Abstract: After undergoing overcharge abuse, non-aqueous rechargeable lithium batteries can be left in a relatively hazardous state of charge, representing a safety concern with respect to subsequent thermal or mechanical abuse. Electrolyte additives which electrochemically form conductive polymers can be used to create a short circuit inside the battery as a result of overcharge abuse and automatically discharge the battery internally. The invention is particularly suitable for batteries equipped with electrical disconnect devices which cannot be discharged externally after the disconnect has activated. Aromatic compounds such as biphenyl are particularly suitable additives.

Abstract: Greater energy densities can be obtained in aqueous rechargeable batteries based on the `rocking chair` principle by the use of certain polymer insertion compounds as an electrode material. Aqueous lithium ion batteries using poly(carbon disulfide) polymer as an anode have energy densities comparable to nickel metal hydride batteries.