a regenerative fuel cell or reverse fuel cell (rfc) is a fuel cell run in reverse mode, which consumes electricity and chemical b to produce chemical a. by definition, the process of any fuel cell could be reversed.  however, a given device is usually optimized for operating in one mode and may not be built in such a way that it can be operated backwards. standard fuel cells operated backwards generally do not make very efficient systems unless they are purpose-built to do so as with high-pressure electrolysers, regenerative fuel cells, solid-oxide electrolyser cells and unitized regenerative fuel cells. ==process description== a hydrogen fueled proton exchange membrane fuel cell, for example, uses hydrogen gas (h2) and oxygen (o2) to produce electricity and water (h2o); a regenerative hydrogen fuel cell uses electricity and water to produce hydrogen and oxygen. when the fuel cell is operated in regenerative mode, the anode for the electricity production mode(fuel cell mode) becomes the cathode in the hydrogen generation mode(reverse fuel cell mode), and vice versa. when an external voltage is applied, water at the cathode side will undergo electrolysis to form hydrogen and oxide ions; oxide ions will be transported through the electrolyte to anode where it can be oxidized to form oxygen. in this reverse mode, the polarity of the cell is opposite to that for the fuel cell mode. the following reactions describe the chemical process in the hydrogen generation mode: at cathode: h2o + 2e- â h2 + o2- at anode: o2- â 1/2o2 + 2e- overall: h2o â 1/2o2 + h2 ==solid oxide regenerative fuel cell (sorfc)== one example of rfc is solid oxide regenerative fuel cell. solid oxide fuel cell operates at high temperatures with high fuel to electricity
Fuel_cells