Overcharge protection of lithium-ion batteries with phenothiazine redox shuttles

Overcharge in lithium-ion batteries (LIBs) can be mitigated using electron-donating small molecules with oxidation potentials just above the end-of-charge potential of the electrochemical cell. These additives function by oxidizing at the cathode/electrolyte interface, forming radical cations, and are then reduced at the anode/electrolyte interface, becoming neutral again. A variety of redox shuttles have been reported since 2005 including derivatives of TEMPO, alkoxybenzene, and phenothiazine. This perspective focuses on phenothiazines redox shuttles and their performance in LIBs. Overcharge protection of Li-ion batteries with a variety of phenothiazine derivatives.