Smart Electrolytes for a New Perspective on Electrochemical Energy Storage

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Electrochemical energy storage systems are crucially important in developing the technologies required to ensure the sustainable development of our modern society. Certain electrochemical energy storage devices, such as lithium-ion batteries and supercapacitors, are widely applied and have already changed the way we store electricity, mainly in nomad electronic devices and electric vehicles. To date, the properties and performance of these devices have been largely defined by the electroactive material of which the electrodes are composed. Consequently, there is a considerable gap between the development rate of active materials, and that of the electrolytes used to support ionic charge transfer within the cell. The proposed research program is part of my group's ongoing effort to change this situation by developing advanced electrolytes that play an active role in the reactions leading to energy storage. The objective of this proposed research is to increase the energy density of redox-active electrolyte supercapacitors and develop new, metal-free liquid electrode batteries using redox ionic liquid electrolytes. This objective is motivated by the fact that ion transport is generally 103 faster in liquid than in solid phases, leading to improved electrochemical reaction kinetics. Smart electrolytes, such as the ones I intend to develop through this program, are not obtained solely by adding chemical functionality to a conventional electrolyte; rather, they feature specific molecules which combine the roles of solvent, ionic carrier, and active charge storage centre. Ionic liquids are highly suitable platforms for smart electrolyte development, given that there are very few ways to chemically modify traditional solvent molecules and maintain a liquid phase. These redox ionic liquids contain electroactive groups linked to their ions; when oxidized or reduced, these groups are capable of storing charges. In particular, their energy density remains limited in comparison to solid active materials, despite their high concentration of redox centres (i.e. one per ion) which renders them particularly interesting for energy storage. In addition, their development is being slowed by a lack of fundamental knowledge of molecular structure upon electron transfer, as well as on the interactions occurring at the electrode interface. My research program will address these issues through three objectives: increasing energy density through the use of multiple electron transfer reactions, understanding the relationship between ion size and nature on insertion in nanoporous carbon materials, and precisely evaluating the performance of redox ionic liquid in energy storage devices of different configurations. My research program may potentially impact numerous sectors of critical importance to Canada, specifically by generating new and foundational knowledge, and training highly-qualified personnel (HQP) in the fields of energy storage and materials.