Green fabrication of ZnAl2O4-coated LiFePO4 nanoparticles for enhanced electrochemical performance in Li-ion batteries

The new ZnAl2O4-coated LiFePO4 (ZnAl2O4@LFP) electrode was prepared via polypropylene glycol-assisted
sol-gel method and investigated as a cathode material in Li-ion batteries. The pure LFP and ZnAl2O4-coated
LFP electrodes were characterized using XRD, HRTEM, FESEM/EDS/mapping and XPS techniques. XRD data
affirmed the creation of LFP phase with good crystallinity. TEM revealed that the pure LFP and ZnAl2O4-
coated LFP electrodes crystallized with spherical-like shape. However, the ZnAl2O4-coated LFP electrode
offered greater crystallite size than that of pure LFP electrode. The typical atomic state of these electrodes
was examined through XPS. Additionally, EDS analysis provided an actual evidence for the visualization
mapping of each element, signifying the success of coating process on the surface of LFP electrodes.
Furthermore, the ZnAl2O4@LFP electrode demonstrated higher charge and discharge capacities ~ 122 and 95
mAhg−1, respectively. The coulombic efficiency of ZnAl2O4@LFP electrode was significantly enhanced from
80% in the 1st cycle to 99.8% in the 8th cycle, indicating excellent stability over the following cycles. Accordingly, the ZnAl2O4 layer played a vital role for improving the structural stability and electrochemical performance of a LFP cathode. Combined with the admirable electrochemical performance of ZnAl2O4@LFP, this will attract the interest for the future development of potential cathode materials.