Structural,transport,morphological,and thermal studies of nano barium titanate–incorporated magnesium ion conducting solid polymer electrolytes

Abstract

A new series of nanocomposite polymer electrolytes (NCPEs) was prepared using poly(vinylidene fluoride–co–hexafluoro propylene) P(VdF-HFP) as polymer, magnesium triflate (MgTr) as salt and nano-sized barium titanate (BaTiO₃) (<100 nm) as nanofiller via traditional solution casting technique. Decrease in crystalline nature of the samples due to the incorporation of nano BaTiO₃ was revealed through X-ray diffraction (XRD) analysis. From AC impedance spectroscopy, maximum conductivity of 4.11 × 10⁻⁴ Scm⁻¹ was attained for the addition of 6 wt% of nano BaTiO₃ to the P(VdF-HFP)/MgTr matrix. Dielectric studies were found to be in accordance with the ionic conductivity studies. For the most highly conducting sample, a greater number of mountain valley pattern was observed from Atomic Force Microscopy (AFM) analysis. Thermal stability of the sample, P(VdF-HFP)/MgTr/BaTiO₃ (6 wt%) (which possessed maximum ionic conductivity) was observed through TG/differential thermal analysis studies. All these results suggested that these materials are favorable and find application in practical electrochemical devices.

Keywords

Solvent casting technique impedance spectroscopy ionic conductivity thermal stability dielectric modulus analysis relaxation time

Introduction

Solid polymer electrolytes (SPEs) have been widely used because they possess unique combined properties such as ionic conductivity and good mechanical strength leads to use in solid-state devices including batteries, electrochromic displays, supercapacitors, and smart windows^{1, 2} Up-to-date researchers focused their attention in developing rechargeable batteries based on lithium ion, since it possess high specific energy capacity and cycling stability.³ But, due to its high cost and less abundance in nature, it could not be used for widespread applications.⁴ Hence, a search for alternative resources instead of Li ion is needed.

In the recent past, magnesium ion–based polymer electrolyte system has attained a better interest because the performance capabilities shown by them are similar to that of lithium based rechargeable batteries.⁵ Also, the secondary magnesium batteries are quite fascinating compared with lithium batteries because of the following advantages: (i) the ionic radius of Li⁺ is 68 pm, whereas the ionic radius Mg²⁺ is 65 pm. Therefore, Li⁺ can be replaced by Mg²⁺;⁶ (ii) the magnesium metal is more stable to oxygen and humid atmospheres, and thus, it can be handled more easily; (iii) plenty in nature; (iv) lower cost than that of lithium; (v) considerable negative electrode potential; (vi) the charge density is high; (vii) melting point is high (649 °C); and (vii) less toxic, and hence, it is easy to handle and dispose.^7–10 But, the development of polymer electrolyte for the rechargeable magnesium batteries is still in search. Due to the above said appealing characteristics of magnesium, magnesium triflate (MgTr) is chosen as an electrolyte for the present work.

For the present work, poly(vinylidene fluoride–co–hexafluoro propylene) (P(Vdf-HFP)) is chosen as a polymer host, as it possess less crystallinity when compared to PVdF.¹¹ In addition to this, the value of dielectric constant of P(Vdf-HFP) is (ε = 8.4); hence, it could solvate more salt which result in an augmentation of ionic conductivity of the polymer electrolyte.¹²

Earlier investigators suggested that the addition of nanofillers such as SrTiO₃, TiO₂, MgO, yttria-stabilized zirconia, sepolite, and BaTiO₃ to polymer electrolytes can improve (i) its ionic conductivity and (ii) its mechanical stability.^13,14,15 Based on these facts, to enhance the ionic conductivity of polymer electrolyte, nano-sized barium titanate (BaTiO₃) is used here. The filler, BaTiO₃ is used as a material for capacitor applications, as it has a high dielectric constant (10³–10⁵). Further, it possesses ferroelectric domain. The presence of ferroelectric domain and high dielectric nature of BaTiO₃ facilitate the electrolyte dissociation into charged species. Also, more amorphous phase is produced; therefore, the conductivity of the samples can be boosted.¹⁵

For the current work, an effort has been made to prepare P(Vdf-HFP)/MgTr samples with different concentrations of nano BaTiO₃, and the influence of content of the BaTiO₃ filler on the ionic conductivity, structural, dielectric, morphological, and thermal properties are examined which have not been yet explored. Thus, this work paves a way for more work in magnesium based polymer electrolytes in near future.

