Abstract: Improving the reversibility of anionic redox and inhibiting irreversible oxygen evolution are the main challenges in the application of high reversible capacity Li-rich Mn-based cathode materials. A facile synchronous lithiation strategy combining the advantages of yttrium doping and LiYO₂ surface coating is proposed. Yttrium doping effectively suppresses the oxygen evolution during the delithiation process by increasing the energy barrier of oxygen evolution reaction through strong Y–O bond energy. LiYO₂ nanocoating has the function of structural constraint and protection, that protecting the lattice oxygen exposed to the surface, thus avoiding irreversible oxidation. As an Li⁺ conductor, LiYO₂ nanocoating can provide a fast Li⁺ transfer channel, which enables the sample to have excellent rate performance. The synergistic effect of Y doping and nano-LiYO₂ coating integration suppresses the oxygen release from the surface, accelerates the diffusion of Li⁺ from electrolyte to electrode and decreases the interfacial side reactions, enabling the lithium ion batteries to obtain good electrochemical performance. The lithium-ion full cell employing the Y^-1 sample (cathode) and commercial graphite (anode) exhibit an excellent specific energy density of 442.9 Wh kg−1 at a current density of 0.1C, with very stable safety performance, which can be used in a wide temperature range (60 to −15 °C) stable operation. This result illustrates a new integration strategy for advanced cathode materials to achieve high specific energy density.

https://doi.org/10.1016/j.gee.2022.06.001