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A study on the deformation of porous nickel oxide cathode materials in MCFC
Solid State Ionics 148 (2002) 539 – 544 www.elsevier.com/locate/ssi
A study on the deformation of porous nickel oxide cathode materials in MCFC Li-Jiang Chen a, Chang-Jian Lin a,*, Xuan Cheng a, Zu-De Feng b a State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen 361005, China State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China
b
Abstract A home-made LVDT displacement-measuring system was developed and applied to study the process of deformation on NiO during early stage of molten carbonate fuel cell (MCFC) operation. A series of in situ deformation tests was performed at a normal temperature (923 K) with porous Ni and NiO plaques under the atmospheres and load conditions in the presence of carbonate electrolyte. The results indicated that the most significant deformation took place when Ni plaque underwent both in situ oxidized and lithiated processes under a load condition, in particular, the deformation of Ni plaque occurred more severely at the beginning of processes. D 2002 Elsevier Science B.V. All rights reserved. Keywords: MCFC; NiO cathode; Carbonates; Loading; Deformation
1. Introduction The molten carbonate fuel cell (MCFC) is believed to be one of the most promising efficient devices for conversion of chemical energy into electricity [1– 4]. But the dissolution of lithiated NiO cathode in molten carbonates and its structural degradation during operation of cell is one of the major factors to limit the cell life. In recent years, lots of efforts have been made to develop the alternative cathode materials [5– 7]. Some composite cathode materials and the cathode-adhibited rare earth elements have also been studied [8– 10]. Nevertheless, the NiO cathode still possesses its attraction owing to the relative fine cathode performance, low costs and mature technique of industrial manufacture. In spite of lots of research about NiO
cathode, there are relatively few reports studying the premature deterioration of NiO cathode during in situ oxidation and lithiation of Ni. Yazici and Selman [11,12], Tomcayk and Mosialek [13] and Izaki and Mugikura [14] have investigated the nickel behavior of in situ oxidation lithiation without a load, but in MCFC stack, the actual oxidation lithiation process occurs under loading condition. Murai and Takizawa et al. [15] probed into the deformation mechanism of porous NiO and lithiated NiO in CO2 atmosphere, not involving porous Ni, in carbonates under loading condition. In the study, the deformation of porous Ni and NiO was respectively investigated under a loading in molten carbonates and mixed atmospheres.
2. Experimental *
Corresponding author. E-mail address: [email protected] (C.-J. Lin).
The porous nickel oxide plaques were obtained by sintering porous nickel plaques with 0.909 mm thick-
0167-2738/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 2 7 3 8 ( 0 2 ) 0 0 0 9 6 - 6
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L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
The in situ deformation tests were performed in the home-made deformation-testing system, and Fig. 1 shows the schematic representation of the system. The studied samples (pre-lithiated NiO, NiO and Ni plaques with 1 cm2 area) together with 2 g Li/K eutectic carbonates were placed within an alumina crucible (40 mm diameter and 60 mm height) in a stainless steel vessel of the system. In the vessel, the testing temperatures can be controlled and the gases are allowed to flow at certain rate through it. Here the gases were mainly the mixture of CO2, O2 and N2 with a ratio of 0.20:0.15:0.65 and the flow rate was 50 ml/min. The detailed information about testing samples and conditions are listed in Table 1. The change in thickness of samples with time were directly measured by LVDT and automatically recorded by a computer connected with the testing system. After deformation tests, the post-experimental samples were disposed by deionized water to dissolve and remove the carbonates covered with the surface of samples, then were characterized by scanning electron microscope (SEM).
Fig. 1. A schematic representation of the deformation-testing system. I: Gas-controlling apparatus; II: temperature-controlling apparatus; III: LVDT apparatus; IV: computer (for recording); V: adjustable level-support; VI: stable table. 1: Stainless steel vessel; 2: thermocouple; 3: loading; 4: steady frame of loading; 5: LVDT sensor; 6: Al2O3 support; 7: sample; 8: Al2O3 plate; 9: Al2O3 rod.