Experimental techniques

Materials

Polymer, poly(vinylidene fluoride–hexafluoro propylene) (P(VdF-HFP)) (M_w ∼ 130,000 gmol⁻¹) and the electrolyte, magnesium triflate (MgTr) were purchased from Sigma-Aldrich, USA. Nano-sized barium titanate (BaTiO₃) (<100 nm) was obtained from Alfa Aeson, India. Acetonitrile was used as a solvent, and the same was procured from Merck, India. These chemicals were used without any further purification.

Sample preparation technique

The samples P(VdF-HFP)/MgTr with different concentrations of BaTiO₃(2 wt% to 10 wt%) in steps of 2 wt% were synthesized by conventional solution casting technique. The ratio of polymer and salt was used here was P(VdF-HFP) (70 wt%)/MgTr (30 wt%) as it was found to be an optimized one for getting stable SPEs. The polymer and the salt were dissolved by adding in sequence to the solvent acetonitrile and stirred well for 24 h. Now, the nanofiller BaTiO₃ (<100 nm) was added to the polymer electrolyte solution and stirred well until the solution was homogenously mixed. Then, these NCPE solutions were poured in a Petri dish and kept inside a vacuum oven at 60 °C for 24 h. Using this technique, mechanically stable and free standing films were harvested. The sample preparation is illustrated in Figure 1.

Figure 1.

Schematic representation of sample preparation.

Characterization and measurement

The prepared samples were subjected to AC impedance measurement to determine ionic conductivity. AC impedance measurement was carried out using PSM 1735 impedance analyzer which was purchased from Newton’s 4th Ltd, UK. Here in, we have used two stainless steel (SS) blocking electrodes. The prepared samples were placed between these two electrodes. The experiment was performed in a wide frequency range of 1 Hz–10 MHz and with a signal amplitude of 2 mV.

The total ionic transference number of the prepared samples was analyzed by means of Wagner’s polarization technique. In this work, the cell was polarized by applying a constant potential to a cell configuration of SS electrode/sample/SS electrode. As a result, current is produced, which was then examined as a function of time with the impedance analyzer. Using this technique, the total ionic transference number was calculated using the following formula

t_{ion} = \frac{I_{o} - I_{s}}{I_{o}}

(1)

where I_o and I_s and are the initial and saturation currents, respectively.

X-ray diffractograms of the nanocomposite polymer electrolytes (NCPEs) were obtained using an X’pert PRO-PANalytical diffractometer with Cu-K_α radiation (wavelength, λ = 0.154 nm) with a scanning range between 2θ = 10^ο and 80^ο at ambient temperature.

The thermal stability of the sample was analyzed using thermo-gravimetric analyzer whose model is 2950 under N₂ atmosphere. The temperature range used here was from room temperature to 700 C in steps of 20 C min⁻¹. Atomic Force Microscopy (AFM) analysis was carried out using Agilent Pico LE microscope instrument.

Results and discussion

AC impedance analysis

Impedance spectra for the prepared P(VdF-HFP)/MgTr system and P(VdF-HFP)/MgTr with different contents of BaTiO₃ are presented in Figure 2. It possesses a semicircle in the higher frequency side, which arises because of the bulk effect of the electrolyte and the linear region in the lower frequency range, ascribed to the effect of the blocking electrodes. The ionic conductivity of BaTiO₃-added polymer electrolyte system is calculated with the help of the following equation

σ = \frac{l}{R_{b} A}

(2)

where

l

represents the thickness of the prepared films,

A

is the area of the SS electrode, and

R_{b}

is the bulk resistance. From the intercept of high frequency semicircle on the Z^’ axis, the values of bulk resistance can be obtained.

