gets associated with the negatively charged silica surface (–Si–O–Si–), while the
anion gets associated with the inner surface (–Al–OH). Also, the electron-rich ether
group of PEO interacts with the cation, and 3D network formed here supports the ion
migration. The overall impact is the disruption of the crystalline phase due to the
reduction of the crystallinity and hence the low ion pair formation. Another point
mentioned here was that HNT helps in improving the mechanical property with
uniform surface. Also, the zeta potential measurements show increase from negative
to positive, and this evidences the adsorption of ions on the HNT surface. The
thermal stability window was ~400
C. The stress after the addition of HNT
increases from 1.25 MPa to 2.28 MPa with 400% strain and displays good flexibility
of the investigated polymer matrix. The initial discharge capacity of the cell was
1350 mAh g
À1 and with an average value of 745 Æ 21 mAh g
À1 in the
100 discharge–charge cycles, with 87% retention. While at 100
C, the initial
discharge capacity was 1493 mAh g
À1 and was 386 mAh g
À1 after the
400 discharge–charge cycles. It was concluded here that the natural HNT clay
mineral provides the desirable energy density at low cost with improved safety.
Gomari et al. (2017) reported the preparation of nanocomposite solid polymer
electrolyte based on poly(ethylene) oxide (PEO) and lithium perchlorate salt
(LiClO 4 ) with pristine graphene (GnP) or polyethylene glycol-grafted graphene
(FGnP). From FESEM analysis of the nanocomposite, it was concluded that the
rough surface of the pristine PEO changes to smooth on the addition of GnP–FGnP
and suggests the better dispersion of both. Another reason behind this may be the
presence of the hydrogen interactions between the electron-rich group of host
polymer and PEG groups of FGnP. XRD analysis evidences the decrease of the
crystallinity with the addition of GnP, and more decrease was observed for the
FGnP-based polymer nanocomposite. Further evidence provided by the DSC analysis demonstrates no change in the glass transition–melting temperature with a
dispersion of GnP addition, while FGnP dispersion displays shift toward lower
temperature of both glass transition–melting temperature. This may be associated
with the better dispersion of the FGnP as compared to the GnP which enables
sufficient interactions with the PEO. The lowering of the T g indicates an increase
of ion mobility or polymer flexibility owing to the increased free volume. The
polarized optical microscopy also supports both XRD and DSC results as suppression of spherulitic growth in the presence of graphene nanosheets was obtained as
compared to PEO. Further deconvolution of the anion peak in the FTIR spectra
confirmed the increase of free charge carriers with FGnP which participate in
conduction and was attributed to the interaction of PEO as well as additional
coordinating sites provided by PEG. The ionic conductivity was 8.19 Â 10
À6 S
cm
À1 for 0.1 % GnP and 2.53 Â 10
À5 S cm
À1 for 0.5 % FGnP. The increase in the
conductivity was associated with the additional coordinating sites provided by the
PEG, and an ion conduction channel formation supports the faster segmental motion.
The stress–strain curve reports the increase of stiffness and was 74% and 83%
increase for GnP and FGnP at 0.5 wt %, respectively.
Kim et al. (Kim and Park 2007) reported the preparation of the polymer composite electrolyte based on the poly(ethylene oxide) (PEO)–LiClO 4 and different
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A. Arya and A. L. Sharma
anion gets associated with the inner surface (–Al–OH). Also, the electron-rich ether
group of PEO interacts with the cation, and 3D network formed here supports the ion
migration. The overall impact is the disruption of the crystalline phase due to the
reduction of the crystallinity and hence the low ion pair formation. Another point
mentioned here was that HNT helps in improving the mechanical property with
uniform surface. Also, the zeta potential measurements show increase from negative
to positive, and this evidences the adsorption of ions on the HNT surface. The
thermal stability window was ~400
C. The stress after the addition of HNT
increases from 1.25 MPa to 2.28 MPa with 400% strain and displays good flexibility
of the investigated polymer matrix. The initial discharge capacity of the cell was
1350 mAh g
À1 and with an average value of 745 Æ 21 mAh g
À1 in the
100 discharge–charge cycles, with 87% retention. While at 100
C, the initial
discharge capacity was 1493 mAh g
À1 and was 386 mAh g
À1 after the
400 discharge–charge cycles. It was concluded here that the natural HNT clay
mineral provides the desirable energy density at low cost with improved safety.
Gomari et al. (2017) reported the preparation of nanocomposite solid polymer
electrolyte based on poly(ethylene) oxide (PEO) and lithium perchlorate salt
(LiClO 4 ) with pristine graphene (GnP) or polyethylene glycol-grafted graphene
(FGnP). From FESEM analysis of the nanocomposite, it was concluded that the
rough surface of the pristine PEO changes to smooth on the addition of GnP–FGnP
and suggests the better dispersion of both. Another reason behind this may be the
presence of the hydrogen interactions between the electron-rich group of host
polymer and PEG groups of FGnP. XRD analysis evidences the decrease of the
crystallinity with the addition of GnP, and more decrease was observed for the
FGnP-based polymer nanocomposite. Further evidence provided by the DSC analysis demonstrates no change in the glass transition–melting temperature with a
dispersion of GnP addition, while FGnP dispersion displays shift toward lower
temperature of both glass transition–melting temperature. This may be associated
with the better dispersion of the FGnP as compared to the GnP which enables
sufficient interactions with the PEO. The lowering of the T g indicates an increase
of ion mobility or polymer flexibility owing to the increased free volume. The
polarized optical microscopy also supports both XRD and DSC results as suppression of spherulitic growth in the presence of graphene nanosheets was obtained as
compared to PEO. Further deconvolution of the anion peak in the FTIR spectra
confirmed the increase of free charge carriers with FGnP which participate in
conduction and was attributed to the interaction of PEO as well as additional
coordinating sites provided by PEG. The ionic conductivity was 8.19 Â 10
À6 S
cm
À1 for 0.1 % GnP and 2.53 Â 10
À5 S cm
À1 for 0.5 % FGnP. The increase in the
conductivity was associated with the additional coordinating sites provided by the
PEG, and an ion conduction channel formation supports the faster segmental motion.
The stress–strain curve reports the increase of stiffness and was 74% and 83%
increase for GnP and FGnP at 0.5 wt %, respectively.
Kim et al. (Kim and Park 2007) reported the preparation of the polymer composite electrolyte based on the poly(ethylene oxide) (PEO)–LiClO 4 and different
296
A. Arya and A. L. Sharma