Thermal stability enhancement through structure modification on micro-sized crystalline grains surface of lithium-rich layered oxides

Lithium-rich layered oxides have been considered as the most promising candidate for offering the high specific capacity and energy density for lithium-ion batteries. However, the practical applications are still suffered by the cycle instability and also closely related thermal stability. Here, micro-sized crystalline grains with good dispersion of lithium-rich layered oxides are prepared by molten-salt method, while a spinel structure are also introduced on grains surface by following chemical oxidation and annealing process, and their thermal performance with different cut-off voltages during charge process are systematically studied using differential scanning calorimetry method. Results have shown that thermal stability of micro-sized crystalline grains are better than those of spherical secondary agglomerates, the spinel structure introduction on grain surface of micro-sized crystalline grains can contribute obviously for their thermal stability, in which the onset temperature of exothermic peak has...