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

• The new ZnAl 2 O 4 -coated LiFePO 4 electrode was prepared by polypropylene glycol-assisted sol-gel method. • The phase analysis and microstructure imaging of ZnAl 2 O 4 @LiFePO 4 electrode were conducted. • XPS and HR-TEM analyses indicated the existence of Zn 2+ , Al 3+ and C as shell layers on LFP nanoparticles. • The coloumbic efficiency of ZnAl 2 O 4 @LiFePO 4 electrode was significantly enhanced from 80% in the 1 st cycle to 99.8% in the 8 th cycle. • The ZnAl 2 O 4 layer played a vital role for improving the structural stability and electrochemical performance of a LFP cathode. The new ZnAl 2 O 4 -coated LiFePO 4 (ZnAl 2 O 4 @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 ZnAl 2 O 4 -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 ZnAl 2 O 4 -coated LFP electrodes crystallized with spherical-like shape. However, the ZnAl 2 O 4 -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 ZnAl 2 O 4 @LFP electrode demonstrated higher charge and discharge capacities ~ 122 and 95 mAhg −1 , respectively. The coulombic efficiency of ZnAl 2 O 4 @LFP electrode was significantly enhanced from 80% in the 1 st cycle to 99.8% in the 8 th cycle, indicating excellent stability over the following cycles. Accordingly, the ZnAl 2 O 4 layer played a vital role for improving the structural stability and electrochemical performance of a LFP cathode. Combined with the admirable electrochemical performance of ZnAl 2 O 4 @LFP, this will attract the interest for the future development of potential cathode materials.