Supercapacitors, especially hybrid supercapacitors, are a very promising technology for application in plug-in hybrids, electric cars or the smart grid, which presents a number of interesting advantages over batteries with regard to specific power and cycle life. However, a number of research challenges remain.The Energy Caps project aims at developing a sustainable and safe hybrid supercapacitor with high specific energy and maintained high specific power and cyclability. For this purpose, five partners from two SMEs, one large company and two universities, located in four different European countries, will mutually second personnel to exchange their complementary knowledge. The research programme will involve the development of new electrodes, a high performance polymer separator and an optimized electrolyte mixture. Subsequently, these components will be combined, first in a lab cell and then in a larger prototype. The future recyclability of the novel components will be assessed throughout the project and towards the end the environmental impact of manufacturing and recycling process will be assessed.The project will combine academic knowledge about the novel hybrid supercapacitor concept, modelling and the mechanistic understanding of supercapacitors with industrial expertise in the area of material sciences, prototyping and industrial application of supercapacitors and recycling.The project has a balanced mixture of secondments (21 researchers, 142 month) and recruitments (4 researchers, 96 month). The secondment schedule was set-up to match the work plan and the transfer of knowledge will be supported by workshops between the partners involved in the project. Collectively, the consortium has the appropriate combination of expertise and equipment to execute the project.The project will initiate a long-lasting collaboration between the partners and will result in a commercially exploitable supercapacitor concept.