Direct observation of the ultrafast formation of cation-disordered rocksalt oxides as regenerable cathodes for lithium-ion batteries

Lithium-rich cation-disordered rocksalt (DRX) oxides offer promising prospects of satisfying boosting demand for high performance lithium-ion batteries. We introduce a time- and energy-saving high temperature shock synthesis for fast fabrication of these materials, which occurs through formation of binary oxides undergoing transformation to DRX oxides. Variations of morphology, elemental distribution, and microstructure of DRX oxides during the synthesis were followed using the in-situ transmission electron microscopy. The compositional space of DRX oxides varied from binary to senary, demonstrating that the high temperature shock strategy is a general process for their synthesis. Moreover, we demonstrated how the cycling life of DRX oxide cathodes applied in lithium-ion batteries could be extended through recrystallization of their collapsed lattice structure, and this regeneration process was accomplished using the same high temperature shock strategy. The specific capacity of the regenerated cathodes could be recovered to 91.4% of the initial value. Thus, our study offers a general strategy for not only synthesizing DRX oxides but also regenerating the respectively spent cathodes to extend the cycling life of lithium-ion batteries.