A study on LiCoO 2-rich cathode materials for the MCFC based on the LiCoO 2–LiFeO 2–NiO ternary system

Abstract

A study performed in LiCoO 2-rich LiCoO 2–LiFeO 2–NiO ternary materials for the molten carbonate fuel cell (MCFC) cathodes is reported in this paper. LiCoO 2–LiFeO 2–NiO ternary materials are considered as more viable alternatives to lithiated NiO, however, the work reported so far has mainly been focused on ternary compositions rich in LiFeO 2 or NiO. The present work was carried out by investigating the electrical conductivity and microstructural characteristics of the new materials first in the form of bulk pellets and then in ex situ sintered porous-gas-diffusion (PGD) cathodes. The material study reveals the ability of preparing LiCoO 2–LiFeO 2–NiO ternary compositions with adequate electrical conductivity by controlling the LiCoO 2 content. A bimodal pore structure, appropriate for the MCFC cathode, could be achieved in sintered cathodes prepared with fine powders and pore formers. Further, the cathode fabrication study indicates the nature of the compromise to be made between the electrical conductivity, phase purity, pore structure and porosity in optimization cathodes for MCFC application. The study shows the possibility of preparing LiCoO 2-rich LiCoO 2–LiFeO 2–NiO cathodes with promising electrical and pore structural characteristics for the MCFC.