Gradient Li-rich Cathode Particles with Suppression of Voltage Decay by High-Temperature Leaching of LiO

Previous hybrid-anion and cation-redox (HACR) cathodes were limited in cycling performance by irreversible anionic redox reactions cause by the loss of anions. To overcome this limitation, a lithium (Li) transition metal (M) oxide particle is described having a Li concentration gradient. In one example, the particle includes a Li-rich core region that provides capacity and energy density due anionic and cationic contributions and a Li-poor surface region surrounding the core region to inhibit anionic activity and thus substantially reduce the loss of anions. A gradient region disposed between the core and surface regions has a Li concentration profile that varies from a first Li concentration in the core region to a second Li concentration in the surface region. A high-temperature leaching method may be used to leach LiO from a Li-rich Li1+xM1-xO2 particle, thus forming a coherent Li gradient with a stabilized layered structure.