Extending the high-voltage operation of Graphite/NCM811 cells by constructing a robust electrode/electrolyte interphase layer

Autor: Wengao Zhao, Kuan Wang, Romain Dubey, Fucheng Ren, Enzo Brack, Maximilian Becker, Rabeb Grissa, Lukas Seidl, Francesco Pagani, Konstantin Egorov, Kostiantyn V. Kravchyk, Maksym V. Kovalenko, Pengfei Yan, Yong Yang, Corsin Battaglia
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Materials Today. Energy, 34
Materials Today Energy, 34, Art.-Nr.: 101301
ISSN: 2468-6069
DOI: 10.3929/ethz-b-000610196
Popis: The cycling life of layered Ni-rich LiNi1-x-yCoxMnyO2 (NCM, 1-x-y ≥ 0.8) is typically extended by restricting the upper cut-off voltage during cycling to below 4.2 V, sacrificing, however, the untapped additional capacity above the cut-off voltage. To make this additional capacity available, we investigate graphite/LiNi0·8Co0·1Mn0·1O2 cells cycled to high upper cut-off voltages up to 4.5 V at high electrode areal capacities of 4.8 mAh/cm2 in a standard electrolyte consisting of 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate and ethylene methyl carbonate (ethylene carbonate:ethylene methyl carbonate = 3:7 vol% + 2% vinylene carbonate). Although the initial capacity reaches 190 mAh/g, the capacity retention after 300 cycles to 4.5 V is only 66%. Employing a combination of tris(trimethylsilyl)phosphite and lithium difluoro(oxalato)borate as electrolyte additives, we demonstrate excellent capacity retention of 85% after 300 cycles to 4.5 V. Moreover, graphite/LiNi0·8Co0·1Mn0·1O2 cells with additives show improved capacity retention also at elevated temperatures of 60 °C. A detailed post-mortem analysis reveals the formation of a compact and LiF-rich and B-containing cathode/electrolyte interphase layer on the LiNi0·8Co0·1Mn0·1O2 particles cycled with tris(trimethylsilyl)phosphite and lithium difluoro(oxalato)borate additives, substantially suppressing the transition metal dissolution and the cation-disordered layer formation on the exposed particles' surface.
Materials Today Energy, 34
Databáze: OpenAIRE
Externí odkaz: