Improved cycleability of LiMn2O4-based thin films by Sn substitution.

The spinel thin films of LiSn_x/2Mn_2-xO₄ prepared by pulsed laser deposition were studied in regards with electrochemical reversibility and discharge capacity. LiSn_0.0125Mn_1.975O₄ thin films possessed a large capacity of ∼120 mA h g^-1 and a high capacity retention of >81% relative to their initial capacity at 4 C after the 90th cycle. Such promising results are believed to originate from the Mn⁴⁺-richer spinel structure and the less distortion of MnO₆ octahedra. The near-edge x-ray-absorption fine structure result of the cycled LiSn_0.0125Mn_1.975O₄ films can be highlighted with the specific local t_2g symmetry resulting from the interaction between Mn 3d and O 2p. [ABSTRACT FROM AUTHOR]