Improved Electrochemical Capacitor Performance through Modeling, Chemical Modification and Electrode Design

Electrochemical capacitors (ECs) are energy storage systems used for short high-intensity power bursts, e.g. airbag deployment, and fill a critical performance gap between batteries and capacitors. This research program capitalizes on our expertise in electrochemistry, pores, carbon and manganese oxide to: understand charge transport mechanisms that slow EC response and waste energy; identify key reactions that hinder charge storage; and develop materials that maintain high power but need less frequent recharging. Success in this program will lead to new EC diagnostics/models, better-designed materials and improved performance in consumer devices ranging from life-saving pacemakers to electric vehicles. Theme 1 explores how charge movement through electrodes relates to EC performance (energy, power, efficiency). Guided by data from real electrodes, we use computer simulation and hardware circuits to help us visualize charge movement in a system, which is not possible in a real electrode. This allows us to design higher-power materials and explain important EC behaviours. The new designs are then translated into real electrodes with improved structure and performance, such as those in Theme 3. Theme 2 focuses on identifying parasitic chemical and physical processes that can steal charge or damage an EC. For many common and emerging EC materials (carbon, metal oxides, polymers) the research into these processes is in its infancy, in part due to a lack of effective diagnostics. Using our almost two decades of expertise in developing much-needed diagnostics and identifying key EC reactions, we mitigate these parasitic reactions, resulting in less energy-waste, longer shelf-life and fewer EC replacements. Theme 3 addresses a key barrier to widespread EC use; despite their excellent power performance, their energy is low, necessitating frequent recharging. Our novel electrode architectures position high energy materials on selected portions of high-power electrodes, preserving the benefits of both. Computer modelling will model optimal positioning for these materials. Chemical and electrochemical synthesis will translate these architectures into real electrodes for EC implementation. The success of these innovative electrode designs will be transformative, giving tunable control over EC power and energy; tuning an EC to match the precise device requirements means less waste of materials (improved environmental sustainability), lower volume/weight in consumer devices and a wider range of potential applications. As a top 10 world producer of many EC materials, Canada will benefit from improved EC performance leading to a broader use of ECs in commercial devices. This program will provide our growing energy sector with access to much needed highly skilled personnel who understand the fundamental science of technologically important materials and who have a unique skill-set that combines both modelling and in-lab testing of EC materials.