High potential quinones for battery applications
Title: High potential quinones for battery applications
DNr: SNIC 2015/1-62
Project Type: SNIC Medium Compute
Principal Investigator: Martin Sjödin <Martin.Sjodin@angstrom.uu.se>
Affiliation: Uppsala universitet
Duration: 2015-02-27 – 2016-03-01
Classification: 10402 10405 20499
Keywords:

Abstract

The purpose of this research proposal is to use first-principles calculations to design novel materials for application in rechargeable batteries. The specific aims are: (i) To achieve fundamental understanding on how charge trapping by binding of the counter ion in the vicinity of the redox active group influences the reduction potential (ii) To develop a new first-principles high-throughput screening system to establish trends in counter ion binding sites (iii) To investigate the influence of solvent and electrolyte ions on the reduction potential of the systems above. The development of organic matter based electrical energy storage systems are currently hampered by the poor conductivities of organic matter as well as by the solubility of most small organic molecules in common battery electrolytes. As experimental capacities of organic matter based electrode materials have been found that are comparable to, and even succeeds, conventional cathode material capacities for LIBs (1,2) resolution of these issues may provide the society with technologically competent alternatives based on renewable and readily accessible resources. The adopted strategy in our research group to overcome both conductivity- and dissolution-problem is to attach high capacity redox active pendant groups (PG) on a conducting polymer (CP) backbone forming a conducting redox polymer (CRP). The PG group serves as capacity carrying component while the CP backbone renders the material conducting and ensures low material solubility. Combination of CP-backbones with PGs requires redox matching between the two components as the CP is only conducting in its reduced and oxidized states and hence the pendant group redox chemistry must occur in potential regions where the polymer is charged. We focus on the development of high potential, quinone based materials. In the non-polar environment, charged species are high in energy. It would therefore be possible to increase the energy of the oxidized state if the positive charge induced by oxidation is trapped in the materiel. By employing first-principles theory based on density functional theory (DFT), we will investigate how the nature of the ion trap (T) affects the redox potential of the quinone and how solvent polarity and the nature of the electrolyte salt affects the redox properties by computational means. The redox potentials in solution will be calculated by combining DFT and self-consistent reaction field methods where the free energies (including all internal energy and entropic contribution) are calculated using the Born–Haber thermodynamic cycle. The explicit solvent effect will be assessed by carrying out ab-initio molecular dynamics (MD) simulations. A sequential MD/DFT scheme will be used to determine the electronic structure at a given temperature. In this approach, snapshots of the MD simulations are selected to carry out high-accurate single point DFT calculations, and subsequently, the obtained electronic structures are averaged. We will explore the Born-Oppenheimer molecular dynamics as implemented in the Vienna Ab-initio Simulation Package (VASP). 1. Chen et.al. ChemSusChem, 2008, 1, 348-355. 2. Renault, et.al. ChemSusChem, 2014, 7, 2859-2867.