Enhancing Lithium-Ion Battery Performance: Nano Al2O3 Film Deposition on High Mass Loading LiFePO4 Cathode Electrode Using Atomic Layer Deposition Technique

Abstract

Lithium iron phosphate (LiFePO₄ or LFP) is a promising cathode material for lithium-ion batteries (LIBs), but side reactions between the electrolyte and LFP electrode can degrade battery performance. This study introduces an innovative coating strategy using atomic layer deposition (ALD) to apply a thin (5nm and 10nm) Al₂O₃ layer on high mass loading LFP electrodes. Galvanostatic charge-discharge cycling and Electrochemical Impedance Spectroscopy (EIS) were used to assess the electrochemical performance of coated and uncoated LFP electrodes. The results show that Al₂O₃ coatings enhance cycling performance at room temperature (RT) and 40°C by suppressing side reactions and stabilizing the cathode-electrolyte interface (CEI). The coated LFP retained 67% of its capacity after 100 cycles at 1C and RT, compared to 57% for the uncoated sample. Post-mortem analyses, including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), were conducted to investigate the mechanisms behind the improved performance. These analyses reveal that the Al₂O₃ coatings are highly effective in reducing LFP electrode degradation during cycling, demonstrating the potential of ALD Al₂O₃ coatings to enhance the durability and performance of LFP electrodes in LIBs.