Dissolution behavior of Co-coated NiO cathode in molten (Li0.62K0.38)2CO3 eutectics

Abstract The dissolution behavior of the NiO–CoO electrodes in molten (Li 0.62 K 0.38 ) 2 CO 3 eutectics as a function of Co content was investigated under the standard cathodic gas composition at 650 °C. In order to prepare NiO–CoO electrodes, Co was deposited on the porous Ni electrode using galvanostatic pulse plating technique followed by the oxidation process. Compared to the pure NiO electrode, NiO–CoO electrodes showed low Ni solubility in molten (Li 0.62 K 0.38 ) 2 CO 3 eutectics. Solubility of NiO–CoO electrodes depended on the partial pressure of carbon dioxide ( P CO 2 ) and the Ni solubility increased with P CO 2 . On the other hand, the Ni solubility was not affected by the partial pressure of oxygen ( P O 2 ). The XRD analysis after the dissolution experiment, showed that the Ni solubility decreased with increase of the amount of lithium incorporated in the electrodes and that the lithium incorporation was promoted by the formation of NiO–CoO solid solution. The results obtained in the present study suggested that NiO–CoO solid solution could effectively suppress the NiO dissolution in the molten (Li 0.62 K 0.38 ) 2 CO 3 eutectics.

[1]  Loreto Daza,et al.  Influence of lanthanum oxide as quality promoter on cathodes for MCFC , 2002 .

[2]  瀧澤 孝一,et al.  溶融炭酸塩形燃料電池カソード代替材料としてのLi-Co-Ni系複合酸化物の評価 , 2001 .

[3]  Keonkuk Kim,et al.  Properties of a new type of cathode for molten carbonate fuel cells , 1999 .

[4]  Suk Woo Nam,et al.  A stabilized NiO cathode prepared by sol-impregnation of LiCoO2 precursors for molten carbonate fuel cells , 2002 .

[5]  D. A. Shores,et al.  The Solubility of NiO in Binary Mixtures of Molten Carbonates , 1989 .

[6]  I. González,et al.  Formation Mechanisms and Characterization of Black and White Cobalt Electrodeposition onto Stainless Steel , 2000 .

[7]  Tatsuo Nishina,et al.  In situ NiO dissolution behavior in (Li + Na)CO3 melts under pressurized oxidant gas atmospheres , 1996 .

[8]  Koichi Takizawa,et al.  Behavior of CoO-NiO Solid Solution in Molten Carbonate , 2001 .

[9]  M. T. Casais,et al.  Modified nickel oxides as cathode materials for MCFC , 2000 .

[10]  Ralph E. White,et al.  Study of cobalt-doped lithium-nickel oxides as cathodes for MCFC , 2002 .

[11]  M. Naito,et al.  Performance and Morphology of a New Cathode Made from CoO/Ni Composite Particles for MCFCs , 2001 .

[12]  Bala Haran,et al.  Performance of La0.8Sr0.2CoO3 coated NiO as cathodes for molten carbonate fuel cells , 2003 .

[13]  Tsugio Sato,et al.  Preparation and electrical properties of LixM1−xO (M = Ni, Co) , 1986 .

[14]  B. Fang,et al.  Performance of a novel Ni/Nb cathode material for molten carbonate fuel cells (MCFC) , 2001 .

[15]  Yoji Fujita,et al.  Improvement of Lifetime of Molten Carbonate Fuel Cell. Effect of Fe and Co Additions on NiO Cathode Stability , 2002 .

[16]  A. Wijayasinghe,et al.  LiFeO2 ­ LiCoO2 ­ NiO Cathodes for Molten Carbonate Fuel Cells , 2003 .

[17]  N. Ibl,et al.  Influence of charge and discharge of electric double layer in pulse plating , 1980 .

[18]  J. Selman,et al.  Oxidation-lithiation of nickel, iron and cobalt in contact with molten carbonate , 1999 .

[19]  B. Fang,et al.  A new candidate material for molten carbonate fuel cell cathodes , 2001 .

[20]  Loreto Daza,et al.  Endurance test on a single cell of a novel cathode material for MCFC , 2002 .

[21]  Ralph E. White,et al.  Electrochemical Characterization of Cobalt-Encapsulated Nickel as Cathodes for MCFC , 2002 .

[22]  Chi-Chang Hu,et al.  Effects of electroplating variables on the composition and morphology of nickel–cobalt deposits plated through means of cyclic voltammetry , 2002 .

[23]  Satoshi Ohara,et al.  Properties of NiO cathode coated with lithiated Co and Ni solid solution oxide for MCFCs , 2000 .

[24]  Koichi Matsuzawa,et al.  Improvement of MCFC cathode stability by additives , 2002 .

[25]  A. Lundblad,et al.  Effect of sintering procedures in development of LiCoO2-cathodes for the molten carbonate fuel cell , 2000 .

[26]  Suk Woo Nam,et al.  Performance of LiCoO2-coated NiO cathode under pressurized conditions , 2002 .

[27]  S. Freni,et al.  The dissolution process of the NiO cathodes for molten carbonate fuel cells: state‐of‐the‐art , 1998 .

[28]  I. Uchida,et al.  Gas electrode reactions in molten carbonate media Part I. Exchange current density of oxygen reduction in (Li + K)CO3 eutectic at 650°C , 1986 .

[29]  Michael T. Lanagan,et al.  The Development of LiFeO2 ‐ LiCoO2 ‐ NiO Cathodes for Molten Carbonate Fuel Cells , 1999 .

[30]  I. Uchida,et al.  Solubility of in-situ oxidized NiO in (62 + 38)mol.% (Li + K)CO3 melt under pressurized conditions , 1995 .

[31]  S. Scaccia.  Determination of traces of Ni, Co and Fe in Li(2)CO(3)/K(2)CO(3) melts by flame atomic absorption spectrometry. , 1999, Talanta.

[32]  X. Liu,et al.  Effect of Mg on the solubility of NiO in molten carbonate , 1999 .

[33]  Makio Naito,et al.  Synthesis of CoO/Ni composite powders for molten carbonate fuel cells , 2001 .