Synthesis of Zirconium-Based Material-Coated LiNi0.8Co0.2O2 Cathode Using a New Coating Method

Zr-compound-coated LiNi 0.8 Co 0.2 O 2 is prepared in a single step using a new powder coating process, a modified flame spray pyrolysis method using a water-in-oil emulsion precursor solution. Only the Zr precursor is dissolved in the oil phase and the precursors of LiNi 0.8 Co 0.2 O 2 are dissolved in the water phase. In a flame, precursors in the water phase transform into LiNi 0.8 Co 0.2 O 2 core particles and the Zr precursor in the oil phase transforms into a coating layer on the LiNi 0.8 Co 0.2 O 2 surface. After Zr compound coating, both the electrochemical performance and cycle stability are enhanced because the Zr compound coating layer prevents the oxidation of Ni 3+ of LiNi 0.8 Co 0.2 O 2 by acidic electrolyte. Since the Zr compound material is coated to prevent the Li 2 CO 3 formation on the LiNi 0.8 Co 0.2 O 2 surface, the effectiveness of the Zr compound coating in preventing Li 2 CO 3 formation is investigated. After the as-prepared Zr-compound-coated LiNi 0.8 Co 0.2 O 2 particles and bare LiNi 0.8 Co 0.2 O 2 particles were exposed in an air for a month, the changes in morphologies and structures before and after aging were observed by using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It is confirmed that Zr compound coating effectively reduces the amount of Li 2 CO 3 formation.