First-principles study of eletronic properties of radical polymers for organic battery applications

Abstract

Nowadays, there is an increasing demand for suitable energy storage devices to power the electronic devices used in a society continually oriented to technology and mobility. In order to solve this problem, and allied to environmental concerns, organic radical batteries (ORB) have been considered as possible solution by the electronic industry. In these devices, the electrodes consist on a moiety of a radical polymer and a conductive additive, with well defined electrochemically properties, which gives to ORB interesting performances, like short charging times and stable voltages, with the bonus of good device processability using wet techniques, opening the possibility to build thin and flexible batteries. The suitable electrochemical properties of radical polymers for battery applications arises from the fact that they present an organic radical pendant group with a nitroxide radical which may easily undergo reversible oxidation, forming an oxoammonium cation, or reversible reduction, forming an aminoxyl anion [1] . By suitable molecular design of the pendant group it’s possible to optimize the eletrochemical properties of the radical polymer [2], and thus of the electrodes, with the perspective to built an all-ORB. In this communication we will present some of our recent results, obtained by density functional theory (DFT) calculations, in studying the effect of the molecular structure of the pendant group and polymer backbone on the electronic structure and related properties of radical polymers used in ORB. The results obtained can be used as input parameters in mesoscopic models to study the process of charge/discharge of ORB.

[1] K. Oyaizu,H. Nishide. Adv. Mater., 21, 2339-2344 (2009). [2] T. Janoschka, M. D. Hager,U. S. Schubert. Adv. Mater., 24, 6397-6409 (2012).