interaction of cation with ether group of PEO owing to the clay interaction with ether
group.
Ma et al. (2016) prepared the composite solid polymer electrolyte (CSPE) based
on montmorillonite (MMT) nanoclay fillers, lithium-bis(trifluoromethanesulfonyl)
(LiTFSI), polyvinylidene difluoride (PVDF), and polyvinyl alcohol (PVA) copolymer by the casting method. FESEM analysis evidences the porous structure that will
be beneficial for the cation transport. Further, the addition of MMT to blend polymer
matrix lowers the crystallinity and indicates the increased amorphous content.
The ionic conductivity also increases with the addition of MMT, and highest
conductivity was 4.31 Â 10
À4 S cm
À1 for 4 wt. % clay content. The increase in
the conductivity value was due to the high surface area of the nanoclay which
increases in the free volume and the amorphous content. These together lead to
smoother ion transport and hence high ionic conductivity. The activation energy
value decreases with the addition of MMT from 26.46 kJ to 16.22 kJ and evidences
the faster ion migration. The cation transference number increased from 0.29 to 0.40
with the addition of the MMT (Fig. 8.17b). The displacement load curve evidenced
the increase of the tensile strength from 1.17 MPa to 2.24 MPa with the addition of
clay and is attributed to the improved stability. The Li–CSPE–LiFePO 4 cells show
pretty high specific discharge capacity above 123 mAhg
À1 along with a coulombic
efficiency of 97.1% after 100 cycles.
Mohapatra et al. (2009) reported the preparation of the PEO–LiClO 4 -based composite polymer electrolyte with organo-modified montmorillonite clay using solution
cast technique. XRD analysis evidenced the complex formation, and shift in the peak
of the hot matrix shows the effective role played by clay. The decrease of the peak
intensity evidences the reduction of the crystallinity due to the polymer and the
nanoclay interaction. The d-spacing was almost the same in all systems, while the
crystallite size decreases, and clay gallery width was maximum for the 10 wt. % clay
content (9 Å). Further, the polymer–salt intercalation in the clay galleries was
evidenced and was due to the dipolar interaction. It was concluded from the XRD
that the prepared PNCE films have a multiphase combination of crystalline and
amorphous PS phases, an amorphous phase boundary, crystalline clay, and amorphous
PS inside the clay galleries at the interface of the clay layers and PS matrix. Further,
TEM analysis provides strong evidence of the intercalation along with exfoliation at
low clay content. At very high clay content (>20 wt. %), clay cluster formation was
reported. DSC analysis displayed the lowering of the glass transition temperature (T g )
owing to the enhanced flexibility assisted by intercalation on nanocomposite formation. The highest ionic conductivity was 6.48 Â 10
À5 S cm
À1 for 10 wt. % clay content
(at 30
C). TGA analysis shows the thermal stability of the composite polymer
electrolyte up to 300
C and is sufficient for the application purpose (Fig. 8.17c).
The cation transference number was 0.50 at 2 wt. % clay content. And voltage stability
window was about 3 V. The thermal stability was improved after the polymer chain
intercalation inside clay galleries. This may be attributed to the barrier role played by
clay layers which prevent the decomposition of the polymer–salt complex. Another
reason may be the catalytic effect in which the clay layers accumulated all heat and
prevent the decomposition of the polymer slats system.
298
A. Arya and A. L. Sharma
group.
Ma et al. (2016) prepared the composite solid polymer electrolyte (CSPE) based
on montmorillonite (MMT) nanoclay fillers, lithium-bis(trifluoromethanesulfonyl)
(LiTFSI), polyvinylidene difluoride (PVDF), and polyvinyl alcohol (PVA) copolymer by the casting method. FESEM analysis evidences the porous structure that will
be beneficial for the cation transport. Further, the addition of MMT to blend polymer
matrix lowers the crystallinity and indicates the increased amorphous content.
The ionic conductivity also increases with the addition of MMT, and highest
conductivity was 4.31 Â 10
À4 S cm
À1 for 4 wt. % clay content. The increase in
the conductivity value was due to the high surface area of the nanoclay which
increases in the free volume and the amorphous content. These together lead to
smoother ion transport and hence high ionic conductivity. The activation energy
value decreases with the addition of MMT from 26.46 kJ to 16.22 kJ and evidences
the faster ion migration. The cation transference number increased from 0.29 to 0.40
with the addition of the MMT (Fig. 8.17b). The displacement load curve evidenced
the increase of the tensile strength from 1.17 MPa to 2.24 MPa with the addition of
clay and is attributed to the improved stability. The Li–CSPE–LiFePO 4 cells show
pretty high specific discharge capacity above 123 mAhg
À1 along with a coulombic
efficiency of 97.1% after 100 cycles.
Mohapatra et al. (2009) reported the preparation of the PEO–LiClO 4 -based composite polymer electrolyte with organo-modified montmorillonite clay using solution
cast technique. XRD analysis evidenced the complex formation, and shift in the peak
of the hot matrix shows the effective role played by clay. The decrease of the peak
intensity evidences the reduction of the crystallinity due to the polymer and the
nanoclay interaction. The d-spacing was almost the same in all systems, while the
crystallite size decreases, and clay gallery width was maximum for the 10 wt. % clay
content (9 Å). Further, the polymer–salt intercalation in the clay galleries was
evidenced and was due to the dipolar interaction. It was concluded from the XRD
that the prepared PNCE films have a multiphase combination of crystalline and
amorphous PS phases, an amorphous phase boundary, crystalline clay, and amorphous
PS inside the clay galleries at the interface of the clay layers and PS matrix. Further,
TEM analysis provides strong evidence of the intercalation along with exfoliation at
low clay content. At very high clay content (>20 wt. %), clay cluster formation was
reported. DSC analysis displayed the lowering of the glass transition temperature (T g )
owing to the enhanced flexibility assisted by intercalation on nanocomposite formation. The highest ionic conductivity was 6.48 Â 10
À5 S cm
À1 for 10 wt. % clay content
(at 30
C). TGA analysis shows the thermal stability of the composite polymer
electrolyte up to 300
C and is sufficient for the application purpose (Fig. 8.17c).
The cation transference number was 0.50 at 2 wt. % clay content. And voltage stability
window was about 3 V. The thermal stability was improved after the polymer chain
intercalation inside clay galleries. This may be attributed to the barrier role played by
clay layers which prevent the decomposition of the polymer–salt complex. Another
reason may be the catalytic effect in which the clay layers accumulated all heat and
prevent the decomposition of the polymer slats system.
298
A. Arya and A. L. Sharma