3,7-Bis(trifluoromethyl)-N-ethylphenothiazine: a redox shuttle with extensive overcharge protection in lithium-ion batteries

3,7-Bis(trifluoromethyl)-N-ethylphenothiazine (BCF3EPT) was evaluated as a redox shuttle for overcharge protection in lithium-ion batteries. Constant-charging experiments were performed to compare the compound to 1,4-di-tert-butyl-2,5-dimethoxybenzene and N-ethylphenothiazine. BCF3EPT showed significantly longer overcharge protection when compared to either benchmark at the same concentrations in LiFePO4/graphite batteries.