Chapter 1
Surface Thermodynamics of Solid
Electrode
Abstract Surface thermodynamics is fundamentals for understanding of the electrochemo-mechanical properties of solid electrode surfaces. The concept of surface
phase (or interphase) is explained, and the general equations of surface thermodynamics are derived. Surface stress is the most important thermodynamic parameter
to characterize a solid electrode, since the changes in surface stress are directly
associated with the electro-chemo-mechanical properties. The relationship between
surface stress and surface tension for a solid electrode is discussed to distinguish
from surface tension which characterizes a liquid electrode such as mercury electrode. Furthermore, the electrocapillary curve (surface stress vs. potential or surface
tension vs. potential) for the electrified interface of a solid electrode is derived and
compared with that (surface tension vs. potential) derived for the electrified interface of a liquid electrode. The difference between electrocapillary curves derived for
the electrified interfaces of solid and liquid electrodes is confirmed from the results
obtained experimentally for the electrified interfaces of gold and mercury electrodes.
Keywords Surface thermodynamics · Solid electrode · Surface stress · Surface
tension · Electrocapillary curve
1.1 Introduction
Surface thermodynamics is fundamentals for understanding of the electro-chemomechanical properties of solid electrode surfaces. This chapter deals with surface
thermodynamics of a solid electrode. In the interface region of two phases, the properties vary between those of bulk phase. Surface thermodynamics treats the interface region of two phases as one phase, i.e., surface phase (or interphase). At first,
the explanation for the concept of a surface phase (or interphase) has to precede
the derivation of the general equations of surface thermodynamics. Surface stress
is the most important thermodynamic parameter to characterize a solid electrode
since the changes in surface stress are directly associated with the electro-chemomechanical properties. The derivation of the relationship between surface stress and
surface tension for a solid electrode is indispensable for distinguishing a solid electrode from a liquid electrode such as mercury electrode. The electrocapillary curve
© Springer Nature Singapore Pte Ltd. 2020
M. Seo, Electro-Chemo-Mechanical Properties of Solid Electrode Surfaces,
https://doi.org/10.1007/978-981-15-7277-7_1
1
Surface Thermodynamics of Solid
Electrode
Abstract Surface thermodynamics is fundamentals for understanding of the electrochemo-mechanical properties of solid electrode surfaces. The concept of surface
phase (or interphase) is explained, and the general equations of surface thermodynamics are derived. Surface stress is the most important thermodynamic parameter
to characterize a solid electrode, since the changes in surface stress are directly
associated with the electro-chemo-mechanical properties. The relationship between
surface stress and surface tension for a solid electrode is discussed to distinguish
from surface tension which characterizes a liquid electrode such as mercury electrode. Furthermore, the electrocapillary curve (surface stress vs. potential or surface
tension vs. potential) for the electrified interface of a solid electrode is derived and
compared with that (surface tension vs. potential) derived for the electrified interface of a liquid electrode. The difference between electrocapillary curves derived for
the electrified interfaces of solid and liquid electrodes is confirmed from the results
obtained experimentally for the electrified interfaces of gold and mercury electrodes.
Keywords Surface thermodynamics · Solid electrode · Surface stress · Surface
tension · Electrocapillary curve
1.1 Introduction
Surface thermodynamics is fundamentals for understanding of the electro-chemomechanical properties of solid electrode surfaces. This chapter deals with surface
thermodynamics of a solid electrode. In the interface region of two phases, the properties vary between those of bulk phase. Surface thermodynamics treats the interface region of two phases as one phase, i.e., surface phase (or interphase). At first,
the explanation for the concept of a surface phase (or interphase) has to precede
the derivation of the general equations of surface thermodynamics. Surface stress
is the most important thermodynamic parameter to characterize a solid electrode
since the changes in surface stress are directly associated with the electro-chemomechanical properties. The derivation of the relationship between surface stress and
surface tension for a solid electrode is indispensable for distinguishing a solid electrode from a liquid electrode such as mercury electrode. The electrocapillary curve
© Springer Nature Singapore Pte Ltd. 2020
M. Seo, Electro-Chemo-Mechanical Properties of Solid Electrode Surfaces,
https://doi.org/10.1007/978-981-15-7277-7_1
1