Capacitors are ubiquitous in any electronic device, with aluminium and tantalum electrolytic capacitors used whenever larger capacitances are required. However, they suffer from reliability issues, especially when operating at high temperatures: a temperature increase of 10 ºC halves their life. In the case of tantalum there is an additional concern: it is considered a critical raw material that generates environmental and societal concerns and it has been gaining a lot of attention from capacitor manufacturers in the search for an alternative technology solution. P.CAP project brings an alternative to aluminium and tantalum electrolytic capacitors: planar electric double layer capacitors (P.EDLCs) with enhanced performance at mid frequencies and high temperature. EDLCs are energy storage devices with a much larger DC capacitance than capacitors and excellent cyclability, but current technology behave as resistors at frequencies greater than 1 Hz. Under the right conditions, we have proven that they can operate at higher frequencies (1-200 Hz) while maintaining the merits of EDLCs: large capacitance and extended lifetime. Moreover, when thermally stable ionic liquids are used as electrolyte, they can operate at temperatures above 200 ºC. In the P.CAP project, a TRL7 prototype bipolar capacitor that can operate at >250 ºC, with an operating life of more than 1000 h at this temperature and a rated voltage above 40 V, will be manufactured. This prototype will be used as a minimum viable product to validate the device in applications where reliability and high-temperature are required, such as mining and electric vehicles.