PEDOT: PSS as a Functional Binder for Cathodes in Lithium Ion Batteries

Abstract

The application areas of Li-ion batteries continue to grow, hence improvement in their energy d., rate capability and cycle life is necessary. A typical cathode contains usually redox active transition metal oxides as active materials, conductive additives to ensure electronic cond. and binder supporting matrix. In this work we report the behavior and properties of carbon black-free LiFePO4 composite electrode, where poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) is accomplishing a dual role of binder and conducting additive. The effect of the polymer amt. on the morphometric properties of the electrodes was studied using SEM, mercury porosimetry and high resoln. x-ray computed tomog. The electrochem. performance and the cycling stability of the composite electrodes were compared to the behavior of conventional cathodes with carbon additives and poly(vinylidene fluoride) binder. With increasing PEDOT:PSS content a decrease in the overvoltage and correspondingly an improvement in the rate capability is obsd. Composite cathodes contg. 8% PEDOT:PSS show comparable electrode capacity and better cyclic stability than conventional composite cathode. [on SciFinder(R)]