The Surface Structure of the Proton-Exchanged Lithium Manganese Oxide Spinels and Their Lithium-Ion Sieve Properties

X-Ray Absorption Fine Structure Spectroscopy as a Probe of Local Structure in Lithium Manganese Oxides

“…The redox mechanism of lithium extraction and insertion in LiMn O has been well documented in the literature (4,5,8,14) and was recently discussed in this journal by Clearfield et al (11). In acid solution, LiMn O undergoes disproportionation according to the topotactic reaction (8,14) Li…”

“…The lithium insertion chemistry of these compounds is quite complex. Lithium extraction and insertion may take place with electron transfer and corresponding changes in the oxidation state of the transition metal ions, but also by ion exchange (1,(6)(7)(8)(9)(10)(11). Structural changes at a local level or involving a change in the symmetry of the entire crystalline lattice may also occur.…”

Extracting Tritium from Water Using a Protonic Manganese Oxide Spinel

“…Manganese oxides crystallize to form various phases (9), and the spinel crystal structure in the Fd3m space group adopts the chemical form of LiMn 2 O 4 (10,11). The protonated form (i.e., HMn 2 O 4 ) is obtained when LiMn 2 O 4 makes contact with strongly acidic water (e.g., pH 1-3), and the crystal structure of spinel is maintained during the ion exchange reaction between lithium ions (Li + ) and protons (H + ) or deuterons (D + ) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). In this A c c e p t e d M a n u s c r i p t 3 study, the properties for extracting ionic tritium (T + ) into the crystal structure from water under weakly acidic conditions using a nanosized protonic manganese oxide spinel (PMOS) powder were investigated.…”

Direct Hydrothermal Synthesis of Ternary Li‐Mn‐O Oxide Ion‐Sieves

“…The lithium ion‐sieve effect depends strongly on the crystal structure and morphology of the LiMn 2 O 4 precursor, for which bulky or nanocrystalline MnO 2 with different crystal structures were first synthesized. This was followed by a high‐temperature solid state reaction between decomposable lithium compounds (e.g., lithium carbonate or nitrate) and the MnO 2 to form a LiMn 2 O 4 precursor and an acid treatment process to extract the lithium from the Li–Mn–O lattice to get the final ion‐sieves with selective adsorption capacity for lithium ions 7–12 . However, the final ion‐sieves obtained this way are of irregular morphology and are large aggregates with a broad particle size distribution, resulting from the high‐temperature calcination process and repeated grinding.…”