TY - JOUR
T1 - A Comprehensive Understanding of the Aging Effects of Extreme Fast Charging on High Ni NMC Cathode
AU - Tanim, Tanvir
AU - Yang, Zhenzhen
AU - Finegan, Donal
AU - Chinnam, Parameswara
AU - Lin, Yulin
AU - Weddle, Peter
AU - Bloom, Ira
AU - Colclasure, Andrew
AU - Dufek, Eric
AU - Wen, Jianguo
AU - Tsai, Yifen
AU - Evans, Michael
AU - Smith, Kandler
AU - Allen, Jeffery
AU - Dickerson, Charles
AU - Quinn, Alexander
AU - Dunlop, Alison
AU - Trask, Stephen
AU - Jansen, Andrew
N1 - Publisher Copyright:
© 2022 Wiley-VCH GmbH.
PY - 2022
Y1 - 2022
N2 - Extreme fast charging (XFC, =10-15 min charging) is expected to increase the adoption of electric vehicles (EVs), but currently accelerates degradation in Li ion cells. As the battery industry shifts toward high Ni content cathodes, such as LiNi0.8Mn0.1Co0.1O2 [NMC811] -- due to its higher specific capacity, better transport properties, and lower Co content -- a complete understanding of the degradation mechanisms of NMC811 under XFC conditions, and how those compare to lower Ni content cathodes, like LiNi0.5Mn0.3Co0.2O2 [NMC532], is needed. Such comprehensive understanding would identify the most critical materials gaps that need to be addressed for enabling XFC long-life cells for EVs. Using well-defined cells and charging protocols, this study maps out the key aging mechanisms for NMC811 cycled at different XFC conditions [at 1C-9C to 4.1V (~100% state-of-charge [SOC]) and at 9C to 3.63V (~35% SOC), 3.77V (~60% SOC), and 3.94V (~80% SOC)] for up to 1000 cycles. To acquire a fundamental understanding of utilization and degradation, cells were evaluated using a range of electrochemical techniques, and a suite of multimodal and multiscale microscopy techniques to quantify chemical, structural, and crystallographic degradation as a function of cycling conditions for the NMC cathode. When comparing NMC532 to NMC811, it is observed that NMC811 has a greater subsurface crystallographic degradation from layered to rock salt structures and displays a similar magnitude of sub particle cracking. However, the NMC811 maintains superior performance despite those advanced degradations. The superior cycle life performance is attributed to the NMC811 particles having radially oriented grains and improved transport properties. NMC811 showed between 4.6× to 3.15× reduction in capacity fade than NMC532 for charging rates between 4C (e.g., 15-minute charging) and 6C (10-minute charging).
AB - Extreme fast charging (XFC, =10-15 min charging) is expected to increase the adoption of electric vehicles (EVs), but currently accelerates degradation in Li ion cells. As the battery industry shifts toward high Ni content cathodes, such as LiNi0.8Mn0.1Co0.1O2 [NMC811] -- due to its higher specific capacity, better transport properties, and lower Co content -- a complete understanding of the degradation mechanisms of NMC811 under XFC conditions, and how those compare to lower Ni content cathodes, like LiNi0.5Mn0.3Co0.2O2 [NMC532], is needed. Such comprehensive understanding would identify the most critical materials gaps that need to be addressed for enabling XFC long-life cells for EVs. Using well-defined cells and charging protocols, this study maps out the key aging mechanisms for NMC811 cycled at different XFC conditions [at 1C-9C to 4.1V (~100% state-of-charge [SOC]) and at 9C to 3.63V (~35% SOC), 3.77V (~60% SOC), and 3.94V (~80% SOC)] for up to 1000 cycles. To acquire a fundamental understanding of utilization and degradation, cells were evaluated using a range of electrochemical techniques, and a suite of multimodal and multiscale microscopy techniques to quantify chemical, structural, and crystallographic degradation as a function of cycling conditions for the NMC cathode. When comparing NMC532 to NMC811, it is observed that NMC811 has a greater subsurface crystallographic degradation from layered to rock salt structures and displays a similar magnitude of sub particle cracking. However, the NMC811 maintains superior performance despite those advanced degradations. The superior cycle life performance is attributed to the NMC811 particles having radially oriented grains and improved transport properties. NMC811 showed between 4.6× to 3.15× reduction in capacity fade than NMC532 for charging rates between 4C (e.g., 15-minute charging) and 6C (10-minute charging).
KW - cathode degradation
KW - extreme fast charging
KW - lithium-ion batteries
UR - http://www.scopus.com/inward/record.url?scp=85128790623&partnerID=8YFLogxK
U2 - 10.1002/aenm.202103712
DO - 10.1002/aenm.202103712
M3 - Article
AN - SCOPUS:85128790623
SN - 1614-6832
VL - 12
JO - Advanced Energy Materials
JF - Advanced Energy Materials
IS - 22
M1 - 2103712
ER -