Mechanisms and applications of layer/spinel phase transition in Li- and Mn-rich cathodes for lithium-ion batteries

Li- and Mn-rich (LMR) cathode materials have received tremendous attention due to the highly reversible specific capacity (> 250 mAh.g(-1)). In the analysis of its crystal structure, the two-phase composite model gains increasing acceptance, and the phase transition behaviors in LMR cathode materials have been extensively studied. Herein, the structure controversy of LMR cathode materials, and the mechanisms of phase transition are summarized. Particularly, the causes of initiating or accelerating the phase transition of LMR cathode materials have been summarized into three main driving forces, i.e., the electrochemical driving force, the component driving force and the thermodynamic driving force. Additionally, the applications of phase transition behavior in improving the electrochemical performance of LMR cathode materials, including the construction of spinel surface coating and spinel/layered hetero-structure are discussed.