Clean and green supercapacitors for energy efficiency and transport applications
Capacitors have been an integral part of electrical circuit boards for years. Technical advances have resulted in increases in capacitance on the order of thousands. With expanded energy storage, supercapacitors or ultracapacitors are powerful enough to take on energy storage in hybrid and electric vehicles or intermittent renewable energy technologies. The EU-funded ENERGY CAPS (Development of a sustainable and safe hybrid supercapacitor with high specific energy and maintained high specific power and cyclability) project aimed to address some of the current challenges associated with hybrid supercapacitors. Work began with the development of individual cell components such as new electrodes, a high-performance polymer separator and an optimised electrolyte mixture. The focus was on reduced environmental impact and low cost. These components were then integrated into lab-scale prototypes that were tested and optimised before delivery of the final prototype. Project partners continuously evaluated the recyclability of the device components, and successfully assessed the environmental impact of manufacturing and recycling processes. They devised a process that fulfils the obligations and 50 % recycling efficiency requirements put forth by the EU's Batteries Directive. Through secondments and recruitments, researchers developed a sustainable and safe hybrid supercapacitor. It features high specific energy, maintained high specific power and long cycle life for energy efficiency and transport applications, primarily plug-in hybrids, electric cars and smart grids. The lithium-ion capacitors offer several benefits. They provide energy, power, safety and lifetime advantages that outperform existing technologies. The limited heat generation achieved cannot be duplicated by other systems, which favours hybrid vehicles. When compared to lithium batteries, lower heat production enables the use of simpler, cheaper and more reliable cooling systems. Acceleration can be maintained up to 10 times longer than current supercapacitors thanks to higher energy density. ENERGY CAPS has important implications for renewable energy storage and green transport. It will also have important impact on the EU's ambitious environmental goals, contributing to the societal challenges laid down in Europe 2020.
Keywords
Supercapacitors, ultracapacitors, ENERGY CAPS
