Carbon in the form of carbonate ions

In the fuel cell, the carbon dioxide that is formed at the anode is recycled back to the cathode. Although very promising, there are still problems with materials and the containment of the electrolyte. 

The potential for this reaction to occur is 0.9 V which corresponded very closely to the extrapolation of the linear portion of the measured cell potential to zero current. This approach has several advantages over other methods of generating carbon monoxide and oxygen from carbon dioxide, in that no precious metals are required, pure carbon monoxide is produced, which could be stored and converted into other chemicals, and the process can operate at the carbon dioxide pressures found in flue gases. 

This has two effects as it deposits carbon on the cathodic product which may cause contamination and, secondly, the newly created oxygen ions can diffuse to the anode where fresh carbonate ions can be created  

The substitution of the carbon anode by an inert anode, such as CaTi Rui 03, obviously avoids the carbon problem and raises the quality of the metallic product. It was also found that the polarisation, at a given current density, on an inert anode was far lower than that on a carbon anode so that the loss of the fuel cell effect was offset by the difference in polarisation (S. Jiao and D.J. Fray, unpublished data). 

Lithium carbonate is the cheapest precursor for the production of lithium, which is predicted to play a major part in energy storage, but the only production route for lithium is by the electrolysis of lithium chloride. It would be an advantage if lithium carbonate could be electrolysed directly but electrochemical reaction of the carbonate ion is always more favourable than the deposition of lithium, assuming the melt is saturated with lithium oxide  

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