Effect of Y(PO3)3 double-coating modification on the electrochemical properties of Li[Ni0.8Co0.15Al0.05]O2
Aiming at the difficulty that the alkaline substances left on the surface of Li[Ni0.8Co0.15Al0.05]O2(NCA)pre-cursor preparation and lithium preparation sintering process can seriously affect its cycling stability performance,a proposal was made to employ Y(PO3)3 for surface coating modification.This modification involves utilizing Y(PO3)3 to react with the surface residual LiOH to eliminate surface residual alkali and investigate the impact mechanism of coating modification on the overall performance of NCA.The thickness of the cladding layer was not affected by the residual alkali content on the surface.Test analysis results demonstrate that during low-temperature calcination,a uniform and dense coating layer of Y(PO3)3 and LiPO3 formed on the precursor's surface.LiPO3 exhibited higher ion-ic conductivity,and the dual coating layer can prevent harmful side reactions between the active material and the electrolyte during the electrochemical cycling process,enhancing the cycling stability of the electrode material.Spe-cifically,for samples with a mass fraction of 1％Y(PO3)3 coating,at 0.1C,the initial Coulombic efficiency increased from 78.65％for unmodified samples to 88.50％.After 150 cycles at 1C,the capacity retention rate increased from 59.38％to 85.33％.Compared to unmodified samples,it showed higher initial Coulombic efficiency and superior cycling performance.
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