Figure 2.

AC impedance plot for the nano BaTiO₃–incorporated P(VdF-HFP)/MgTr system.

The values of ionic conductivity of the prepared systems are estimated using equation (2) and they are listed in Table 1. For P(VdF-HFP)/MgTr system, ionic conductivity value is to be 5.7 × 10⁻⁵ Scm⁻¹ at room temperature. These values increased gradually when nano BaTiO₃ was incorporated into the P(VdF-HFP)/MgTr system. Maximum ionic conductivity of 4.1 × 10⁻⁴ Scm⁻¹ is attained for the addition of 6 wt% nano BaTiO₃. This increase in the value of ionic conductivity is due to the fact, that there exists a stronger interaction between nano BaTiO₃ and polymer chain, which results in the establishment of amorphous region.¹⁴

Table 1.

Values of ionic conductivity for P(VdF-HFP)/MgTr/BaTiO₃ samples.

Concentrations of BaTiO₃ (wt %)	Ionic conductivity (Scm⁻¹)
0	5.7 × 10⁻⁵
2	6.0 × 10⁻⁵
4	9.8 × 10⁻⁵
6	4.1 × 10⁻⁴
8	8.5 × 10⁻⁵
10	1.4 × 10⁻⁵

The enhancement in ionic conductivity can be explicated via Lewis acid–base interactions as follows. There exists a competition between the strong acidic surface of nano BaTiO₃ and Mg²⁺ cation, so as to interact with the fluorine atom of the polymer P(VdF-HFP). It in turn reduces the coupling of the fluorine and the cation (Mg²⁺), thus supporting the dissociation of the electrolyte and hence the ionic conductivity. Similar results were reported by earlier investigators.^15,16

Earlier researchers^15,16 reported that the augmentation of ionic conductivity is not only due to the Lewis acid–base interaction, but also due to the creation of conductive layer in the vicinity region of the filler particle. Such a conductive layer paves the way for the Mg²⁺ ion to get migrate. In addition, it is also to be noted that BaTiO₃ is a ferroelectric filler, and hence, it possesses spontaneous polarization. This in turn also enables the solvation of the electrolyte MgTr,¹⁵ and therefore, the ionic conductivity is improved.

The value of ionic conductivity gets decreased for the system with more than 6 wt% of nano BaTiO₃. It is due to the fact that the higher concentration of filler blocks the ionic movement, and hence, the system does not conduct the ions. Such a blocking effect is due to the discontinuities in phases which overwhelm the polymer segmental motion and the ion mobility.^17,18

Transference number analysis

To validate the AC impedance results, the values of total ionic transference number (t_ion) play a vital role. Wagner’s polarization technique is used to determine t_ion. For this experiment, a fixed dc voltage is applied across SS electrode/sample/SS electrode. As a result, dc current is produced and it is monitored with the function of time. Using this technique, we have estimated the values of t_ion for P(VdF-HFP)/MgTr/BaTiO₃ system and the same are given in Table 2. Figure 3(a)–(e) shows the graph of the polarization current versus time for the P(VdF-HFP)/MgTr/BaTiO₃ system. From these figures, it is seen that the current decreases continuously until a stable state (saturation) is attained. The fall in the current from the initial state (I_o) is due to the species migration in the polarization process, which greatly suppresses the ion motion.¹⁹ For P(VdF-HFP)/MgTr/2wt% of BaTiO₃ system, the value of t_ion is 0.761. The value of t_ion is further enhanced to 0.903 for 6 wt% BaTiO₃-incorporated P(VdF-HFP)/MgTr system. These values revealed that the transportation of charge in the prepared systems is mainly because of ions. Further, the improved t_ion value of 0.903 for 6 wt% BaTiO₃/P(VdF-HFP)/MgTr system is due to the creation of favorable pathways in the polymer electrolyte for better movement of the Mg²⁺ ions through the greater interaction of nanofiller BaTiO₃ and P(VdF-HFP).¹⁹

Table 2.

