Highly Lithium Adsorption Capacities of H 1.6 Mn 1.6 O 4 Ion‐Sieve by Ordered Array Structure

Recovery of Li and Co in Waste Lithium Cobalt Oxide-Based Battery Using H1.6Mn1.6O4

H_1.6Mn_1.6O₄ lithium-ion screen adsorbents were synthesized by soft chemical synthesis and solid phase calcination and then applied to the recovery of metal Li and Co from waste cathode materials of a lithium cobalt oxide-based battery. The leaching experiments of cobalt and lithium from cathode materials by a citrate hydrogen peroxide system and tartaric acid system were investigated. The experimental results showed that under the citrate hydrogen peroxide system, when the temperature was 90 °C, the rotation speed was 600 r·min^-1 and the solid-liquid ratio was 10 g·1 L^-1, the leaching rate of Co and Li could reach 86.21% and 96.9%, respectively. Under the tartaric acid system, the leaching rates of Co and Li were 90.34% and 92.47%, respectively, under the previous operating conditions. The adsorption results of the lithium-ion screen showed that the adsorbents were highly selective for Li⁺, and the maximum adsorption capacities were 38.05 mg·g^-1. In the process of lithium removal, the dissolution rate of lithium was about 91%, and the results of multiple cycles showed that the stability of the adsorbent was high. The recovery results showed that the purity of LiCl, Li₂CO₃ and CoCl₂ crystals could reach 93%, 99.59% and 87.9%, respectively. LiCoO₂ was regenerated by the sol-gel method. XRD results showed that the regenerated LiCoO₂ had the advantages of higher crystallinity and less impurity.

Al-doped H2TiO3 ion sieve with enhanced Li+ adsorption performance

H₂TiO₃ (HTO) is considered to be one of the most promising adsorbents for lithium recovery from aqueous lithium resources duo to its highest theoretical adsorption capacity. However, its actual adsorption capacity is much lower owing to its unknown structure and incomplete leaching of lithium. After Al is doped into H₂TiO₃ (HTO-Al), the adsorption capacity of HTO-Al is 32.12 mg g⁻¹ and the dissolution of Ti is 2.53%. HTO-Al has good adsorption selectivity, and all the separation factors α are ≫1. Furthermore, HTO-Al also exhibits good cyclic stability and solubility resistance. After 5 cycles, the adsorption capacity remains 29.3 mg g⁻¹ and the dissolution rate is 1.7%. Therefore, HTO-Al has potential application value for recovering Li⁺ from aqueous lithium resources.

H₂TiO₃ (HTO) is considered to be one of the most promising adsorbents for lithium recovery from aqueous lithium resources duo to its highest theoretical adsorption capacity.

The adsorption behavior of lithium on spinel titanium oxide nanosheets with exposed (1-14) high-index facets

The ion-exchange process is usually influenced by the surface properties of the adsorbents. In particular, the prophase adsorption/desorption process is confined by different crystal facets. In this research, spinel Li4Ti5O12 nanosheets with an exposed (1-14) high-index facet were prepared by a hydrothermal method followed by calcination treatment. Then, a H4Ti5O12 adsorbent was obtained, covered with the same (1-14) facets, after treatment with 0.2 M HCl. This special facet-exposed H4Ti5O12 has high cycling ability, with the adsorption uptake remaining at 96.84% after four cycles, a fast adsorption equilibrium time (equilibrium time < 60 min), excellent ion adsorption selectivity for Li+ uptake (separation factor: Li+ > K+ > Ca2+ > Na+ > Mg2+), and good adsorption capacity for Li+ uptake (21.57 mg g-1 ). With the help of X-ray photoelectron spectroscopy analyses, the Li+ adsorption process on the H4Ti5O12 nanosheets is shown to be an ion-exchange process. In addition, the coordination relationship between lithium and oxygen ions was investigated, illustrating that the four-coordinated structure is more stable than other complexes. These results indicate that hydrogen ions are exchanged for lithium ions at tetrahedral 8a sites, leading to the H4Ti5O12 structure with high stability in the adsorption-desorption cycling process.

Hydrothermal synthesis and adsorption behavior of H4Ti5O12 nanorods along [100] as lithium ion-sieves

The adsorption method is a promising route to recover Li⁺ from waste lithium batteries and lithium-containing brines. To achieve this goal, it is vital to synthesize a stable and high adsorption capacity adsorbent. In this work, Li₄Ti₅O₁₂ nanorods are prepared by two hydrothermal processes followed by a calcination process. Then the prepared Li₄Ti₅O₁₂ nanorods are treated with different HCl concentrations to obtain a H₄Ti₅O₁₂ adsorbent with 5 μm length along the [100] direction. The maximum amount of extracted lithium can reach 90% and the extracted titanium only 2.5%. The batch adsorption experiments indicate that the H₄Ti₅O₁₂ nanorod maximum adsorption capacity can reach 23.20 mg g⁻¹ in 24 mM LiCl solution. The adsorption isotherms and kinetics fit a Langmuir model and pseudo-second-order model, respectively. Meanwhile, the real adsorption selectivity experiments show that the maximum Li⁺ adsorption capacity reaches 1.99 mmol g⁻¹, which is far higher than Mg²⁺ (0.03 mmol g⁻¹) and Ca²⁺ (0.02 mmol g⁻¹), implying these nanorods have higher adsorption selectivity for Li⁺ from Lagoco Salt Lake brine. The adsorption capacity for Li⁺ remains 91% after five cycles. With the help of XPS analyses, the adsorption mechanism of Li⁺ on the H₄Ti₅O₁₂ nanorods is an ion exchange reaction. Therefore, this nanorod adsorbent has a potential application for Li⁺ recovery from aqueous lithium resources.

H₄Ti₅O₁₂ nanorods were successfully prepared by hydrothermal methods followed by a calcination process. Batch experiments indicate that the nanorod adsorbent is a promising adsorbent to recover lithium from liquid lithium resources.

K-gradient doping to stabilize the spinel structure of Li1.6Mn1.6O4 for Li+ recovery

Li⁺ adsorbent doped with K was prepared and the K entered into the Li_1.6Mn_1.6O₄ (LMO) lattice was confirmed by STEM. DFT calculations further confirmed the K substitution for Li at the 16d sites, which enhanced the stability of LMO.