62
2 Methods for Investigating Electro-Chemo-Mechanical …
Fig. 2.16 Scheme of the experimental setup for a the current–strain response and for b the potential–
strain response in a potentiostatic mode during cyclic elastic deformation [42]. Reproduced from
[42] with permission from the PCCP Owner Societies
In the potential–strain response in a potentiostatic mode (Fig. 2.16b), a delay
resistance of R D ≈ 50k is connected in series with the working electrode, which
leads to an increase in the time constant for potential control at the working electrode,
preventing the potentiostat from compensating the potential change due to the cyclic
strain. On the other hand, the current oscillation due to the cyclic strain becomes
negligible. As a result, the value of
∂E
∂ε
can be directly determined from the straininduced potential change measured by a lock-in amplifier connected between the
working electrode and the reference electrode. Furthermore, in a galvanic mode in
which the current is controlled rather than the potential, the measurement of the
potential–strain response can be achieved without inserting a delay resistance. A
galvanic cycle is performed between the current limits of −1 and 1 µA at a current
scan rate of 10 nA s
−1 under the applied cyclic strain. This mode is directly linked
to a potential change with strain at constant surface charge density since q and ε are
controlled and E is measured. The values of
∂E
∂ε
obtained by three different modes in
Fig. 2.16 coincided each other within a small error in the entire potential range [42].
The above analysis with three different modes is named “dynamic electro-chemomechanical analysis (DECMA)” [42]. As represented by Eq. (1.124) in Sect. 1.8 of
Chap. 1,
∂E
∂ε
q
is equivalent to
∂g
∂q
ε
. The details and typical application results of
DECMA are described in Sect. 3.4.3 of Chap. 3. Moreover, we discuss the equality
between the experimental values of
∂E
∂ε
and
∂g
∂q
, obtained independently by DECMA,
DSA and other methods in Sect. 3.4 of Chap. 3.
2 Methods for Investigating Electro-Chemo-Mechanical …
Fig. 2.16 Scheme of the experimental setup for a the current–strain response and for b the potential–
strain response in a potentiostatic mode during cyclic elastic deformation [42]. Reproduced from
[42] with permission from the PCCP Owner Societies
In the potential–strain response in a potentiostatic mode (Fig. 2.16b), a delay
resistance of R D ≈ 50k is connected in series with the working electrode, which
leads to an increase in the time constant for potential control at the working electrode,
preventing the potentiostat from compensating the potential change due to the cyclic
strain. On the other hand, the current oscillation due to the cyclic strain becomes
negligible. As a result, the value of
∂E
∂ε
can be directly determined from the straininduced potential change measured by a lock-in amplifier connected between the
working electrode and the reference electrode. Furthermore, in a galvanic mode in
which the current is controlled rather than the potential, the measurement of the
potential–strain response can be achieved without inserting a delay resistance. A
galvanic cycle is performed between the current limits of −1 and 1 µA at a current
scan rate of 10 nA s
−1 under the applied cyclic strain. This mode is directly linked
to a potential change with strain at constant surface charge density since q and ε are
controlled and E is measured. The values of
∂E
∂ε
obtained by three different modes in
Fig. 2.16 coincided each other within a small error in the entire potential range [42].
The above analysis with three different modes is named “dynamic electro-chemomechanical analysis (DECMA)” [42]. As represented by Eq. (1.124) in Sect. 1.8 of
Chap. 1,
∂E
∂ε
q
is equivalent to
∂g
∂q
ε
. The details and typical application results of
DECMA are described in Sect. 3.4.3 of Chap. 3. Moreover, we discuss the equality
between the experimental values of
∂E
∂ε
and
∂g
∂q
, obtained independently by DECMA,
DSA and other methods in Sect. 3.4 of Chap. 3.