Nowadays Li-ion batteries use mainly inorganic compounds as electrode materials especially transition metal based ones. Although their performances are satisfying, they present several important drawbacks. Indeed these compounds are expensive and leads to large environmental footprint because they are prepared due to energy-consuming techniques from rare mineral precursors. Moreover, this technology is based on the use of lithium leading to geostrategic issues.
Some organic redox compounds such as viologen based derivatives can reversibly react with anions. Consequently they appear as an interesting alternative to conventional active materials especially for negative electrode for battery in anion-ion configuration which not use metallic counter ions. Interestingly these organic molecules can be easily prepared using simple organic chemistry techniques from low cost precursors. However their redox potential is too high (~2-2.5V vs Li+/Li) for the development of high energy density batteries.
The work of this thesis will firstly focus on the synthesis of new insoluble structure based on viologen derivatives presenting a redox potential below 2V vs Li+/Li. Some fine characterizations in particular Electron Paramagnetic Resonance (EPR) will be applied in order to better understand their electrochemical mechanisms.