Values of transport number for the prepared samples.

Concentrations of BaTiO₃ (wt %)	t_ion
2	0.761
4	0.741
6	0.903
8	0.841
10	0.814

Figure 3.

Variation of polarization current as a function of time under a constant voltage for a) 2wt % of BaTiO₃, b) 4wt % of BaTiO₃, c) 6wt % of BaTiO₃, d) 8wt % of BaTiO₃, e) 10wt % of BaTiO₃-added P(VdF-HFP)/MgTr systems.

X-ray diffraction analysis

Figure 4(a)–(e) represents the X-ray diffraction (XRD) pattern of P(VDF-HFP), MgTr, P(VDF-HFP)/MgTr, nano BaTiO₃ and P(VDF-HFP)/MgTr/BaTiO₃(6 wt%) system, respectively. Figure 4(a) shows the X-ray diffractogram of P(VDF-HFP). The appearance of diffraction peaks at 2 $θ = 18 °$ , 20°, 27°, and 37° confirms the presence of PVDF units in the co-polymer P(VDF-HFP) and is compared with earlier report.²⁰

Figure 4.

X-ray diffractograms of (a) P(VDF-HFP), (b) MgTr, (c) P(VDF-HFP)/MgTr, (d) nano BaTiO₃, (e) P(VDF-HFP)/MgTr/BaTiO₃ (6 wt%)–added system.

The appearance of diffraction peaks in Figure 4(b) and (d) suggests that the salt and the filler BaTiO₃ used here are of highly crystalline. It is observed from Figure 4(c) (P(VDF-HFP)/Mg(CF₃SO₃)₂ system) that the amorphous nature of the polymer P(VDF-HFP) is greatly enhanced after the addition of Mg(CF₃SO₃)₂. In addition, the characteristics diffraction peaks of Mg(CF₃SO₃)₂ are found to be absent. This implies that the salt Mg(CF₃SO₃)₂ is solvated well in P(VDF-HFP) matrix, and hence, the P(VdF-HFP)/MgTr complex is formed.

It is seen that the intensities of the diffraction peaks of BaTiO₃ get broadened and decreased (as in Figure 4(e)), when it is incorporated into the polymer electrolyte matrix at a concentration of 6 wt% (possessed maximum ionic conductivity). This proposes that the inert filler BaTiO₃ promotes a change in the re-organization of the polymer chain and assists higher ionic conduction.²⁰ Moreover, the establishment of amorphous phase through Lewis acid–base interaction is also acknowledged through the XRD pattern. It in turn releases of Mg²⁺ ion and hence enhanced the ionic conductivity. These results divulge that the nanofiller added acted as a “Solid Plasticizer.”

Dielectric analysis

The real and imaginary parts of the dielectrics (ε^′,ε^″) can be expressed by

ε^{'} = \frac{- Z^{″}}{ω C_{o} (Z^{' 2} + Z^{″ 2})}

(4)

ε^{″} = \frac{Z^{'}}{ω C_{o} (Z^{' 2} + Z^{″ 2})}

(5)

where Z^′ and Z^″ indicate the real and imaginary impedances; ω is the angular frequency; C_o corresponds to the capacitance due to vacuum of any electrode configurations; ε^′ and ε^″ are the real and imaginary permittivities, respectively.

Figures 5(a) and (b) show the frequency dependence of the dielectric constants ε^′ and ε^″ for different concentrations of nano BaTiO₃–added P(VdF-HFP)/MgTr system at ambient temperature. Variation of ε^′ and ε^″ values against the concentration of BaTiO₃ corroborates the variation trend of ionic conductivity.

Figure 5.

Variation of the (a) dielectric permittivity ?′ versus logω, (b) dielectric loss ?′′ versus log ω for P(VdF-HFP)/MgTr/BaTiO3 system at room temperature.

