Carbon dioxide recovery system and working electrode
Provided is an electrochemical cell comprising a working electrode and a counter electrode. The working electrode comprises an electrode base material, a CO 2 adsorbent, and a binder. Application of a voltage between the working electrode and the counter electrode causes electrons to be supplied from the counter electrode to the working electrode, and enables the CO 2 adsorbent to bind to CO 2 as electrons are supplied. The binder has electrical conductivity, and the CO 2 adsorbent is held in the electrode base material by the binder.
1 . A carbon dioxide recovery system that separates CO 2 from a CO 2 -containing gas, by an electrochemical reaction, comprising:
an electrochemical cell comprising a working electrode and a counter electrode;
wherein the working electrode comprises an electrode base material, a CO 2 adsorbent, and a binder,
application of a voltage between the working electrode and the counter electrode causes electrons to be supplied from the counter electrode to the working electrode, and enables the CO 2 adsorbent to bind CO 2 thereto as electrons are supplied,
the binder comprises an ionomer made of a polymer electrolyte, and the CO 2 adsorbent is held in the electrode base material by forming a mixture with the binder comprising the ionomer,
the electrochemical cell further comprises an insulating layer and an ion conductive member having ionic conductivity,
the insulating layer is provided between the working electrode and the counter electrode and is configured to separate the electrodes from each other,
the ion conductive member is provided between the working electrode and the counter electrode via the insulating layer, is configured to be in direct contact with the electrode base material, and contacts the CO 2 adsorbent inside the electrode base material,
the electrode base material is a porous material,
the binder is configured to enter and become fixed to voids of irregularities formed in the electrode base material to generate a mechanical binding force with the electrode base material,
the CO 2 -containing gas contains a plurality of gases other than CO 2 , and
the binder is configured to have CO 2 -selective permeability, in which gases other than CO 2 are unable to permeate the binder to enable CO 2 to be selectively permeated.
2 . The carbon dioxide recovery system according to claim 1 , wherein the binder has hydrophobicity.
3 . The carbon dioxide recovery system according to claim 1 , wherein the binder and the CO 2 adsorbent form a mixture, and the mixture is held in the electrode base material.
4 . The carbon dioxide recovery system according to claim 1 , wherein the ion conductive member is a gel-state material or solid-state material.
5 . The carbon dioxide recovery system according to claim 1 , wherein the binder is a solid-state material or a gel-state material containing the CO 2 adsorbent and an organic solvent in a dispersed and mixed state, with a raw material of the binder, a liquid substance with fluidity, solidified or subjected to gelation in a state of entering voids of irregularities formed in the electrode base material.
6 . The carbon dioxide recovery system according to claim 1 , wherein moisture is present in the CO 2 -containing gas, which moisture is unable to permeate the binder to enable CO 2 to be selectively permeated.
7 . The carbon dioxide recovery system according to claim 1 , wherein the plurality of gases other than CO 2 includes at least one of N 2 and O 2 .