Fully activated Li2MnO3 nanoparticles by oxidation reaction

Fully activated Li2MnO3 nanoparticles were prepared by a chemical based oxidation reaction. All of the diffraction peaks of the prepared samples were well matched to a monoclinic phase (space group: C2/m) with no impurity peaks and refined using the General Structure Analysis System (GSAS) program. The activated Li2MnO3 sample showed homogeneously well-dispersed nanoparticles with a size of similar to 10 nm. The oxidation state of Mn was confirmed by XPS. The activated Li2MnO3 nanoparticles delivered a high charge capacity of 302 mA h g(-1) above 4.5 V and discharge capacity of 236 mA h g(-1) during the first cycle. Interestingly, the cycle performance of the activated Li2MnO3 nanoparticles during extended cycles exhibited somewhat stable discharge capacities without any drastic capacity fading, even when cycled in the high voltage range of 2.0-4.9 V and after the phase transition to spinel. In terms of the rate performance, the activated Li2MnO3 sample exhibited significantly superior properties compared to the bulk Li2MnO3 sample, probably due to the nano-size particles with high crystallinity.