From these figures, the magnitude of dielectric constant (ε^′) and dielectric loss (ε^″) are found to be large in the lower frequency region. However, these values get decreased with increase of frequency and reached saturation in the higher frequency region. This is because, in the lower frequency region, dipoles in the P(VdF-HFP) may align more easily in a faster manner toward the applied fields direction. This event does not happen in the higher frequency side as there is no enough time for the dipoles to align along the direction of the field applied;²⁰ hence, ε^′ and ε^″ values are low.

As observed in ionic conductivity, the values of ε^′ and ε^″ are seen to be high for 6 wt% nano BaTiO₃–added P(VdF-HFP)/MgTr system while compared with other concentrations of BaTiO₃ which implies there exists only a small electrostatic attraction between the mobile ions, and hence, the probability of mobile ions in the free states becomes greater.²⁰

Modulus analysis

Figure 6(a) and (b) indicate the variation of M′ and M^″ versus logω for nano BaTiO₃–added P(VdF-HFP)/MgTr system.

Figure 6.

Variation of the (a) real part of electric modulus M^′ versus log ω, (b) imaginary part of electric modulus M^′’ versus log ω for P(VdF-HFP)/MgTr/BaTiO3 system at room temperature.

In these plots, at low frequency side, a long tail is observed. It is due to the presence of large capacitance which are accompanied by the electrodes. This substantiates that the materials are of non-Debye type. It is seen from these figures that the spectrum shape is found to be same for all BaTiO₃ contents. But, the position of the peak is shifted to higher frequency side for the addition of 6 wt% of BaTiO₃ system, whereas the position of the peak is found to be in lower frequency side for the other concentrations of BaTiO₃. It assures that the charge carrier hopping is higher for the said BaTiO₃ concentration than any other concentrations.¹³

Loss tangent studies

Loss tangent spectra for P(VdF-HFP)/MgTr system with different concentrations of BaTiO₃ are given in Figure 7. These spectra show a broad peak at a distinctive frequency which confirms the existence of dipole relaxation in the prepared system. The peak maxima of loss tangent for 6 wt% of BaTiO₃-added system exhibited a small shift toward the higher frequency, whereas the others in the low frequency side. Such shifting of peak toward the high frequency side is a consequence of fast segmental motion of the free ions, whereas the peak shift toward low frequency side is a result of constrained segmental motion coupled with the ion.²¹

Figure 7.

Loss tangent spectra for P(VdF-HFP)/MgTr system with different concentrations of BaTiO₃.

Tangent loss can be expressed by the following equation

\tan δ = \frac{ε^{″}}{ε^{'}}

(6)

The values of relaxation time (τ) are obtained by plotting tan δ as a function of logω and using the relation ωτ = 1, where τ is the relaxation time and ω is the angular frequency of the applied signal.

For the long-chain polymers, the bond rotation is favorable only at low frequencies, that is, higher is the relaxation time. But the presence of filler increases the disorder within the polymer network, and thus, the rotation becomes feasible; making a shift toward higher frequency side means a shorter relaxation time. The presence of the appropriate concentration of filler particles makes the polymer chain very flexible to allow any conformational changes, and hence, the relaxation occurs at a higher frequency in conjunction with smaller relaxation time. Therefore, it can be concluded that the doping of BaTiO₃ changes the amorphicity and produces relatively fast segmental motion coupled with mobile ion.

The relaxation parameter for the said systems given in Table 3 shows that the value of the relaxation time is less for P(VdF-HFP)/MgTr with 6 wt% of BaTiO₃ system when it is correlated with the rest of the contents of nano BaTiO₃ and supports the conductivity studies.

Table 3.

Values of relaxation time (τ) for the prepared samples.

