In this work, we use a computational model, the E-b(ER) model, and the molecular orbital theory to investigate the relationship between the molecular structures and the stabilities of three redox shuttle electrolyte additives for overcharge protection in Li ion cells: unstable 1,4-dimethoxybenzene (DMB), unstable 2,3,5,6-tetrafluoro-1,4-di-tertbytoxybenzene (TFDTB) and stable 2,5-di-tertbutyl-1,4-dimethoxybenzene (DTDMB). We propose a pathway for the proton elimination and polymerization reactions of the DMB cations, the dimerization-assistant proton elimination and polymerization reactions, and also discuss the connection of the E-b(ER) model with the chemical/electrochemical reactions, in which the redox shuttle cations are involved in Li ion cells. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.007302jes] All rights reserved.