Masahiro Yanagida

Cell performance of molten-carbonate fuel cell with alkali and alkaline-earth carbonate mixtures

Abstract Molten-carbonate fuel cells with two types of alkali carbonate mixture as the electrolyte have been operated. The resulting cell performances have been compared in order to optimize the composition of each carbonate mixture. One electrolyte type is a mixture of the high lithium eutectic ((Li 0.62 K 0.38 ) 2 CO 3 ) and an alkaline-earth carbonate, while the other is a mixture of the lithium-sodium eutectic ((Li 0.52 Na 0.48 ) 2 CO 3 ) and an alkaline-earth carbonate. Additions of CaCO 3 , SrCO 3 and BaCO 3 have been used. A small amount of each alkaline-earth carbonate to both eutectics does not influence the cell performance. On the other hand, larger amounts reduce the cell performance. The required content of each additive to provide optimum cell performance depends on both the additive itself and the host eutectic. The temperature dependence of cell performance in the presence of the different additives has also been investigated. There is little difference between the behaviour of ((Li 0.62 K 0.38 K 0.38 ) 2 Ca)CO 3 , ((Li 0.62 K 0.38 ) 2 Ba)CO 3 and ((Li 0.52 Na 0.48 ) 2 Ca)CO 3 . By contrast, high temperature dependence was found for ((Li 0.62 K 0.38 ) 2 Sr)CO 3 , ((Li 0.52 Na 0.48 ) 2 Sr)CO 3 and ((Li 0.52 Na 0.48 ) 2 Ba)CO 3 .

Cell performance of molten carbonate fuel cell with alkali carbonate eutectic mixtures

Abstract Molten carbonate fuel cells with four alkali carbonate eutectic mixtures of Li 2 CO 3 /Na 2 CO 3 /K 2 CO 3 in the proportions 62/0/38, 43/0/57, 43/32/25 and 52/48/0 (mol%), have been operated using electrolyte matrices fabricated by tape casting. When the ratio of electrolyte volume to matrix pore volume was optimized, all of the test cells gave similar good performance.

Solubility of LiCoO/sub 2/ in molten carbonates

The solubility of LiCoO/sub 2/ was proportional to Pco/sub 2//sup 3/2/ and Po/sub 2//sup -1/4/ in (Li/sub 0.52/Na/sub 0.48/)/sub 2/CO/sub 3/. It obeys the acidic dissolution mechanism. This result was the same dependence as that in (Li/sub 0.62/K/sub 0.38/)/sub 2/CO/sub 3/. The solubility of LiCoO/sub 2/ in (Li/sub 0.52/Na/sub 0.48/)/sub 2/CO/sub 3/ was about a half of that in (Li/sub 0.62/K/sub 0.38/)/sub 2/CO/sub 3/. The solubility of LiCoO/sub 2/ decreased with Li content in Li-K carbonate system. The solubility of LiCoO/sub 2/ was lower than that of NiO even under the pressurized cathode condition of MCFC.

Long term operation of the 100-cm{sup 2} class single cell of MCFC

The R&D on Molten Carbonate Fuel Cell (MCFC) is proceeding as one of the New Sun Shine Project sponsored by Japanese government. In ONRI (Osaka National Research Institute), the tested MCFCs were assembled with the state-of-the-art components and operated under the load condition for 40000 hours and 34000 hours. We analyzed the performance reduction.

High temperature corrosion of separator materials for MCFC

The Molten Carbonate Fuel Cell (MCFC) is one of promising high efficiency power generation devices with low emission. Molten carbonate used for its electrolyte plays an important role in MCFC. It separates between anode and cathode gas environment and provides ionic conductivity on MCFC operation. Stainless steel is conventionally used as separator/current collector materials in MCFC cathode environment. As corrosion of the components of MCFC caused by the electrolyte proceeds with the electrolyte consumption, the corrosion in the MCFC is related to its performance and life. To understand and inhibit the corrosion in the MCFC is important to realize MCFC power generation system. We have studied the effect of alkaline earth carbonate addition into carbonate on corrosion of type 316L stainless steel. In this paper, we describe the effect of the temperature on corrosion behavior of type 316L stainless steel with carbonate mixture, (Li{sub 0.62}K{sub 0.38}){sub 2}CO{sub 3}, under the cathode environment in out-of-cell test.

Corrosion study on ceramics for conductance measurements of molten carbonates

Abstract In order to find corrosion-resistant materials applicable to a conductance cell used in a conductance measurement apparatus for molten carbonates, several ceramics were examined for durability in both hydrochloric acid solution and carbonate melt. It was found that beryllia-based ceramics and alumina ceramics of high purity exhibited high corrosion-resistance against those agents, and could be applied in conductance cells. This article gives valuable criteria for the application of potential ceramic materials in carbonate melts.