crystallinity on the addition of salt was due to the cation coordination with the PEO,
and it alters the polymer chain arrangement and hence the increased segmental
mobility. The addition of nanofiller increases slightly the T g and T m and that may
be due to the cross-linking of the polymer chain while crystallinity reduction is
observed (Kumar et al. 2011). The ionic conductivity increases from 1.00 Â 10
À6 S
cm
À1 to 7.60 Â 10
À4 S cm
À1 (PEO-15 wt. % LiCF 3 SO 3 -20 wt.% DOP) and
8.64 Â 10
À5 S cm
À1 (PEO-15 wt.% LiCF 3 SO 3 -20 wt.%Al 2 O 3 ). This increase in
the conductivity was attributed to increased amorphous phase with the addition of
the nanofiller and the plasticizer. Further mechanical analysis supports both DSC
and the conductivity data. The stress at maximum load, percentage strain at maximum load, and Young’s modulus are 4.4 MPa, 3351%, and 15MPa, respectively, for
the polymer matrix (PEO-15 wt% LiCF 3 SO 3 ). This decrease was attributed to the
disruption of the polymer chain sliding. Further addition of the DOP also lowers the
mechanical properties, and that may be attributed to the effective role of the
plasticizer which lowers the friction (increase the mobility), and it lowers the
mechanical properties (Gondaliya et al. 2013; Ahmed et al. 2010).
Another report using the hybrid nanofiller was by Polu et al. (2017), and it was
based on the effect of polyhedral oligomeric silsesquioxane-polyethylene glycol
(POSS–PEG(n ¼ 4)) nanofiller on the physicochemical and electrochemical properties of PEO–LiDFOB-based nanocomposite solid polymer electrolyte. FESEM
micrographs depict the change of morphology from rough (of PEO) to smoother on
the addition of nanoparticle and may be associated with the complete dissociation of
both salt and nanofiller. XRD analysis confirms the insertion of nanofiller in the
polymer–salt matrix, and enhancement of amorphous content is achieved. Further
DSC analysis confirmed the increased amorphous content and fast segmental
motion. The highest ionic conductivity was 7.28 Â 10
À5 S cm
À1 for 40 wt. % of
the nanoparticle.
This increase may be attributed to the increased free charge carriers and the
increased segmental motion of polymer chains. The increase in temperature
increases the polymer flexibility and hence the increased conductivity that was
evidenced by the reduction of activation energy from 0.594 eV to 0.433 eV with
40 wt. % nanoparticle. The electrochemical stability window of the prepared system
was up to 4.7 V and is in the desirable range. The thermal stability window of the
prepared PNC was ~200
C (Fig. 8.10a). The stress–strain curve evidences the
increase of stress from 0.076 to 0.099 MPa and elongation break from 472 to
516%. This may be due to the key role of nanofiller as a cross-linking center
(Fig. 8.10b). The electrochemical analysis of the cell (Li/PEO:LiDFOB:x wt%
POSS–PEG(x ¼ 0 and 40)/LCO–CBL) shows initial capacity up to 187 mAhg
À1
(for 0 wt. % nanofiller is 158 mAhg
À1 ), and after 50 cycles, discharge capacity was
143 mAhg
À1 (for 0 wt. % nanofiller is 122 mAhg
À1 ) with coulombic efficiency of
99 % at the 25th cycle.
Another report by Wang et al. (2017) explored the role of Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3
(LAGP) on the PEO (LiTFSI) in the suppression of Li dendrite growth. XRD
evidences the decrease of the crystallinity. Figure 8.11a shows the process for the
cell fabrication. Figure 8.11b shows the ion transport mechanism on the addition of
288
A. Arya and A. L. Sharma
and it alters the polymer chain arrangement and hence the increased segmental
mobility. The addition of nanofiller increases slightly the T g and T m and that may
be due to the cross-linking of the polymer chain while crystallinity reduction is
observed (Kumar et al. 2011). The ionic conductivity increases from 1.00 Â 10
À6 S
cm
À1 to 7.60 Â 10
À4 S cm
À1 (PEO-15 wt. % LiCF 3 SO 3 -20 wt.% DOP) and
8.64 Â 10
À5 S cm
À1 (PEO-15 wt.% LiCF 3 SO 3 -20 wt.%Al 2 O 3 ). This increase in
the conductivity was attributed to increased amorphous phase with the addition of
the nanofiller and the plasticizer. Further mechanical analysis supports both DSC
and the conductivity data. The stress at maximum load, percentage strain at maximum load, and Young’s modulus are 4.4 MPa, 3351%, and 15MPa, respectively, for
the polymer matrix (PEO-15 wt% LiCF 3 SO 3 ). This decrease was attributed to the
disruption of the polymer chain sliding. Further addition of the DOP also lowers the
mechanical properties, and that may be attributed to the effective role of the
plasticizer which lowers the friction (increase the mobility), and it lowers the
mechanical properties (Gondaliya et al. 2013; Ahmed et al. 2010).
Another report using the hybrid nanofiller was by Polu et al. (2017), and it was
based on the effect of polyhedral oligomeric silsesquioxane-polyethylene glycol
(POSS–PEG(n ¼ 4)) nanofiller on the physicochemical and electrochemical properties of PEO–LiDFOB-based nanocomposite solid polymer electrolyte. FESEM
micrographs depict the change of morphology from rough (of PEO) to smoother on
the addition of nanoparticle and may be associated with the complete dissociation of
both salt and nanofiller. XRD analysis confirms the insertion of nanofiller in the
polymer–salt matrix, and enhancement of amorphous content is achieved. Further
DSC analysis confirmed the increased amorphous content and fast segmental
motion. The highest ionic conductivity was 7.28 Â 10
À5 S cm
À1 for 40 wt. % of
the nanoparticle.
This increase may be attributed to the increased free charge carriers and the
increased segmental motion of polymer chains. The increase in temperature
increases the polymer flexibility and hence the increased conductivity that was
evidenced by the reduction of activation energy from 0.594 eV to 0.433 eV with
40 wt. % nanoparticle. The electrochemical stability window of the prepared system
was up to 4.7 V and is in the desirable range. The thermal stability window of the
prepared PNC was ~200
C (Fig. 8.10a). The stress–strain curve evidences the
increase of stress from 0.076 to 0.099 MPa and elongation break from 472 to
516%. This may be due to the key role of nanofiller as a cross-linking center
(Fig. 8.10b). The electrochemical analysis of the cell (Li/PEO:LiDFOB:x wt%
POSS–PEG(x ¼ 0 and 40)/LCO–CBL) shows initial capacity up to 187 mAhg
À1
(for 0 wt. % nanofiller is 158 mAhg
À1 ), and after 50 cycles, discharge capacity was
143 mAhg
À1 (for 0 wt. % nanofiller is 122 mAhg
À1 ) with coulombic efficiency of
99 % at the 25th cycle.
Another report by Wang et al. (2017) explored the role of Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3
(LAGP) on the PEO (LiTFSI) in the suppression of Li dendrite growth. XRD
evidences the decrease of the crystallinity. Figure 8.11a shows the process for the
cell fabrication. Figure 8.11b shows the ion transport mechanism on the addition of
288
A. Arya and A. L. Sharma