Concentrations of BaTiO₃ (wt %)	Relaxation time (τ) (m sec)
0	7.328
2	5.902
4	6.666
6	4.786
8	6.081
10	6.339

Atomic force microscopy analysis

Figures 8(a) and (b) illustrate the 3D-AFM images of P(VdF-HFP)/MgTr and P(VdF-HFP)/MgTr with 6 wt% of nano BaTiO₃ systems. The system P(VdF-HFP)/MgTr shows a mountain valley pattern with a roughness (root mean square (RMS)) value of 85.80 nm. Similar mountain valley pattern also appeared for the nano BaTiO₃ (6 wt%)–added P(VdF-HFP)/MgTr system (Figure 8(b)), but the number of mountains and valleys is more compared with filler-free one. Further, the roughness value is increased to 116 nm, which is being higher than that of the previous one. This increase in roughness value for the nano BaTiO₃–added one inferred that the filler gets well dispersed in the P(VdF-HFP)/MgTr matrix.²² As a consequence, the polymer electrolyte undergoes as a structural modification as observed in XRD studies and supports the transport of Mg²⁺ ions through P(VdF-HFP) matrix.

Figure 8.

Atomic force microscopy images of (a) P(VdF-HFP)/MgTr system, (b) P(VdF-HFP)/MgTr system/BaTiO₃ (6 wt%) system.

TG/differential thermal analysis Studies

Figure 9 represents the TG/differential thermal analysis (DTA) curves of the sample P(VdF-HFP)/MgTr with 6 wt% of nano BaTiO₃. It is noticed from DTA curve, that the sample shows an endothermic peak at low temperature at around 127 °C. This is due to the moisture’s removal or solvent residues present in the film. Further, the DTA curve shows a broad endothermic peak at 340 °C. At this point, the theromogravimetric analysis traces exhibited a weight loss of about 61%. At this stage, the side chain of the polymer may degrade and hence weight loss is more.^23,24,25 The decomposition of the sample completes beyond 450 °C. Thus, the appearance of the peak in DTA is well in accordance with the thermogravimetric analysis result.

Figure 9.

TG/DTA thermogram of P(VdF-HFP)/MgTr system/BaTiO₃ (6 wt%) system.

Conclusions

Nanocomposite polymer electrolytes (NCPEs) composed of P(VdF-HFP)/MgTr with various concentrations of BaTiO₃ nanofiller were successfully prepared by conventional solvent casting technique. XRD studies revealed that the nano BaTiO₃ promotes the structural modification in the P(VdF-HFP)/MgTr matrix. Values of ionic conductivity increased with the rise in filler concentration, and the system with 6 wt% of BaTiO₃ showed a maximum ionic conductivity of 4.110 × 10⁻⁴ Scm⁻¹ at room temperature. A low relaxation time was obtained for P(VdF-HFP)/MgTr with 6 wt% of nano BaTiO₃ system which possessed maximum ionic conductivity. A significant change in RMS values was attained through AFM studies. From TG/DTA analyses, the maximum ionic conducting sample was found to be stable up to 340 °C. All these results clearly illustrate that the prepared NCPE met the prerequisite properties; therefore, it can be used as a separator in energy storage devices.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Jayanthi S

References

Zhang

Gamble

Ainsworth

, et al. Alkali metal crystalline polymer electrolytes. Nat Mater 2009; 8: 580–584.

Kim

Son

Mukherjee

, et al. A review of lithium and non-lithium based solid state batteries. J Power Sourc 2015; 282: 299–322.

Weppner

. Secondary batteries - lithium rechargeable systems | all-solid state battery. In: Garche

(ed). Encyclopedia of electrochemical power sources. Amsterdam: Elsevier 2009, pp. 162–168.

Ni’mah

Cheng

M-Y

Cheng

, et al. Solid-state polymer nanocomposite electrolyte of TiO2/PEO/NaClO4 for sodium ion batteries. J Power Sourc 2015; 278: 375–381.

Pandey

Agrawal

Hashmi

. Electrical and electrochemical properties of magnesium ion conducting composite gel polymer electrolytes. J Phys D: Appl Phys 2010; 43: 255501.

Foot

. Principles and prospects of high-energy magnesium-ion batteries. Sci Prog 2015; 98: 264–275.

