Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Apparatus for Operando X-ray Diffraction of Fuel Electrodes in High
  Temperature Solid State Electrochemical Cells   Characterizing electrochemical energy conversion devices during operation is
an important strategy for correlating device performance with the properties of
cell materials under real operating conditions. While operando characterization
has been used extensively for low temperature electrochemical cells, these
techniques remain challenging for solid oxide electrochemical cells due to the
high temperatures and reactive gas atmospheres these cells require. Operando
X-ray diffraction measurements of solid oxide electrochemical cells could
detect changes in the crystal structure of the cell materials, which can be
useful for understanding degradation process that limit device lifetimes, but
the experimental capability to perform operando X-ray diffraction on the fuel
electrodes of these cells has not been demonstrated. Here we present the first
experimental apparatus capable of performing X-ray diffraction measurements on
the fuel electrodes of high temperature solid oxide electrochemical cells
during operation under reducing gas atmospheres. We present data from an
example experiment with a model solid oxide cell to demonstrate that this
apparatus can collect X-ray diffraction spectra during electrochemical cell
operation at high temperatures in humidified H2 gas. Measurements performed
using this apparatus can reveal new insights about solid oxide fuel cell and
solid oxide electrolyzer cell degradation mechanisms to enable the design of
durable, high performance devices.

37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph