Characterization and Electrocatalytic Behavior of Layered Li2MnO3 and Its Acid-Treated Form

The material H[H0.18Li0.15Mn0.67]O1.90, obtained by the delithiation of layered Li2MnO3 using acid, gives a 2-fold increase in oxygen reduction ability versus Li2MnO3. Using elemental analysis by the ICP technique, average oxidation state determination, acid−base titrations, and thermal analysis, we determined the chemical composition of the proton-exchanged material to be H[H0.18Li0.15Mn0.67]O1.90. Rietveld refinement shows that the structure of the delithiated material is a monoclinic distortion of the P3 structure resulting in the C2/m space group with cell parameters a =5.049(2) Å, b = 8.707(2) Å, c = 4.903(1) Å, β = 109.17(2)°. The BET surface area for the materials increases from 18 to 57 m2/g upon delithiation. Application of H[H0.18Li0.15Mn0.67]O1.90 as an electrocatalyst in a lithium-air cell gives a specific discharge capacity of 1618 mA h g-1.