Phosphorus-Doped Spinel Cathode for High-Temperature Li-Ion Stability

The patent applies local quality by doping phosphorus specifically at the surface of the spinel particles and using gradient doping where phosphorus concentration decreases from surface to core. This creates different compositions in different regions: the surface has high phosphorus content for stability, while the core maintains high nickel content for voltage. This resolves the contradiction by allowing high working voltage in the core while ensuring long-term stability at the surface.

The patent creates a composite structure by combining phosphorus-doped spinel particles with a protective coating layer containing phosphorus and other elements. This composite material integrates the high-voltage properties of the spinel core with the stabilizing properties of the phosphorus-rich surface and coating, enabling both high working voltage and long-term stability at elevated temperatures.

The patent applies preliminary action by incorporating phosphorus doping into the initial solid-state reaction process rather than adding it separately afterward. The phosphorus-containing compound is mixed with the starting materials before the main sintering step, allowing the doping to occur during the primary synthesis. This preliminary incorporation simplifies the overall manufacturing process while achieving the desired structural stabilization.

The patent uses parameter changes by optimizing the doping ratios of phosphorus and element G, as well as the sintering temperature and time parameters. By carefully controlling these parameters, the patent achieves effective doping and structural stabilization without requiring overly complex multi-step processes. The specific parameter ranges provided in the patent enable reproducible results with relatively simple manufacturing procedures.