Regenerative fuel cells storage

Clearly, the CRR is a far more reversible reaction than ORR and the performance is excellent (0.5 W/cm ). In fact, the exchange current density of CRR and HOR (Vilekar et al., 2010) are of a similar order. Consequently, the H2—CI2 unitized regenerative fuel cell (URFC) is an excellent energy storage device as discussed later. 

Barbir, F., Molter, T., and Dalton, L. (2005) Efficiency and weight trade-off analysis of regenerative fuel cells as energy storage for aerospace applications. Int. J. Hydrogen Energy, 30, 351-357. 

Burke, K.A. (2005) Unitized Regenerative Fuel Cell System Gas Storage-Radiator Development. Technical Memorandum NASA/TM2005-213442, NASA. 

Regenerative Fuel Cells, Fig. 1 Renewable energy storage using a regentaative fuel cell system... 

Fujiwara et al. (2011) showed the possibility of preparing reversible air electrodes that can be used in metal-air storage batteries or unitized regenerative fuel cells. To reduce the impact of atmospheric carbon dioxide the reversible air electrodes were integrated with a polymer anion-exchange membrane which was placed between the cathode s catalytic layer (with Pt and Pt-Ir catalysts) and the alkaline solution. The membrane with anion permselectivity presumably inhibited the permeation of COj cations to the air electrode and thus suppressed precipitation of carbonates in pores of the air electrode. 

Barbir, F., T. Molter, and L. Dalton, Efficiency and Weight Trade-off Analysis of Regenerative Fuel Cells as Energy Storage for Aerospace Applications, International Journal of Hydrogen Energy, Vol. 30, No. 4, 2005, pp. 231-238. 

Figure 3.52. Efficiency of a reversible PEM fuel cell as a function of the amount (at. % or mol %) of Ir in the form of IrOj relative to Pt in the positive electrode catalyst, for fuel cell electricity production (EC) or for water electrolysis (WE). Also the product of the two efficiencies relevant for storage cycles is shown. The catalyst is otherwise similar to that of Fig. 3.51, with PTFE and Nation channels. (From T. loroi, K. Ya-suda, Z. Siroma, N. Fujiwara, Y. Miyazaki (2002). Thin film electrocatalyst layer for unitized regenerative polymer electrolyte fuel cell. J. Power Sources 112, 583-587. Used by permission from Elsevier. See also loroi et al. (2004).

Furthermore hydrogen can also serve multiple applications, in contrast to other storage mediums. If produced with regenerative energies, hydrogen stands for carbon dioxide free fuel, for instance to run any vehicle with fuel cells inside. 

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