N-J

Kim

M-K

Kang

S-W

, et al. The influence of the cations of salts on the electrochemical stability of a solid polymer electrolyte based on segmented poly(ether urethane). Physica Scripta 2010; T139: 014035.

Aurbach

Suresh

Levi

, et al. Progress in rechargeable magnesium battery technology. Adv Mater 2007; 19: 4260–4267.

Mitelman

Levi

Lancry

, et al. New cathode materials for rechargeable Mg batteries: fast Mg ion transport and reversible copper extrusion in CuyMO6S8 compounds. Chem Commun 2007; 41: 4212–4214.

10.

Yuan

Jiao

Cao

, et al. Development of magnesium-insertion positive electrode for rechargeable magnesium batteries. J Mater Sci Technol 2004; 20: 41–45.

11.

Zhang

, et al. Effects of the porous structure on conductivity of nanocomposite polymer electrolyte for lithium ion batteries. J Membr Sci 2008; 322: 416–422.

12.

Stephan

Nahm

Kulandainathan

, et al. Poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) based composite electrolytes for lithium batteries. Eur Polym J 2006; 42: 1728–1734.

13.

Tripathi

Shukla

Thakur

, et al. Dielectric modulus and conductivity scaling approach to the analysis of ion transport in solid polymer electrolytes. Polym Eng Sci 2020; 60: 297–305.

14.

Ulaganathan

Lei

Flora

, et al. Charge transport, mechanical and storage performances of sepiolite based composite polymer electrolytes. Chemistry Sel 2016; 1: 5821–5827.

15.

Helen

Ulaganathan

Kesavan

, et al. Synthesis of bendable plasticized nanocomposite polymer electrolyte using poly(acrylonitrile)/poly (methyl methacrylate) polymer blends. Z für Physikalische Chem 2014; 228: 673–684.

16.

Bhide

Hariharan

. Composite polymer electrolyte based on (PEO)6:NaPO3 dispersed with BaTiO3. Polym Int 2008; 57: 523–529.

17.

Ulaganathan

Rajendran

. Studies on MWCNT-incorporated composite polymer electrolytes for electrochemical applications. Soft Mater 2010; 8: 358–369.

18.

Jayanthi

Kokila

Shenbagavalli

, et al. Preparation and characterization of novel potassium ion conducting nanocomposite polymer electrolytes based on PEMA. J Elastomers Plastics 2021. DOI: 10.1177/00952443211038661.

19.

Dey

Das

Karan

, et al. Vibrational spectroscopy and ionic conductivity of polyethylene oxide-NaClO4-CuO nanocomposite. Spectrochimica Acta A: Mol Biomol Spectrosc 2011; 83: 384–391.

20.

Jayanthi

Sundaresan

. Influence of nano SrTiO3 and ultrasonic irradiation on the properties of polymer blend electrolytes. Polymer-Plastics Tech Mater 2020; 59: 2050–2067. DOI: 10.1080/25740881.2020.1784220.

21.

Jayanthi

. Studies on ionic liquid incorporated polymer blend electrolytes for energy storage applications. Adv Composites Hybrid Mater 2019; 2: 351–360.

22.

Jayanthi

Sundaresan

. Effect of ultrasonic irradiation and TiO2 on the determination of electrical and dielectric properties of PEO-P(VdF-HFP)-LiClO4-based nanocomposite polymer blend electrolytes. Ionics 2015; 21: 705–717.

23.

Jayanthi

Arulsankar

Sundaresan

. Nano SrTiO3-filled PEO-P(VdF-HFP)-LiClO4 electrolytes with improved electrical and thermal properties. Appl Phys A 2016; 122: 109.

24.

Ulaganathan

Rajendran

. Preparation and characterizations of PVAc/P(VdF-HFP)-based polymer blend electrolytes. Ionics 2010; 16: 515–521.

25.

Jayanthi

Sundaresan

. Impact of nano titania and ultrasonic irradiation on the structural, electrical, morphological and thermal properties of polymer blend electrolytes. Surf Innov 2021: 1–11. DOI: 10.1680/jsuin.21.00027.