3. Results and discussion In Experiments 1 and 2, the deformation behaviors of porous nickel oxide and nickel plaques with 1 cm2 area were studied under 1.96105 N/m2 load in the absence of carbonate electrolytes at 953 K in air. The curves in Fig. 2 show that under the same load, the change in thickness of both NiO and Ni plaque was about 2.5% and there was no obvious difference within 70 test hours when the molten carbonates were not existent, although the deformation curve of Ni
ness and 70% porosity (provided by ERC) at 1073 K for 7 h in air. And the crystal structure of these prepared samples was identified to be NiO by X-ray diffraction analysis. In addition, the pre-lithiated NiO were made by immersing porous nickel oxide or nickel plaques in molten Li/K (62:38 mol%) eutectic carbonates at 923 K for 20 h without a load in mix atmospheres containing CO2, O2 and N2 with a ratio of 0.20:0.15:0.65. Table 1 Information of testing samples and conditions Testing no.
Testing sample
Carbonate electrolyte
Atmosphere (1 atm)
Temperature (K)
Load (105 N/m2)
Testing time (h)
1 2 3
NiO Ni NiO
Absence
Air
953
1.96
70
2 g Li/K eutectic carbonate
Mix atmospheres CO2/O2/N2 0.20:0.15:0.65
923
3.43
100
4 5
Ni Pre-lithiated NiO (from NiO) Pre-lithiated NiO (from Ni)
6
L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
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went up after 50 h of tests. The results indicate that in the absence of carbonates, the in situ oxidation of Ni under a load in air did not result in apparent deformation. Experiments 3 and 4 were carried out under 3.43 105 N/m2 load in the presence of molten Li/K carbonates at 923 K in mix atmospheres of CO2, O2 and N2 with a ratio of 0.20:0.15:0.65. The testing samples were NiO and Ni plaque, respectively. It can be seen from Fig. 3 that the two deformation curves differed considerably. The deformation curve of NiO fell with time during the first 5 h, which may be attributed to the expansion of sample brought by the lithiation, and then slowly went up with the increase of testing time. On the contrary, the deformation curve of Ni initially
rose very quickly, and then changed to be even after 20 h of test, when the lithium-doped NiO possibly had formed. The results from comparing the curve A with B indicate that the deformation of Ni plaque occurred much more severely on the whole than that of NiO when being in situ oxidized and lithiated under loading conditions. In Experiments 5 and 6, NiO and Ni samples were first lithiated and oxidized for about 20 h without being applied to a load, and then the change of their thickness under 3.43105 N/m2 load was in situ measured. As shown in Fig. 4, no apparent deformation was observed for pre-lithiated sample ‘‘A’’ made by directly doping lithium into NiO plaque. Comparatively, the deformation of pre-lithiated sample ‘‘B’’, by oxidizing and lithium-doping Ni, shown by Curve B in Fig. 4 appeared to be a little more evident; however, comparing with Curve B in Fig. 3, the deformation was much less conspicuous. It reveals that the Ni plaque in the case of being pre-oxidized and lithiated before loading did not deform severely. The SEM results of post-tested samples were obtained after the carbonates covering surfaces of the samples were removed. In Fig. 5, the SEM photographs of original Ni plaque and the Ni samples after Tests 4 and 6 are shown. The structure of porous green Ni plaque in Fig. 5(a) appeared to be branch shaped with clear outline and the shape of nickel particles were not observed, which is possibly due to the particles’ connection with each other by casting reagents used in the manufacture process of Ni plaques. It was
Fig. 3. Deformation curves of NiO and Ni obtained under 3.43105 N/m2 load and 1 atm mix atmospheres at 923 K in the presence of Li/K carbonate.
Fig. 4. Deformation curves of pre-lithiated NiO and Ni obtained under 3.43105 N/m2 load and 1 atm mix atmospheres at 923 K in the presence of Li/K carbonate.
Fig. 2. Deformation curves of NiO and Ni obtained under 1.96105 N/m2 load and 1 atm air at 953 K in the absence of Li/K carbonate.
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Fig. 5. SEM photographs of porous Ni samples before and after tests. (a) Green porous Ni; (b) Ni sample after Test 4; (c) Ni sample after Test 6; (d) Ni sample immersed in carbonates for 100 h without loading under same temperature and atmospheres as that in Tests 4 and 6.
Fig. 6. SEM photographs of porous NiO samples before and after tests. (a) Prime porous NiO; (b) NiO sample after Test 3; (c) NiO sample after Test 5.
