Composite Oxide Cathode Processing for Low-Temperature Li-Ion Discharge

The patent applies parameter changes by precisely controlling the particle size of lithium cobalt oxide (median diameter ≤10 μm) and implementing multi-stage heating processes at specific temperature ranges (700-1000°C for first heating, 800-1100°C for second heating, 800-950°C for third heating). These parameter optimizations enable the positive electrode active material to maintain high discharge capacity and energy density even at low temperatures below 0°C

The patent creates a composite material structure by forming a coating layer containing fluorine, magnesium, nickel, and aluminum on the lithium cobalt oxide particles through sequential mixing and heating steps. This composite structure combines the high capacity of lithium cobalt oxide with the low-temperature performance enhancement from the multi-element coating, resolving the contradiction between room temperature operation and low-temperature discharge capacity

The patent implements periodic action through a multi-stage heating process with distinct temperature ranges and duration periods: first heating at 700-1000°C for 1-5 hours, second heating at 800-1100°C for 1-10 hours, and third heating at 800-950°C for 1-5 hours. Each stage serves a specific purpose in forming the composite structure while controlling total processing time, achieving crystal structure stability without excessive time loss

The patent applies preliminary action by conducting the first heating step before adding the fluorine, magnesium, nickel, and aluminum sources. This preliminary thermal treatment prepares the lithium cobalt oxide substrate, ensuring proper crystal structure formation before the subsequent coating layers are applied and heated, thereby optimizing the overall manufacturing efficiency