Effect of Different Composition on Voltage Attenuation of Li-Rich Cathode Material for Lithium-Ion Batteries

Li-rich layered oxide cathode materials have become one of the most promising cathode materials for high specific energy lithium-ion batteries owning to its high theoretical specific capacity, low cost, high operating voltage and environmental friendliness. Yet they suffer from severe capacity and voltage attenuation during prolong cycling, which blocks their commercial application. To clarify these causes, we synthesize Li_1.5Mn_0.55Ni_0.4Co_0.05O_2.5 (Li_1.2Mn_0.44Ni_0.32Co_0.04O₂) with high-nickel-content cathode material by a solid-sate complexation method, and it manifests a lot slower capacity and voltage attenuation during prolong cycling compared to Li_1.5Mn_0.66Ni_0.17Co_0.17O_2.5 (Li_1.2Mn_0.54Ni_0.13Co_0.13O₂) and Li_1.5Mn_0.65Ni_0.25Co_0.1O_2.5 (Li_1.2Mn_0.52Ni_0.2Co_0.08O₂) cathode materials. The capacity retention at 1 C after 100 cycles reaches to 87.5% and the voltage attenuation after 100 cycles is only 0.460 V. Combining X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM), it indicates that increasing the nickel content not only stabilizes the structure but also alleviates the attenuation of capacity and voltage. Therefore, it provides a new idea for designing of Li-rich layered oxide cathode materials that suppress voltage and capacity attenuation.