L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
found that both of the morphology shown, respectively, in Fig. 5(c) and (d), were still branch shaped and basically similar to that of green Ni. In contrast, the sample structure in Fig. 5(b) changed to be very different from green Ni with failing to observe branch structure. The sample surface was seemed to be blasted and there were much more nanophase needle projections on surface than that in Fig. 5(c) and (d). The results of energy dispersive spectroscopy (EDS) indicate that the composition of needle projections was mainly Ni and O. So the projections were possibly formed by the reprecipitation of dissolving nickel ions and the O2 ions in molten carbonates. Based on the above SEM results, it was concluded that the structure of porous Ni plaque was destroyed severely if a loading was applied to the sample at the initial 20 h of oxidation and lithiation of porous Ni, which was consistent with the results of deformation tests. As evident in Fig. (6), the morphology of porous NiO samples after deformation tests had hardly obvious change comparing with that of primal NiO plaque. The results reveal nickel oxide was considerably stable in the process of lithium ions incorporation even under condition of stress being applied. Yazici and Selman [11] have studied the in situ oxidation of nickel foil in molten carbonates and confirmed that three stages existed in the oxidation process. During the early stages of the oxidation and lithiation process, most of the corrosion product of nickel spalls into the melt. Here it can be inferred, in Test 4 when the surface of porous Ni formed a NiO film in the early stage of oxidation lithiation, a stress applied to sample accelerated the spalling of NiO layer and caused severe deformation. On the other hand, during the process, the generation of many defects of Ni vacancies also probably resulted in an evident deformation of porous Ni. While the little deformation of nickel oxide under a load was attributed to the relatively complete oxidation of sample before contacting with molten carbonates, the thick NiO layer was rather stable in melts. Under the operation of MCFC stack, a premature deterioration can happen caused by the in situ oxidation and lithiation of porous Ni under loading at the starting of stack; moreover, in this case, many Ni2+ ions dissolving from NiO film can precipitate in the electrolyte matrix and be a bane for future short circuit. Based on the mentioned discussion, a composite ma-
543
terial consisting of Ni and NiO or pre-oxidized Ni plaque before contacting with molten carbonates is perhaps able to relieve the detriment considerably.
4. Conclusions Under the condition simulating operating environment (in situ oxidized and lithiated under loading and mixed atmospheres), Ni deformation took place most significantly, in particular, at the beginning of the process. However, Ni deformation lessened when being in situ oxidized and lithiated for 20 h before loading. Contrastively, only minor deformation of NiO was observed in all cases. According to these, a proposal is obtained that at the starting operation of MCFC, Ni-based cathodes in MCFC stack are preferably pre-oxidized for a period before carbonate electrolytes are molten to avoid the stack deformation and premature dissolution of NiO electrode.
Acknowledgements This work was supported by the Natural Science Foundation of China and Energy Research Corporation, U.S.A.
References [1] L. Blomen, M. Mugerwa (Eds.), Fuel Cell Systems, Plenum, New York 1993. [2] J. Appleby, F. Foulkes, Fuel Cell Handbook, Van NostrandReinhold, New York 1990. [3] J.R. Selman, T.D. Claar (Eds.), Molten Carbonate Fuel Cell Technology, The Electrochemical Society, Pennington, NJ 1982. [4] K.I. Ota, B.T. Kim, et al., High temperature corrosion of metals with molten carbonate, Proceedings of the Fifth China – Japan Bilateral Conference on Molten Chemistry and Technology, Kunming, China, Sept. 28 – Oct. 2, Printed by Kunming Technology University (1994), p. 42. [5] Molten carbonate fuel cell technology, in: J.R. Selman, D.A. Shores, H.C. Maru, I. Uchida (Eds.), PV 90-16, The Electrochemical Society Softbound Proceeding Series, The Electrochemical Society, Pennington, NJ, 1990. [6] L. Plomp, E.F. Sitters, et al., J. Electrochem. Soc. 138 (1991) 629. [7] G.L. Lee, J.R. Selman, et al., J. Electrochem. Soc. 140 (1993) 390.
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[8] Seung Aaek Kuk, Young Seck Song, et al., J. Power Sources 83 (1999) 50. [9] Takehisa Fukui, Satoshi Ohara, et al., J. Power Sources 86 (2000) 340. [10] Beizeng Fang, Hong Chen, J. Electroanal. Chem. 50 (2001) 128. [11] M.S. Yazici, J.R. Selman, J. Electroanal. Chem. 457 (1998) 89.
[12] M.S. Yazici, J.R. Selman, Solid State Ionics 124 (1999) 149. [13] P. Tomcayk, M. Mosialek, J. Electroanal. Chem. 463 (1999) 72. [14] Yoshiyuki Izaki, Yoshihiro Mugikura, J. Power Sources 75 (1998) 236. [15] M. Murai, K. Takizawa, et al., J. Electrochem. Soc. 143 (1996) 2481.
A study on the deformation of porous nickel oxide cathode materials in MCFC Li-Jiang Chen a, Chang-Jian Lin a,*, Xuan Cheng a, Zu-De Feng b a State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Xiamen University, Xiamen 361005, China State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China
b
Abstract A home-made LVDT displacement-measuring system was developed and applied to study the process of deformation on NiO during early stage of molten carbonate fuel cell (MCFC) operation. A series of in situ deformation tests was performed at a normal temperature (923 K) with porous Ni and NiO plaques under the atmospheres and load conditions in the presence of carbonate electrolyte. The results indicated that the most significant deformation took place when Ni plaque underwent both in situ oxidized and lithiated processes under a load condition, in particular, the deformation of Ni plaque occurred more severely at the beginning of processes. D 2002 Elsevier Science B.V. All rights reserved. Keywords: MCFC; NiO cathode; Carbonates; Loading; Deformation
1. Introduction The molten carbonate fuel cell (MCFC) is believed to be one of the most promising efficient devices for conversion of chemical energy into electricity [1– 4]. But the dissolution of lithiated NiO cathode in molten carbonates and its structural degradation during operation of cell is one of the major factors to limit the cell life. In recent years, lots of efforts have been made to develop the alternative cathode materials [5– 7]. Some composite cathode materials and the cathode-adhibited rare earth elements have also been studied [8– 10]. Nevertheless, the NiO cathode still possesses its attraction owing to the relative fine cathode performance, low costs and mature technique of industrial manufacture. In spite of lots of research about NiO
cathode, there are relatively few reports studying the premature deterioration of NiO cathode during in situ oxidation and lithiation of Ni. Yazici and Selman [11,12], Tomcayk and Mosialek [13] and Izaki and Mugikura [14] have investigated the nickel behavior of in situ oxidation lithiation without a load, but in MCFC stack, the actual oxidation lithiation process occurs under loading condition. Murai and Takizawa et al. [15] probed into the deformation mechanism of porous NiO and lithiated NiO in CO2 atmosphere, not involving porous Ni, in carbonates under loading condition. In the study, the deformation of porous Ni and NiO was respectively investigated under a loading in molten carbonates and mixed atmospheres.
2. Experimental *
Corresponding author. E-mail address: [email protected] (C.-J. Lin).
The porous nickel oxide plaques were obtained by sintering porous nickel plaques with 0.909 mm thick-
0167-2738/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 2 7 3 8 ( 0 2 ) 0 0 0 9 6 - 6
540
L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
The in situ deformation tests were performed in the home-made deformation-testing system, and Fig. 1 shows the schematic representation of the system. The studied samples (pre-lithiated NiO, NiO and Ni plaques with 1 cm2 area) together with 2 g Li/K eutectic carbonates were placed within an alumina crucible (40 mm diameter and 60 mm height) in a stainless steel vessel of the system. In the vessel, the testing temperatures can be controlled and the gases are allowed to flow at certain rate through it. Here the gases were mainly the mixture of CO2, O2 and N2 with a ratio of 0.20:0.15:0.65 and the flow rate was 50 ml/min. The detailed information about testing samples and conditions are listed in Table 1. The change in thickness of samples with time were directly measured by LVDT and automatically recorded by a computer connected with the testing system. After deformation tests, the post-experimental samples were disposed by deionized water to dissolve and remove the carbonates covered with the surface of samples, then were characterized by scanning electron microscope (SEM).
Fig. 1. A schematic representation of the deformation-testing system. I: Gas-controlling apparatus; II: temperature-controlling apparatus; III: LVDT apparatus; IV: computer (for recording); V: adjustable level-support; VI: stable table. 1: Stainless steel vessel; 2: thermocouple; 3: loading; 4: steady frame of loading; 5: LVDT sensor; 6: Al2O3 support; 7: sample; 8: Al2O3 plate; 9: Al2O3 rod.
3. Results and discussion In Experiments 1 and 2, the deformation behaviors of porous nickel oxide and nickel plaques with 1 cm2 area were studied under 1.96105 N/m2 load in the absence of carbonate electrolytes at 953 K in air. The curves in Fig. 2 show that under the same load, the change in thickness of both NiO and Ni plaque was about 2.5% and there was no obvious difference within 70 test hours when the molten carbonates were not existent, although the deformation curve of Ni
ness and 70% porosity (provided by ERC) at 1073 K for 7 h in air. And the crystal structure of these prepared samples was identified to be NiO by X-ray diffraction analysis. In addition, the pre-lithiated NiO were made by immersing porous nickel oxide or nickel plaques in molten Li/K (62:38 mol%) eutectic carbonates at 923 K for 20 h without a load in mix atmospheres containing CO2, O2 and N2 with a ratio of 0.20:0.15:0.65. Table 1 Information of testing samples and conditions Testing no.
Testing sample
Carbonate electrolyte
Atmosphere (1 atm)
Temperature (K)
Load (105 N/m2)
Testing time (h)
1 2 3
NiO Ni NiO
Absence
Air
953
1.96
70
2 g Li/K eutectic carbonate
Mix atmospheres CO2/O2/N2 0.20:0.15:0.65
923
3.43
100
4 5
Ni Pre-lithiated NiO (from NiO) Pre-lithiated NiO (from Ni)
6
L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
541
went up after 50 h of tests. The results indicate that in the absence of carbonates, the in situ oxidation of Ni under a load in air did not result in apparent deformation. Experiments 3 and 4 were carried out under 3.43 105 N/m2 load in the presence of molten Li/K carbonates at 923 K in mix atmospheres of CO2, O2 and N2 with a ratio of 0.20:0.15:0.65. The testing samples were NiO and Ni plaque, respectively. It can be seen from Fig. 3 that the two deformation curves differed considerably. The deformation curve of NiO fell with time during the first 5 h, which may be attributed to the expansion of sample brought by the lithiation, and then slowly went up with the increase of testing time. On the contrary, the deformation curve of Ni initially
rose very quickly, and then changed to be even after 20 h of test, when the lithium-doped NiO possibly had formed. The results from comparing the curve A with B indicate that the deformation of Ni plaque occurred much more severely on the whole than that of NiO when being in situ oxidized and lithiated under loading conditions. In Experiments 5 and 6, NiO and Ni samples were first lithiated and oxidized for about 20 h without being applied to a load, and then the change of their thickness under 3.43105 N/m2 load was in situ measured. As shown in Fig. 4, no apparent deformation was observed for pre-lithiated sample ‘‘A’’ made by directly doping lithium into NiO plaque. Comparatively, the deformation of pre-lithiated sample ‘‘B’’, by oxidizing and lithium-doping Ni, shown by Curve B in Fig. 4 appeared to be a little more evident; however, comparing with Curve B in Fig. 3, the deformation was much less conspicuous. It reveals that the Ni plaque in the case of being pre-oxidized and lithiated before loading did not deform severely. The SEM results of post-tested samples were obtained after the carbonates covering surfaces of the samples were removed. In Fig. 5, the SEM photographs of original Ni plaque and the Ni samples after Tests 4 and 6 are shown. The structure of porous green Ni plaque in Fig. 5(a) appeared to be branch shaped with clear outline and the shape of nickel particles were not observed, which is possibly due to the particles’ connection with each other by casting reagents used in the manufacture process of Ni plaques. It was
Fig. 3. Deformation curves of NiO and Ni obtained under 3.43105 N/m2 load and 1 atm mix atmospheres at 923 K in the presence of Li/K carbonate.
Fig. 4. Deformation curves of pre-lithiated NiO and Ni obtained under 3.43105 N/m2 load and 1 atm mix atmospheres at 923 K in the presence of Li/K carbonate.
Fig. 2. Deformation curves of NiO and Ni obtained under 1.96105 N/m2 load and 1 atm air at 953 K in the absence of Li/K carbonate.
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Fig. 5. SEM photographs of porous Ni samples before and after tests. (a) Green porous Ni; (b) Ni sample after Test 4; (c) Ni sample after Test 6; (d) Ni sample immersed in carbonates for 100 h without loading under same temperature and atmospheres as that in Tests 4 and 6.
Fig. 6. SEM photographs of porous NiO samples before and after tests. (a) Prime porous NiO; (b) NiO sample after Test 3; (c) NiO sample after Test 5.
