Solid-State Poly(ionic liquid) Gels for Simultaneous CO2 Adsorption and Electrochemical Reduction

Abstract

Managing carbon dioxide (CO2) released from large-scale industrial processes is of great importance, yet there remain significant technical challenges. Herein, the fabrication of 1-mm-thick solid-state electrochemical devices based on poly(ionic liquid) ionogels with embedded electrodes capable of both adsorption and electrochemical reduction of CO2 is reported. The ionogels are prepared via radical polymerization and chemical crosslinking of a vinyl imidazolium trifluoromethanesulfonimide ionic liquid monomer in the presence of additional ionic liquids (ILs) that act as swelling agents and enhance ionic conductivity. The effects of the ILs concentration and the degree of crosslinking on the mechanical properties, conductivity, and CO2 adsorption of the ionogels are investigated. The ionogels are shown to have ionic conductivities as high as 0.6 mS cm−1. The results of quartz crystal microbalance analyses demonstrates that the CO2 adsorption of the ionogels reaches up to ≈22 mg g−1, which is 10-fold higher than that of their native ionic liquid. Moreover, the ionogels are easily recoverable after CO2 adsorption. The flexibility, conductivity, and CO2 capture capacity of this system can be controlled by the crosslinking ratio and ionic liquid content of the ionogels. This electrochemical device has the potential to be used in large scale plants for capturing CO2 for further electrochemical reactions.