Hong, Yeoreum Hong, Seung ki Kim, Sang-Ok Chung, Kyung Yoon Kim, Seung Min Chang, Won Young 2025-05-09T05:30:14Z 2025-05-09T05:30:14Z 2025-05-07 2025-04 1530-6984 https://pubs.kist.re.kr/handle/201004/152378 This study investigates the degradation mechanisms of high-nickel (Ni) layered oxide (LiNi0.83Co0.11Mn0.06O2) under varying discharge C-rates at a high cut-off voltage (4.3 V) during long-term cycling. Contradictory to conventional knowledge, a low discharge rate (0.1C) results in worse cycle performance than a high discharge rate (1C) at a high cut-off voltage. In-depth transmission electron microscopy analysis reveals that at a high C-rate discharge condition, more Ni ions are reduced from +3 to +2, yet the layered structure is maintained. In contrast, at a low C-rate, more Ni ions retain their +3 valence but the phase transition to the periodically ordered spinel occurs at some portion. The prolonged dwell time at high voltage forces Ni ions in Li layers to be locally ordered, and this phase transition more critically affects the cycling. Therefore, this study underscores that setting a proper cut-off voltage can be more significant to the cycle performance than the discharge C-rate. English American Chemical Society Performance Degradation Mechanism of High-Nickel Cathode Depending on Discharge Rates and Charge Voltages during Long-Term Cycling Article 10.1021/acs.nanolett.5c00994 1 Nano Letters, v.25, no.16, pp.6735 - 6742 Nano Letters 25 16 6735 6742 N scie scopus 001466599300001 2-s2.0-105003611200 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article NI-RICH LITHIUM OXIDE TRANSITION-METAL degradationmechanism STEM-EELS lithium-ion batteries high-Ni cathode materials cation mixing