L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
found that both of the morphology shown, respectively, in Fig. 5(c) and (d), were still branch shaped and basically similar to that of green Ni. In contrast, the sample structure in Fig. 5(b) changed to be very different from green Ni with failing to observe branch structure. The sample surface was seemed to be blasted and there were much more nanophase needle projections on surface than that in Fig. 5(c) and (d). The results of energy dispersive spectroscopy (EDS) indicate that the composition of needle projections was mainly Ni and O. So the projections were possibly formed by the reprecipitation of dissolving nickel ions and the O2 ions in molten carbonates. Based on the above SEM results, it was concluded that the structure of porous Ni plaque was destroyed severely if a loading was applied to the sample at the initial 20 h of oxidation and lithiation of porous Ni, which was consistent with the results of deformation tests. As evident in Fig. (6), the morphology of porous NiO samples after deformation tests had hardly obvious change comparing with that of primal NiO plaque. The results reveal nickel oxide was considerably stable in the process of lithium ions incorporation even under condition of stress being applied. Yazici and Selman [11] have studied the in situ oxidation of nickel foil in molten carbonates and confirmed that three stages existed in the oxidation process. During the early stages of the oxidation and lithiation process, most of the corrosion product of nickel spalls into the melt. Here it can be inferred, in Test 4 when the surface of porous Ni formed a NiO film in the early stage of oxidation lithiation, a stress applied to sample accelerated the spalling of NiO layer and caused severe deformation. On the other hand, during the process, the generation of many defects of Ni vacancies also probably resulted in an evident deformation of porous Ni. While the little deformation of nickel oxide under a load was attributed to the relatively complete oxidation of sample before contacting with molten carbonates, the thick NiO layer was rather stable in melts. Under the operation of MCFC stack, a premature deterioration can happen caused by the in situ oxidation and lithiation of porous Ni under loading at the starting of stack; moreover, in this case, many Ni2+ ions dissolving from NiO film can precipitate in the electrolyte matrix and be a bane for future short circuit. Based on the mentioned discussion, a composite ma-
543
terial consisting of Ni and NiO or pre-oxidized Ni plaque before contacting with molten carbonates is perhaps able to relieve the detriment considerably.
4. Conclusions Under the condition simulating operating environment (in situ oxidized and lithiated under loading and mixed atmospheres), Ni deformation took place most significantly, in particular, at the beginning of the process. However, Ni deformation lessened when being in situ oxidized and lithiated for 20 h before loading. Contrastively, only minor deformation of NiO was observed in all cases. According to these, a proposal is obtained that at the starting operation of MCFC, Ni-based cathodes in MCFC stack are preferably pre-oxidized for a period before carbonate electrolytes are molten to avoid the stack deformation and premature dissolution of NiO electrode.
Acknowledgements This work was supported by the Natural Science Foundation of China and Energy Research Corporation, U.S.A.
References [1] L. Blomen, M. Mugerwa (Eds.), Fuel Cell Systems, Plenum, New York 1993. [2] J. Appleby, F. Foulkes, Fuel Cell Handbook, Van NostrandReinhold, New York 1990. [3] J.R. Selman, T.D. Claar (Eds.), Molten Carbonate Fuel Cell Technology, The Electrochemical Society, Pennington, NJ 1982. [4] K.I. Ota, B.T. Kim, et al., High temperature corrosion of metals with molten carbonate, Proceedings of the Fifth China – Japan Bilateral Conference on Molten Chemistry and Technology, Kunming, China, Sept. 28 – Oct. 2, Printed by Kunming Technology University (1994), p. 42. [5] Molten carbonate fuel cell technology, in: J.R. Selman, D.A. Shores, H.C. Maru, I. Uchida (Eds.), PV 90-16, The Electrochemical Society Softbound Proceeding Series, The Electrochemical Society, Pennington, NJ, 1990. [6] L. Plomp, E.F. Sitters, et al., J. Electrochem. Soc. 138 (1991) 629. [7] G.L. Lee, J.R. Selman, et al., J. Electrochem. Soc. 140 (1993) 390.
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L.-J. Chen et al. / Solid State Ionics 148 (2002) 539 – 544
[8] Seung Aaek Kuk, Young Seck Song, et al., J. Power Sources 83 (1999) 50. [9] Takehisa Fukui, Satoshi Ohara, et al., J. Power Sources 86 (2000) 340. [10] Beizeng Fang, Hong Chen, J. Electroanal. Chem. 50 (2001) 128. [11] M.S. Yazici, J.R. Selman, J. Electroanal. Chem. 457 (1998) 89.
[12] M.S. Yazici, J.R. Selman, Solid State Ionics 124 (1999) 149. [13] P. Tomcayk, M. Mosialek, J. Electroanal. Chem. 463 (1999) 72. [14] Yoshiyuki Izaki, Yoshihiro Mugikura, J. Power Sources 75 (1998) 236. [15] M. Murai, K. Takizawa, et al., J. Electrochem. Soc. 143 (1996) 2481.