عليرضا كشاورز

The NCM811 cathode material, characterized by its high nickel content, is widely used in lithium-ion batteries due to its significant energy capacity. However, this material faces several challenges, including cation mixing, electrolyte degradation, and insufficient cycling stability. These issues can lead to reduced battery performance and lifespan over time. In this study, a chemical bath deposition method was employed to apply a layer of strontium phosphate on the surface of NCM811 cathode particles to address these challenges. This approach creates a continuous protective coating that acts as a barrier, safeguarding the NCM811 particles from the harmful interactions between the cathode surface and the electrolyte, such as acidic corrosion and surface crack formation. Additionally, the coating enhances the diffusion coefficient of lithium ions during charge/discharge cycles, leading to improved overall battery performance. XRD analysis showed that the application of the strontium phosphate coating did not alter the crystal structure of NCM811, indicating that the coating was applied without negatively affecting the intrinsic structure of the cathode. SEM images of all coated samples revealed that their morphology was spherical, with uniform coverage on the cathode surface. Both Raman spectroscopy and Fourier transform infrared spectroscopy confirmed that the strontium phosphate material was uniformly formed on the cathode surface. Electrochemical performance eva‎luation demonstrated that the strontium phosphate coating, with a thickness of 5.9 nm, significantly improved the cycling stability of the NCM811 cathode material, allowing it to retain 96% of its initial capacity after 100 charge/discharge cycles within the voltage range of 2.8 to 4.4 V at a 1C discharge rate. These results highlight the high potential of protective coatings to enhance the cycling stability and lifespan of lithium-ion batteries.

باتري ليتيم-يون , استرانسيم فسفات , چرخه پذيري

NCM811

Alireza Keshavarz

Dr. Seyed Morteza Masoodpanah