All solid-state protonic batteries

1 A solid-state battery with a proton conducting electrolyte 

A solid protonic electrolyte battery presents the general advantages of all solid-state systems such as absence of liquid leakage and ease of handling. It must have two electrodes to react with the protons, as in aqueous liquid electrolyte batteries. The main aim for using solid protonic conductors resides in the possibility of using similar electrodes to those in current commercial batteries. 

2 Advantages and problems of batteries with a Uqtddproton conducting electrolyte 

The main advantages of batteries with a liquid electrolyte come from the high conductivity exhibited by the usual concentrated solutions, sulphuric acid and potash, and from the good interface between electrolyte and electrode material, which allows high current densities to be achieved. Electrode materials of these batteries have been in continuous improvement throughout this century they now have a good faradic efficiency and a reasonable cost. 

The main reaction involved with all these electrode materials is a proton insertion/deinsertion which supplies protons to the electrolyte when electrodes are anodically polarized and catches protons from the electrolyte when they are cathodically polarized. This protonic cathode-anode exchange can be pointed out in the following reactions. 

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In an ideal solid-state battery involving protonic reactions, the solid electrolyte must be only a protonic conductor the proton transference number should be equal to unity (t(H+> = 1). Then all the previous reactions cannot occur and it is theoretically possible to use electrode materials which were unstable in the presence of a liquid aqueous electrolyte. 

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