Structure change of orthorhombic LiMnO₂cathodes during electrochemical cycle for rechargeable lithium battery

The research confirms that the irreversible transformation to spinel-like structure during orthorhombic LiMnO2 cycle is a gradual phase transformation process. A model for the structure change of orthorhombic LiMnO2 during the electrochemical cycle is presented. The model successfully clarified the fact that the 4 V voltage plateau does not exist for the first discharge. Because the LiMnO2 has 124 mAh g–1 of the first charge capacity, there are many Li ions containing the octahedral sites. The tetrahedral sites left by Mn ions migrating would be occupied by lithium ions containing the octahedral sites with further cycle, which make the 4 V voltage plateau developing. According to the model suggestion, the different variants of spinel LixMn2O4 will develop the nanodomain.