Effects of Graphite Heat-Treatment Temperature on Single-Crystal Li[Ni5Mn3Co2]O2/ Graphite Pouch Cells
Que Huang, Stephen L. Glazier, A. J. Louli, Mark McArthur, Changcheng Liu, Jeremy Schrooten and J. R. Dahn (2020).
Journal of The Electrochemical Society 167(8). https://doi.org/10.1149/1945-7111/ab9381
Abstract
In this work, the effect of the heat-treatment temperature of synthetic (artificial) graphite on the electrochemical performance of LiNi0.5Mn0.3Co0.2O2/graphite pouch cells was explored and compared with cells utilizing commercial-grade artificial and natural graphite materials. Two optimized electrolyte additive blends, 2% VC + 1% DTD and 1% LiPO2F2, were used in the cells tested. Physical properties of the different graphite electrodes, such as morphology, pore-size, crystallinity and thermal stability were investigated. Then, cells with each graphite material were tested with a variety of electrochemical techniques: ultra-high precision coulometry, long-term cycling, high-rate cycling, isothermal microcalorimetry, operando pressure tests and open circuit storage tests. Marginal benefits were found in electrochemical tests for cells with graphite materials that had been heat-treated to lower temperatures. However, in all tests, cells with synthetic graphite had superior performance compared to natural graphite.
