Surface-segregated, high-voltage spinel LiMn1.5Ni0.42Ga0.08O4 cathodes with superior high-temperature cyclability for lithium-ion batteries

The substitution of a small amount of Ga in the high-voltage spinel cathode LiMn_1.5Ni_0.42Ga_0.08O₄ leads to superior cyclability at room temperature and 55 °C along with higher rate capability with conventional electrolytes compared to that found with the LiMn_1.5Ni_0.5O₄ cathode. The superior performance is attributed to the segregation of the inert Ga³⁺ ions to the surface during the synthesis process, providing a robust, more stable interface with the electrolyte at the high operating voltage (~ 4.7 V), along with the stabilization of the spinel structure with a disordering of the cations in the octahedral sites.