Li effects on layer-structured oxide LixNi0.8Co0.15Al0.05O2-?: Improving cell performance via on-line reaction

By Liu, Xueqi; Dong, Wenjing; Tong, Yuzhu; Wei, Lili; Yuan, Menghui; Wang, Xunying; Wang, Baoyuan; Zhu, Bin
Published in Electrochimica Acta 2019

Abstract

Li+ plays a critically important role in layer-structured LiNiO2 family oxides in that it affects the oxidant state of Ni and catalyst's function. Layer-structured LixNi0.8Co0.15Al0.05O2-? (LxNCA, x = 1, 1.2, 1.4) with different lithium content was prepared and applicated as both cathode and anode catalysts in symmetrical solid oxide fuel cell (SSOFC) that using samarium doped ceria (SDC) as electrolyte. Excess Li precursor resulted in the formation of Li2CO3 in L1.2NCA and L1.4NCA materials, whose influence on the performance of LxNCA was studied. Oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) of LxNCA as well as its catalytic stability were investigated by impedance spectroscopy. Its ORR process was found to be greatly influenced by the amount of Li in LxNCA while HOR was less related to Li content. Accompanying the on-line reduction and oxidation of LxNCA, fuel cells tested under reverse operation condition revealed enormous improvement in Pmax, which was due to the significant improvement of ORR process and the reduction of interface resistance.

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