US Patent 7972725 Polyimide electrode binders

Irreversible first cycle capacity loss in lithium secondary cells having a cell electrode based on a powdered material and a binder may be significantly decreased or eliminated by using an aliphatic or cycloaliphatic polyimide binder. Compared to conventional polyimide binders prepared by reacting an aromatic dianhydride and a diamine, the disclosed polyimide binders have decreased aromatic carbonyl content, may be less likely to undergo electrochemical reduction, and may be less likely to consume electrons that might otherwise help lithiate the electrode.