Synthesis and Adsorption Properties of Li1.6Mn1.6O4 Spinel

Orthorhombic-LiMnO2, spinel-type Li1.6Mn1.6O4, and spinel MnO2·0.5H2O were synthesized via a combination of hydrothermal synthesis and solid-phase reaction. o-LiMnO2 with different stacking fault concentrations were synthesized by controlled hydrothermal reaction using a KMnO4, MnCl2, and LiOH mixed solution. Spinel-type Li1.6Mn1.6O4 precursor was prepared via heat treatment of o-LiMnO2. The effects of hydrothermal and solid-phase reaction on the structure and ion-exchange properties were examined with powder X-ray diffraction, scanning electron microscopy, and Li+ selective adsorption measurements. The results showed that stacking fault concentration of o-LiMnO2 affects the adsorption properties of Li1.6Mn1.6O4. Li+ adsorption capacity reached 6.06 mmol·g–1 at equilibrium. Distribution coefficients of metal ions were in the order Li+ ≫ Na+ > Mg2+ > K+ > Ca2+ and were significant for Li+ extraction from low grade brine. The equilibrium uptake of Li+ from salt lake brine remained at 3.62 mmol·g–1 after six cycles.