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Presenter: Jing Ying Ko Abstract<\/strong><\/p>\n\n\n\n To fulfill the demand of long driving range for electric\nvehicles without compromising the weight and cost of battery is to increase its\nenergy density, i.e. by extending its voltage window. In this work, we intend\nto examine the aging phenomena under high-voltage operation of a NMC\/graphite\ncell.<\/p>\n\n\n\n When cycled up to 4.5 V, a rapid performance degradation\nis observed. Aging stems from the NMC electrode rather than graphite. The\nsevere NMC impedance rise causes an inaccessibility of utilizing its capacity,\nthus inducing cell failure. Therefore, an extended physics-based impedance\nmodel is developed to fit electrochemical impedance spectroscopy data from NMC\nsymmetric cells. <\/p>\n\n\n\n The model indicates the particle surface layer, an\nelectrode layer near separator and current collector resistance as the main\ncauses of impedance rise. Higher temperature enhances the rate of degradation.\nExperimental evidences from scanning electron microscopy and Raman spectroscopy\nsupport these model findings.<\/p>\n\n\n\n Full conference program<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
Title: Model and experimental studies: Understanding aging mechanisms under high-voltage operation
Affiliation: KTH Royal Institute of Technology<\/em><\/p>\n\n\n\n