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Revealing the Thermodynamics and Kinetics of In-Plane Disordered Li2MnO3 Structure in Li-Rich Cathodes

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journal contribution
posted on 11.10.2021, 17:04 by Yun-shan Jiang, Fu-da Yu, Lan-fang Que, Liang Deng, Yang Xia, Wang Ke, Yi Han, Zhen-bo Wang
Though cationic and anionic coredox endows Li-rich oxides the ability to break through the capacity limit, the structural basis that predominates the thermodynamic and kinetic behavior is still unclear. Here, we construct in-plane Li/Mn ordered and disordered Li-rich oxides, revealing the thermodynamic origin of Li2MnO3 superstructures and kinetic behavior of lithium storage. We elucidate the thermodynamic formation energies of different Li/Mn lattices ordering states, which guides the experimental synthesis of the target disordered materials. In the disordered Li2MnO3 structure, we confirm that the in-plane Li/Mn disorder structure supports a fast 3D Li+ diffusion network and the time sequence of thermodynamic delithiation in the TM-layer is postponed. The theoretical calculation shows that the negative shift of the d-band center could promote the stabilization of oxygen redox. Thus, the designed disordered material exhibits higher Li+ diffusion kinetics and superior cyclic stability of high capacity. Our results provide new insights and distinctive strategies for designing sustainable Li-rich cathodes.