Polymeric Electrode for Sodium Borohydride Fuel Cell

Reported here is the first example of sodium borohydride fuel cell constructed with electro-active conducting Polycarbazole (Pcz) and oxygen cathode. A Pcz electrode is made by depositing a thin film of the polymer on Stainless Steel (SS) substrate. The multistage oxidation process of borohydride is expected to involve 8e⁻ with borate as the end product. The oxidative process at the Pcz electrode has been examined by Cyclic Voltametry (CV). The direct oxidation of borohydride on SS was not observed in CV; however it is distinctly visible at the Pcz electrode. The borohydride oxidation at the Pcz electrode occurs at Ep = −0.29 V vs. saturated calomel electrode (SCE). The process was studied using scan rates of 10 mV/s to 100 mV/s. The anodic peak current increases linearly with the sweep rate and also with concentration of borohydride, suggesting that the oxidative process is diffusion controlled. The mechanism of borohydride oxidation has been investigated and compared with the oxidation on platinum or gold electrode. The results suggest that the borohydride fuel cell as operating efficiently with the Pcz anode or cathode. Preliminary results will be reported.