Recovery of Degraded Lithium Ion Cathode Particles

This project focuses on recovering the cathode materials of lithium ion batteries through atomic layer deposition (ALD) thin film coating. In industry, when a cathode material for a lithium ion battery are stored, it reacts with CO2 and moisture in the air creating Li2CO3 and LiOH on the particle surface. The harmful substances on the surfaces have a negative impact on battery performance and battery life. In this study, we found that when Li2Ni0.8Mn0.1Co0.1 (Ni-Rich NMC) is exposed to a high amount of moisture it degrades and the performance is reduced. For example, the discharge capacity of Degraded Ni-Rich NMC (DNMC) was much lower than the discharge capacity of pristine Ni-Rich NMC. When applying Al2O3 ALD thin film coating on the surface of DNMC particles, the discharge capacity was able to be restored. According to the electrochemical performance, the 2Al-DNMC (2 cycles of Al2O3 ALD) was able to perform at a similar level as the non-degraded NMC. The increase in performance is likely due to the surface of the DNMC being corroded when exposed to moisture and Al2O3 ALD thin film coating can fix the corroded part, leading to the recovery of discharge capacity. With an Al2O3 ALD film thicker than 2 cycles of ALD, the performance of DNMC was further improved. We will study the coating to figure out the best ratio of coating and then study the mechanism that is driving the increase in performance