Minimized Metal Dissolution from High-Energy Nickel Cobalt Manganese Oxide Cathodes with Al₂O₃ Coating and Its Effects on Electrolyte Decomposition on Graphite Anodes

High-energy nickel cobalt manganese oxides have been studied intensively as cathode materials for lithium-ion batteries. However, several hurdles need to be overcome to adopt these cathodes in commercial lithium-ion batteries. Herein, aluminum oxide (Al 2 O 3 ) coating was applied to high-energy nickel cobalt manganese oxides (HE-NCM, Li 1.33 Ni 0.27 Co 0.13 Mn 0.60 O 2+d ) by atomic layer deposition (ALD) and its effects on HE-NCM/graphite full cells were investigated. HE-NCM/graphite full cells have better cycling performance and efficiency when HE-NCM is coated with Al 2 O 3 . ICP-MS measurements show that the Al 2 O 3 coating can effectively prevent transition metal dissolution from HE-NCM. XPS and FT-IR analysis suggests that the surface film on HE-NCM cathodes does not change significantly with the Al 2 O 3 coating even after 50 cycles, however the surface film on graphite anodes shows a significant change. The resistance of graphite electrodes cycled with the uncoated HE-NCM is higher than that of graphite electrodes cycled with the Al 2 O 3 -coated HE-NCM due to the increased SEI thickness. The improved cycling performance of HE-NCM/graphite cells with Al 2 O 3 coating can be attributed to the minimized resistance increase on graphite as well as the suppression of cathode active material loss.