A novel high capacity, environmentally benign energy storage system: Super-iron boride battery

High electrochemical capacity of alkaline boride anodes is presented. The alkaline anodes based on transition metal borides (demonstrated with TaB, TaB2, TiB2 and VB2) can deliver exceptionally high discharge capacity. Over 2000 and 3800 mAh g−1 discharge capacities are obtained for the commercially available TiB2 and VB2 respectively, much higher than the theoretical capacity of commonly used zinc metal (820 mAh g−1) alkaline anode. Coupling with the super-iron cathodes, the novel Fe6+/B2− battery chemistry generates a matched electrochemical potential to the conventional MnO2–Zn battery, but sustains a much higher electrochemical capacity. High capacity TiB2 and VB2 anodes are further studied by coupling with a variety of cathodes (such as MnO2, NiOOH, KIO4 and composite K2FeO4/AgO). Both TiB2 and VB2 show good compatibilities with each of these cathodes. With the additive AgO to the super-iron (K2FeO4) cathode, a K2FeO4/AgO composite cathode TiB2 anode alkaline battery exhibits high-rate discharge performance.