The first experimental evidence of a new solar process, combining electronic and chemical pathways, to isolate CO2 (carbon capture) is presented. This solar thermal electrochemical photo (STEP) process is a synergy of solid-state and solar thermal processes, and is fundamentally capable of converting more solar energy than photovoltaic or solar thermal processes alone. Here, CO2 is captured using a 750−950 °C electrolysis cell powered by a full spectrum solar simulator in a single step. The process uses the full spectrum; solar thermal energy decreases the energy required for carbon capture, while visible sunlight generates electronic charge to drive the electrolysis. CO2 can be captured from 34% to over 50% solar energy efficiency (depending on the level of solar heat inclusion), as solid carbon and stored, or used as carbon monoxide to be available for a feedstock to synthesize (with STEP generated hydrogen) solar diesel fuel, synthetic jet fuel, or chemical production.
Higher capacity batteries based on an unusual stabilized iron(VI) chemistry are presented. The storage capacities of alkaline and metal hydride batteries are largely cathode limited, and both use a potassium hydroxide electrolyte. The new batteries are compatible with the alkaline and metal hydride battery anodes but have higher cathode capacity and are based on available, benign materials. Iron(VI/III) cathodes can use low-solubility K(2)FeO(4) and BaFeO(4) salts with respective capacities of 406 and 313 milliampere-hours per gram. Super-iron batteries have a 50 percent energy advantage compared to conventional alkaline batteries. A cell with an iron(VI) cathode and a metal hydride anode is significantly (75 percent) rechargeable.
In principle, alkali permanganates represent a substantial cathodic charge source for electrochemical storage, but high rate charge transfer has been inefficient. This study presents a novel Fe(VI) species (super-iron) and manganese redox chemistry synergism. Also presented is the high discharge energies from cathodes which utilize this phenomenon in a conventional cylindrical battery configuration. Batteries formed with a cathode combining BaFeO 4 and KMnO 4 , and using a conventional zinc alkaline anode in an AAA cylindrical cell configuration, exhibit an unusually high discharge capacity of 2.2 Wh. The discharge efficiency of solid alkaline permanganate or manganate cathodes is probed, and improved charge transfer of Mn(VII) redox chemistry in the presence of Fe(VI) is demonstrated. In a reciprocal manner, enhancement of Fe(VI) charge transfer are demonstrated upon inclusion of manganese salts, and also that added cesium further improves the combined Fe(V)/Mn(VII) cathode.
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