mn:Ti=1:4) lithium ion-sieve (LIS) nanospheres, employing lithium acetate dihydrate, manganese carbonate and titanium dioxide P25 as the primary materials. These nanospheres exhibit relatively uniform spherical morphology, narrow size distribution, small average particle size (ca. 55 nm), large specific surface area (43.58 m² g⁻¹) and high surface O²⁻ content (59.01%). When utilized as the adsorbents for Li⁺ ions, the HMTO (Mn:Ti=1:4) LIS demonstrates a fast adsorption rate, approaching equilibrium within 6.0 h with an equilibrium adsorption capacity (q_e) of 79.5 mg g⁻¹ and a maximum adsorption capacity (q_m) of 87.26 mg g⁻¹ (initial concentration C₀: 1.8 g L⁻¹). In addition, the HMTO (Mn:Ti=1:4) also delivers a high lithium extraction from the simulated high magnesium-lithium molar ratio salt lake brine (Mg:Li = 103), achieving a q_e of 33.85 mg g⁻¹ along with a remarkable selectivity (${\alpha }_{\mathrm{Mg}}^{\mathrm{Li}}=2192.76$). Particularly, the HMTO (Mn:Ti=1:4) LIS showcases a satisfactory recycling adsorption performance. The adsorption capacity remains at a high level, even that determined after the 5th cycle (55.45 mg g⁻¹) surpasses that of the most recently reported adsorbents. Ultimately, the fantastic synergistic lithium adsorption mechanism is deliberately uncovered by leveraging the ion exchange principles and molecular dynamics (MD) simulations.