biostudies-literatureUnknown62(5)Fan YThe application of Li-rich layered oxides is hindered by their dramatic capacity and voltage decay on cycling. This work comprehensively studies the mechanistic behaviour of cobalt-free Li<sub>1.2</sub> Ni<sub>0.2</sub> Mn<sub>0.6</sub> O<sub>2</sub> and demonstrates the positive impact of two-phase Ru doping. A mechanistic transition from the monoclinic to the hexagonal behaviour is found for the structural evolution of Li<sub>1.2</sub> Ni<sub>0.2</sub> Mn<sub>0.6</sub> O<sub>2,</sub> and the improvement mechanism of Ru doping is understood using the combination of in operando and post-mortem synchrotron analyses. The two-phase Ru doping improves the structural reversibility in the first cycle and restrains structural degradation during cycling by stabilizing oxygen (O<sup>2-</sup> ) redox and reducing Mn reduction, thus enabling high structural stability, an extraordinarily stable voltage (decay rate <0.45 mV per cycle), and a high capacity-retention rate during long-term cycling. The understanding of the structure-function relationship of Li<sub>1.2</sub> Ni<sub>0.2</sub> Mn<sub>0.6</sub> O<sub>2</sub> sheds light on the selective doping strategy and rational materials design for better-performance Li-rich layered oxides.Angewandte Chemie (International ed. in English)e202213806https://www.ebi.ac.uk/biostudies/studies/S-EPMC10108050biostudies-literatureStabilizing Cobalt-free Li-rich Layered Oxide Cathodes through Oxygen Lattice Regulation by Two-phase Ru Doping.PMC10108050Cowie BZhang FCai QOlsson ELi JFan YGuo ZD'Angelo AMZhao YJohannessen BThomsen LLiang GPang WKWang ZfalseStabilizing Cobalt-free Li-rich Layered Oxide Cathodes through Oxygen Lattice Regulation by Two-phase Ru Doping.The application of Li-rich layered oxides is hindered by their dramatic capacity and voltage decay on cycling. This work comprehensively studies the mechanistic behaviour of cobalt-free Li<sub>1.2</sub> Ni<sub>0.2</sub> Mn<sub>0.6</sub> O<sub>2</sub> and demonstrates the positive impact of two-phase Ru doping. A mechanistic transition from the monoclinic to the hexagonal behaviour is found for the structural evolution of Li<sub>1.2</sub> Ni<sub>0.2</sub> Mn<sub>0.6</sub> O<sub>2,</sub> and the improvement mechanism of Ru doping is understood using the combination of in operando and post-mortem synchrotron analyses. The two-phase Ru doping improves the structural reversibility in the first cycle and restrains structural degradation during cycling by stabilizing oxygen (O<sup>2-</sup> ) redox and reducing Mn reduction, thus enabling high structural stability, an extraordinarily stable voltage (decay rate <0.45 mV per cycle), and a high capacity-retention rate during long-term cycling. The understanding of the structure-function relationship of Li<sub>1.2</sub> Ni<sub>0.2</sub> Mn<sub>0.6</sub> O<sub>2</sub> sheds light on the selective doping strategy and rational materials design for better-performance Li-rich layered oxides.2023-01-01T00:00:00Z2023 Jan2025-04-18T15:00:55.25Z2025-04-07T01:27:16.74ZS-EPMC101080503645652910.1002/anie.202213806