4.2 Electrochemistry
167
Table 4.2 Comparison of
energies 1 of neutral and
cationic polymers 1 and 2 in
Fig. 4.17
Polymer
Charge per unit cell
E L–H
2
1
Neutral
–
+3
3.1
+6
11.8
2
Neutral
–
+3
3.7
+6
19.6
Reprinted from Ito et at. 2009. Copyright 2009, with permission
from Elsevier
1 Based on the HF and UHF/CO/6-21G calculations
2 In eV: Positive value signifies the stability of the higher spin state
4.2 Electrochemistry
The electrochemical process is of much importance both scientifically and technologically. In the electrochemical process, the central idea is based on the redox behaviors
of materials and the electron transfer accompanied by this process. For a considerably long time, however, ambiguity had been remaining in many phenomena as far
as starting from the conventional understanding through classical electrochemistry.
This is partly because that the electrochemical process is not based on simple redox
process but consists of a collection of various complicated interfacial problems such
as those between the electrodes and the medium of electrons or ions, actual shape and
behavior of ions in the electrolyte solution, actual pictures for ion migration, effective
electron transfer, participation of irradiated light, and many other factors. Hence the
attempts toward the total understanding of these ought to encounter various difficulties. Fortunately, in recent years, various observation techniques such as Raman
spectroscopy, photoemission spectroscopy (PES), atomic force microscopy (AFM),
soft X-ray emission spectroscopy (SXES), and so on have been developed to directly
check the electrochemical events. The theoretical calculation could also become
one of these to assist the understandings of some complicated events involved in
electrochemical processes in many ways.
In this section, a couple of examples studied by theoretical calculations are elucidated to help understanding how it works in the actual examples in electrochemistry.
4.2.1 Solvation of Metallic Cation
It is well known that, in the rechargeable lithium-ion battery (LIB), Li
+ ions migrate
from the positive electrode to the negative electrode in the charging process, and
to the opposite direction in the discharging process through the electrolyte solution
consisting of organic solvent and supporting electrolyte as illustrated in Fig. 4.19.
167
Table 4.2 Comparison of
energies 1 of neutral and
cationic polymers 1 and 2 in
Fig. 4.17
Polymer
Charge per unit cell
E L–H
2
1
Neutral
–
+3
3.1
+6
11.8
2
Neutral
–
+3
3.7
+6
19.6
Reprinted from Ito et at. 2009. Copyright 2009, with permission
from Elsevier
1 Based on the HF and UHF/CO/6-21G calculations
2 In eV: Positive value signifies the stability of the higher spin state
4.2 Electrochemistry
The electrochemical process is of much importance both scientifically and technologically. In the electrochemical process, the central idea is based on the redox behaviors
of materials and the electron transfer accompanied by this process. For a considerably long time, however, ambiguity had been remaining in many phenomena as far
as starting from the conventional understanding through classical electrochemistry.
This is partly because that the electrochemical process is not based on simple redox
process but consists of a collection of various complicated interfacial problems such
as those between the electrodes and the medium of electrons or ions, actual shape and
behavior of ions in the electrolyte solution, actual pictures for ion migration, effective
electron transfer, participation of irradiated light, and many other factors. Hence the
attempts toward the total understanding of these ought to encounter various difficulties. Fortunately, in recent years, various observation techniques such as Raman
spectroscopy, photoemission spectroscopy (PES), atomic force microscopy (AFM),
soft X-ray emission spectroscopy (SXES), and so on have been developed to directly
check the electrochemical events. The theoretical calculation could also become
one of these to assist the understandings of some complicated events involved in
electrochemical processes in many ways.
In this section, a couple of examples studied by theoretical calculations are elucidated to help understanding how it works in the actual examples in electrochemistry.
4.2.1 Solvation of Metallic Cation
It is well known that, in the rechargeable lithium-ion battery (LIB), Li
+ ions migrate
from the positive electrode to the negative electrode in the charging process, and
to the opposite direction in the discharging process through the electrolyte solution
consisting of organic solvent and supporting electrolyte as illustrated in Fig. 4.19.