IJSRST1841308 | Received:12Feb 2018 | Accepted :27 Feb 2018 | January-February-2018 [(4)2: 1397-1403]
© 2018 IJSRST | Volume 4 | Issue 2 | Print ISSN: 2395-6011 | Online ISSN: 2395-602X
Themed Section: Scienceand Technology
1397
NiO/YSZ Composite as a Precursor Material to SOFC Anodic
Application
V. Mohanta, S. Otta and B. K. Roul*
Institute of Materials Science, Planetarium Building, Acharya Vihar, Bhubaneswar, Odisha, India
ABSTRACT
The conventional solid state reaction route is used to prepare ceramic composite from commercially available
high-purity NiO (Aldrich, 99.99%) and YSZ (Aldrich, 99.9%) powders. Composites were characterized using X-
ray diffraction (XRD), field emission scanning electron microscopy (FESEM) techniques. The NiO/YSZ
composites were found to be in crystalline form with homogeneous mixture of YSZ and NiO phases. Impedance
measurements and analysis were performed over a frequency range 1 kHz to 2 MHz at different temperatures.
Conductivity in various temperature and different nickel contents were also studied which established the fact
that the development of NiO/YSZ composite showed remarkable anodic properties which are highly suitable to
be used as a precursor material for solid oxide fuel cell (SOFC).
Keywords: Solid state reaction route, NiO/YSZ composite, electrical properties, SOFC
I. INTRODUCTION
Solid oxide fuel cells (SOFCs) are solid-state
electrochemical devices that convert chemical energy
in fuels (H2 and Hydrocarbons etc) directly into
electrical energy with high efficiency [1]. Now a day,
SOFCs have received more attention due to not only
its high conversion efficiency but also high flexibility
to various fuels (H2, CH4, etc) and low pollution
emission [2]. In general, SOFCs consist of three main
parts: a dense electrolyte between two porous
electrodes (anode and cathode). Ni doped yttria
stabilized zirconia (Ni/YSZ) is the most widely used
anode material for SOFCs due to its high catalytic
activity of H2 oxidation, high mechanical/chemical
stability at high temperature, long term reliability,
low cost and their compatibility with most
electrolytes and interconnect materials [3]. The
electrochemical reaction inside the anode is supposed
to occur around the triple-phase boundary (TPB)
where the fuel gas, Ni and YSZ phase meet [4]. The
presence of Ni serves as an excellent catalyst for the
electrochemical oxidation of hydrogen whereas the
YSZ provides necessary framework for the dispersion
of Ni particles as well as offers ionic contribution to
the overall conductivity, which broadens the TPB [5].
Since polarization resistance of Ni/YSZ is strongly
influenced by its TPB [6], a reduction of polarization
resistance of the anode may be attributed to a longer
TPB, which enhances the electrochemical reaction [7].
Moreover, polarization resistance of the anode
depends on both Ni content and its micro structure [7].
So, to have a potential anode for SOFC applications a
finer micro structure along with uniform distribution
of Ni, YSZ and pores in the anode is essential [8],
which yields an improved electrochemical
performance.
In this research work, NiO/YSZ composite was
prepared by conventional solid state reaction route.
Appropriate amount of zinc was used here as pore
former. The composites were sintered at 1350
0
C for 5
hours. The aim of the present paper is to look into
anodic behaviour along with mechanism involved in
our sample. We investigated the effect of both Ni