Impact of Aluminum Added to Ni-Based Positive Electrode Materials by Dry Particle Fusion

This work reports two relatively new approaches to synthesize LiNi1–xAlxO2 materials. The first is coating Al2O3 on a Ni(OH)2 precursor by dry particle fusion followed by heating with LiOH·H2O. The second is coating Al2O3 on LiNiO2 by dry particle fusion followed by heating. X-ray diffraction (XRD), cross-sectional scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) mapping, and EDS line scans were carried out. Coin-type cells were made to test the electrochemical performance of the synthesized materials. It was shown that Ni(OH)2 coated with 1, 2, and 3% Al2O3 followed by heating with LiOH·H2O had better capacity retention than samples prepared by coating on LiNiO2 directly. Of all of the samples prepared, Ni(OH)2 coated with 3% Al2O3, followed by heating with LiOH·H2O had the largest specific discharge capacity and the best capacity retention. The reproducibility of this approach was verified by preparing two more batches of Ni(OH)2 coated with 3% Al2O3 followed by heating with LiOH·H2O in the same way. This work suggests that coating desired materials on precursors by dry particle fusion is an attractive approach for synthesizing next-generation positive electrode materials.