Exploring Lithium Deficiency in Layered Oxide Cathode for Li-Ion Battery

초록

The ever-growing demand for high capacity cathode materials is on the rise since the futuristic applications are knocking on the door. Conventional approach to developing such cathode relies on the lithium-excess materials to operate the cathode at high voltage and extract more lithium-ion. Yet, they fail to satiate the needs because of their unresolved issues upon cycling such as, for lithium manganese-rich layered oxides-their voltage fading, and for as nickel-based layered oxides-the structural transition. Here, in contrast, lithium-deficient ratio is demonstrated as a new approach to attain high capacity at high voltage for layered oxide cathodes. Rapid and cost effective lithiation of a porous hydroxide precursor with lithium deficient ratio is acted as a driving force to partially convert the layered material to spinel phase yielding in a multiphase structure (MPS) cathode material. Upon cycling, MPS reveals structural stability at high voltage and high temperature and results in fast lithium-ion diffusion by providing a distinctive solid electrolyte interface (SEI) chemistry-MPS displays minimum lithium loss in SEI and forms a thinner SEI. MPS thus offers high energy and high power applications and provides a new perspective compared to the conventional layered cathode materials denying the focus for lithium excess material.

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