Energy harvesting from CO2 emission exploiting ionic liquid-based CAPacitive mixing

ongoing

When two solutions with different composition are mixed, free energy of mixing is released. This phenomenon was deeply investigated in the last decades in order to harvest the so-called salinity gradient power. One of the most incipient technology that allows to harvest this energy is the Capacitive Mixing (CapMix) and its working mechanism is based on a fluidic electrochemical cell, similar to a supercapacitor. Since this mixing phenomenon holds true for both liquids and gases, my idea is to harvest energy from anthropic CO2. The energy density stored in the CO2 emission is tremendously higher than that stored in salinity gradient and theoretically estimated as high as 1570 TWh/year. Since ions are needed in CapMix process, with CO2CAP I propose for the first time to exploit a green ionic liquid (IL), i.e. a bio-derived molten salt at room temperature, both as electrolyte and CO2 absorbing medium in a CapMix cell. The principle consists of flowing a concentrated CO2 gas stream, alternated to vacuum step, in the IL during the charging/discharging of two electrodes. The CO2 will induce an electric double layer (EDL) expansion of charges at the electrode/IL interface thereby converting the released mixing energy into electrical energy. To reach this goal, the objectives of CO2CAP are to develop novel cutting-edge carbon-based electrodes and amino acid-based IL designed to maximize the EDL of charges at the electrode/IL interface, enhancing at the same time the CO2 absorption capacity. This will be possible by using a multidisciplinary approach based on materials engineering, modelling, advanced characterization methods and novel architecture of the electrodes. The engineered materials and cell will allow to demonstrate the feasibility of this new electrochemical approach, enabling a deeper understanding of the physical and electrochemical phenomena occurring in such a complicated system, and paving the way to a new generation of CO2-free renewable energy source.