J. Electrochem. Sci. Technol., 2018, 9(2), 141-148 - 141 - Analysis of Cell Performance with Varied Electrolyte Species and Amounts in a Molten Carbonate Fuel Cell Ki-Jeong Lee, Yu-Jeong Kim, Samuel Koomson, and Choong-Gon Lee* Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 Korea ABSTRACT This study evaluated the performance characteristics of varied electrolyte species and amounts in a molten carbonate fuel cell (MCFC). Coin-type MCFCs were used at the condition of 650 C and 1 atm. In order to measure the effects of varied electrolyte species and amounts, electrolytes of (Li+K) CO and (Li+Na) CO were selected and the amounts of 1.5 g, 2.0 g, 3.0 g, and 4.0 g were used. Insignificant performance differences were observed in the cell using different electro- lytes, but the cell performance was sensitive to the amount of the electrolyte used. The pore-filling ratio (PFR), a ratio of pore filling in the components by the liquid carbonate electrolytes, was used to determine the optimum performance range. Consequently, 77% PFR demonstrated the optimum performance for both electrolytes. Thus, the MCFC had a permissible but narrow optimum performance range. The remaining amounts of electrolyte in the cells were determined using the weight reduction ratio (WRR) method after several hours of cell operation. The WRR used the relationship between the initial loaded amount of electrolyte and weight reduction of components in 10 wt% acetic acid. The relationships were lin- ear and identical between the two electrolyte species. Keywords : Molten carbonate fuel cell, Performance, Pore filling ratio, Electrolyte species, Electrolyte amount Received : 5 March 2018, Accepted : 9 April 2018 1. Introduction The molten carbonate fuel cell (MCFC) is one of the fuel cell systems that directly convert chemical energy into electrical energy. The main feature of the MCFC is the production of clean and efficient energy at high temperatures between 600 and 700 o C. Other advantages include more flexibility in fuel choices and lower required catalyst amounts as compared to those with other fuel cells [1-6]. A characteristic property of a molten carbonate is its ability to change into a liquid at high temperatures, i.e., over 500 o C; in addition, it can conduct electricity as an electrolyte. The melted carbonate easily impregnates porous materials and blocks leakage of the cell com- ponents, thereby preventing leakage of the fuel gas [7-8]. Therefore, the molten salt electrolyte is an important material in MCFCs. However, the prob- lem of electrolyte consumption exists at the high- temperature operation conditions over 600 o C. In a previous study, it was reported that electrolyte degra- dation increases the internal resistance and polariza- tion resistance [9]. This means that, as the amount of electrolyte decreases, the cell performance and life- time both decrease. Thus, the electrolyte in the cell has significant effects on the cell performance and lifetime of the MCFC. Therefore, if the optimum electrolyte is used in the cell, the maximum perfor- mance and longest cell life can be obtained. In the MCFC, the electrolyte impregnates porous materials such as the anode, cathode, and matrix. The anode, comprising a Ni-Al alloy, has low wettability and a high contact angle with molten carbonates. Therefore, the anode is covered with a thin layer of the electrolyte. The Li-doped NiO cathode is the *E-mail address: leecg@hanbat.ac.kr DOI: https://doi.org/10.5229/JECST.2018.9.2.141 Research Article Journal of Electrochemical Science and Technology