The University of Kentucky presented its research on using electrolyte additives called redox shuttles to protect batteries from overcharging. The research was presented at a meeting of the American Chemical Society as part of the 245th National Meeting & Exposition of the American Chemical Society. The abstract of the redox presentation follows.
Increasing redox shuttle oxidation potentials to match high voltage cathodes in lithium-ion batteries
Susan Odom, University of Kentucky
Phone: 859-257-3294
Email: susan.odom@uky.edu
Electrolyte additives called redox shuttles can protect batteries in series from experiencing overcharge, a condition in which one or more fully charged cells continue to receive applied current. Derivatives based on 1,4-dimethoxybenzene, N-alkylphenothiazine, and TEMPO cores have been reported as superior additives for overcharge protection. Eventually these electrolyte additives fail, presumably due to decomposition of their radical cation forms. Increased electron deficiency makes radical cations more susceptible to nucleophilic attack, which may result in reactions with electrolyte components. Few examples of stable redox shuttles for high voltage cathodes have been reported, presumably due to their high reactivity. Our work focuses on improving the stability of redox shuttles for high voltage cathodes. We have synthesized a variety of carbazole, diphenylamine, phenothiazine, and phenoxazine derivatives containing electron-withdrawing groups. This study focuses on the electrochemical analysis of the new derivatives and the stability of their radical cation forms.
Increasing redox shuttle oxidation potentials to match high voltage cathodes in lithium-ion batteries
Susan Odom, University of Kentucky
Phone: 859-257-3294
Email: susan.odom@uky.edu
Electrolyte additives called redox shuttles can protect batteries in series from experiencing overcharge, a condition in which one or more fully charged cells continue to receive applied current. Derivatives based on 1,4-dimethoxybenzene, N-alkylphenothiazine, and TEMPO cores have been reported as superior additives for overcharge protection. Eventually these electrolyte additives fail, presumably due to decomposition of their radical cation forms. Increased electron deficiency makes radical cations more susceptible to nucleophilic attack, which may result in reactions with electrolyte components. Few examples of stable redox shuttles for high voltage cathodes have been reported, presumably due to their high reactivity. Our work focuses on improving the stability of redox shuttles for high voltage cathodes. We have synthesized a variety of carbazole, diphenylamine, phenothiazine, and phenoxazine derivatives containing electron-withdrawing groups. This study focuses on the electrochemical analysis of the new derivatives and the stability of their radical cation forms.
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