Thursday, 5 October 2017: 16:50
Maryland A (Gaylord National Resort and Convention Center)
A problem with the practial realization of the aluminum air battery is that byproducts such as Al(OH)3 or Al2O3 accumulate on the electrodes during electrochemical reaction. The goal of this study is to develop a practical, high-capacity rechargeable aluminum–air battery that resists degradation. We attempted to use different types of active materials for the air-cathode material and used a mixture of AlCl3 and 1-ethyl-3-methylimidazolium chloride as an ionic-liquid-based electrolyte. The air-cathode materials were activated carbon, carbon alloy, ceramic perovskite oxide, aluminum terephthalate as metal–organic framework (MOF), as well as non-oxide ceramic materials such as TiN, TiC, and TiB2. When we used carbon alloy as the air-cathode material, it initially exhibited an electrical current greater than those of the other air cathode materials because of its high catalytic activity in oxygen reduction, although its effect decreased as the charge–discharge reaction proceeded. Ceramic perovskite oxide (LSCF : La0.6Sr0.4Co0.2Fe0.8O3), TiN, and TiC demonstrated stable performance in electrochemical reactions over the long term. In contrast to aqueous-electrolyte-based aluminum–air battery system, our aluminum–air battery did not show typical byproducts on the aluminum anode side after the electrochemical reaction, such as Al(OH)3 or Al2O3, although we observed them on the air cathode side. However, byproduct formation was suppressed when TiN and TiC were used as air-cathode materials. To our knowledge, this is the first report of suppressed formation of such byproducts on both anode and air cathode in an aluminum–air battery. Our results suggest that byproducts accumulate on the air cathode via reaction of aluminum carbonate, which is suppressed with the TiC air cathode.