Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Understanding the pseudocapacitance of RuO2 from joint density
  functional theory   Pseudocapacitors have been experimentally studied for many years in electric
energy storage. However, first principles understanding of the pseudocapacitive
behavior is still not satisfactory due to the complexity involved in modeling
electrochemistry. In this paper, we applied a novel simulation technique called
Joint Density Functional Theory (JDFT) to simulate the pseudocapacitive
behavior of RuO2, a prototypical material, in a model electrolyte. We obtained
from JDFT a capacitive curve which showed a redox peak position comparable to
that in the experimental cyclic voltammetry (CV) curve. We found that the
experimental turning point from double-layer to pseudocapacitive charge storage
at low scan rates could be explained by the hydrogen adsorption at low
coverage. As the electrode voltage becomes more negative, H coverage increases
and causes the surface structure change, leading to bended OH bonds at the
on-top oxygen atoms and large capacitance. This H coverage-dependent
capacitance can explain the high pseudocapacitance of hydrous RuO2. Our work
here provides a first principles understanding of the pseudocapacitance for
RuO2 in particular and for transition-metal oxides in general.

22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc