Introduction

Owing to the increasing nature of industrial applications that require a reasonable energy storage capacity as well as source, primarily for electrochemical devices, due attention has been given towards the development of such power source [1,2,3,4,5]. Liquid electrolytes (LE) are extensively used for electrochemical devices rather than other forms of electrolytes due to its high ionic conductivity properties [6, 7]. Previous studies with regard to LE revealed other desirable properties, such as good thermal stability low toxicity [8,9,10]. However, it is worth noting that there are also undesirable issues associated with LE that has been reported in the literature, namely, leakage, poor electrochemical stability, and corrosion reactions with electrode [11]. These drawbacks have somewhat render LE less attractive for electrochemical devices. Solid biopolymer electrolytes (SBEs) have been demonstrated to be a viable promising alternative to LE. SBEs are the formation of salt dispersed in a polymer matrix into an ion conducting system. The salt mainly supplies mobile ions while the polymer host acts as a solvent in SBEs. The potential application of SBEs have been recognized due to its low energy density properties, ease of preparation, lightweight, leakage free, and excellent mechanical properties [12,13,14,15].

There are a number of renewable biopolymer-based resources that are suitable as host polymers, such as starch [16], chitosan [17], hydroxyethyl cellulose [18], and agarose [19, 20] amongst others. Alginate is a linear polysaccharide that comes from the family of carbohydrates as shown in Fig. 1 [21], which is a derivation of brown algae, and it is a natural polymer that is water soluble [22, 23]. Chemically, alginate is made up of β-D-mannuronic acid and α-l-guluronic acid monomers [24, 25] and it has gained due attention primarily due to its low cost, biocompatibility, highly hydrophilic, and not toxic [26,27,28]. Therefore, owing to the aforesaid properties, this particular natural polymer has the potential of becoming a promising candidate for renewable-based polymer electrolytes.

Fig. 1
figure 1

Optimized molecular structure of alginate retrieved from the Gaussian software

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As such, this work focuses on the potential of alginate as the polymer host and ammonium nitrate as the ionic dopant. It is worth noting that ammonium salt is believed to be an excellent proton donor. The transportation of ions of the developed system is also investigated to evaluate to what extent does the ionic conductivity enhancement it yields against other systems developed [29, 30]. To the best of the authors’ knowledge, the present investigation is novel. The present system is characterized by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), electrical impedance spectroscopy (EIS), transference number measurement (TNM), and differential scanning calorimetry (DSC) respectively.

Material and methods

Sample preparation of SBE thin film

Approximately, 2 g of alginate (Sigma-Aldrich Co.; MW 12,000–40,000) was dissolved into distilled water. Then, different amounts of NH4NO3 (5–35 wt.%) was added into the alginate solution, and the solution was stirred until it becomes homogeneous. The homogenous solution of alginate–NH4NO3 was cast into a petri dish and was left to dry at room temperature to obtain the alginate–NH4NO3 films. The designation of the samples is shown in Table 1.

Table 1 Designation of the alginate-ammonium nitrate
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Characterization of SBE thin film

Fourier transform infrared spectroscopy

The complexation of the sodium alginate and ammonium nitrate is examined via Perkin Elmer 100 attenuated total reflection (ATR) FTIR spectroscopy with germanium crystal. The sample was placed on germanium crystal, and the infrared light was passed through the sample within the frequency range from 4000 to 700 cm−1 with a resolution of 2 cm−1.

X-ray diffraction

The XRD pattern of alginate–NH4NO3 SBE system was performed by using a Rigaku MiniFlex II diffractometer. The sample was cut into a suitable size and then placed onto a glass slide. The spectra of XRD scanned were fixed at 2θ between 5° and 80° using CuKα as the radiation source. The crystallite size (D) analysis was carried out via the full width half maximum (FWHM) information. The calculation is based on the Debye-Scherrer equation as shown below [31, 32]:

$$ D=\frac{K\lambda}{\mathrm{FWHMcos}\ \theta } $$
(1)

where K = 0.94, λ = 0.154 nm, and θ = peak location.

Electrical impedance spectroscopy

Ionic conductivity of SBE system was characterized by using HIOKI 3532-50 LCR Hi–Tester at an ambient temperature of 343 K with a frequency range from 50 Hz to 1 MHz. The ionic conductivity, σ, of the electrolyte was measured using the following equation:

$$ \sigma =\frac{t}{R_{\mathrm{b}}A} $$
(2)

where t is the thickness of the electrolytes, Rb is the bulk resistance which was obtained from the plot of imaginary impedance (Zi) versus real impedance part (Zr), and A is the electrode-electrolyte contact area (cm2).

FTIR deconvolution

The FTIR deconvolution analysis was carried out via the Origin Lab 8.0 software. The area under the peak was determined, and the free ions (%) were calculated using the equation as follows [33,34,35,36]:

$$ \mathrm{Percentage}\ \mathrm{of}\ \mathrm{free}\ \mathrm{ions}\ \left(\%\right)=\left(\frac{A_{\mathrm{f}}}{A_{\mathrm{f}}+{A}_{\mathrm{c}}}\right)\times 100\% $$
(3)

where Af is the area under the of the free ions region, while Ac is the total area under the peak of the contact ions. The number (η), mobility (μ), and the diffusion coefficient (D) of the mobile ions are determined by using the following equations [33,34,35,36,37]:

$$ \eta =\left(\frac{M{N}_{\mathrm{A}}}{V_{total}}\right)\times \mathrm{free}\ \mathrm{ions}\ \left(\%\right) $$
(4)
$$ \mu =\frac{\sigma }{\eta e} $$
(5)
$$ D=\left(\frac{kT\mu}{e}\right) $$
(6)

In this work, M is the number of moles of the salt based on weight percentage, NA is Avogadro’s number, and Vtotal is the total volume of the SBE system, while e is the electric charge, k is the Boltzmann constant, and T is the absolute temperature in Kelvin.

Transference number measurement

Transference number measurement (TNM) was measured using a direct current (DC) polarization technique [38, 39] to evaluate the quality of the ionic conduction. The DC value was monitored as a function of time by using a cell potential of 1.5 V across the sample sandwiched between two stainless steel electrodes. To calculate the ionic transference, tion value, the following equation is employed [40]:

$$ {t}_{\mathrm{i}\mathrm{on}}=\left({I}_{\mathrm{i}}-{I}_{\mathrm{s}}\right)/{I}_{\mathrm{i}} $$
(7)
$$ {t}_{\mathrm{ele}}=\left({I}_{\mathrm{s}}/{I}_{\mathrm{i}}\right) $$
(8)

where Ii and Is are the total and residual currents, respectively.

Differential scanning calorimetry

The thermal properties of this work were determined through a NETZSCH5 differential scanning calorimetry (DSC). The glass transition temperature (Tg) of the different SBE sample (4 mg) was measured at a heating scan rate of 10 °C/min from 30 to 550 °C.

Results and discussion

FTIR analysis

The FTIR analysis evaluates the complexation between the host polymer and the salt. This analysis is non-trivial to further understand the conduction mechanism of the proposed SBE system. The IR spectrum of pure alginate and ammonium salt is presented in Fig. 2, and their functional groups are tabulated in Table 2.

Fig. 2
figure 2

The IR spectrum of powder of alginate and pure ammonium salt

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Table 2 List of band modes of alginate-ammonium nitrate
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The primary bands that exist with the coordinating site (oxygen) in alginate are the stretching of COO−, –OH, and C–O–C bending. These bands are demonstrated to be significant and are highlighted if any changes of peaks occur in these functional groups. The molecular structure of alginate is quite similar to carboxymethyl cellulose (CMC) as the only difference between them is the presence of the carboxymethyl group on CMC as reported by other researchers [49, 50].

The functional groups of interest for the SBE which represent the complexes of alginate–NH4NO3 are highlighted in Fig. 3. Based on Fig. 3, it shows that the FTIR spectrum of alginate-ammonium nitrate SBEs that are defined at peaks 1415 and 1598 cm−1 corresponds to the present of COO− stretching of carboxylate anion of (C=O) and (C–O−) in alginate, respectively [43, 45, 51]. The absorption by carbon dioxide (CO2) may be observed with a sharp peak between 2200 and 2700 cm−1. It is evident from Fig. 3a that the intensity of the peak at 1598 cm−1 was found to increase with the addition of the NH4NO3. It is also observed that only a slight change in the wavenumber of 7 cm−1 resolution. Meanwhile, the peak at wavenumber 1415 cm−1 is found to shift to a lower wavenumber (1406 cm−1) upon the addition of 25 wt.% NH4NO3 and disappears beyond the value. These apparent changes are expected at this functional group, primarily due to the coordination interaction between (COO−) in the alginate with H+ of [NH4+] substructure in NH4NO3 which reflects the protonation (either by C–O−⋯H+NH3+ or C=O⋯H+NH3+).

Fig. 3
figure 3

a FTIR spectrum between 1500 and 1800 cm−1, b FTIR spectrum between 1200 and 1500 cm−1, c FTIR spectrum between 900 and 1200 cm−1, and d FTIR spectrum between 3000 and 3700 cm−1

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It was observed that the increase of NH4NO3 composition in alginate resulted in a higher concentration of H+. Accordingly, more ions are inhibited towards the alginate via (COO−) to form hydrogen bonding, and this phenomenon is demonstrated through the shifting of peak to the lower wavenumber. This phenomenon has also been reported in previous studies [35, 52] where the authors’ believed that the H+ ion that originated from the ammonium salts acts as a conducting ion which migrates towards the anion group in polymer electrolyte system. The conduction takes place through the Grotthus mechanism when there is an electric field applied, and this is related to the exchange of ions between complexed sites, suggesting that complexation has taken place between the biopolymer and ionic dopant. The disappearance of the peak at ~ 1415 cm−1 could be either due to the higher composition of NH4NO3 that did not associate or the ions that recombine to form neutral ion pairs. A similar observation was made by Mason et al. [53] and Kadir et al. [54] in their respective works. A new peak was observed at 1390 cm−1 in the entire SBE system, and this can be attributed to the existence of NH4+ from NH4NO3. The interaction consequently results in the increase of relative intensity due to the increment of the NH4NO3 composition. These occurrences could be attributed to the coordination of NH4+ ions with the polar group present in the alginate group when NH4NO3 was introduced into the system. Other researchers [55, 56] that utilize ammonium salts as a dopant in polymer electrolyte system also observed similar behavior. The authors opined that the new peak that appears at wavenumber ~ 1400 cm−1 corresponds to the NH4+ ions of the ammonium salts.

Another evidence to further suggest that the complexation has taken place is noticeable at wavenumber 1019 cm−1 (C–O–C of alginate) which was observed to shift to a higher wavenumber (1028 cm−1) when NH4NO3 was added in the present system. The changes of IR peak in this region can be due to the migration of NH4+ towards C–O–C. There are strong contributions of hydrogen bonding and coordination interaction of H+ to the C–O–C between alginate and NH4NO3 as found in other similar systems using ammonium salts [54]. There are two possible charge carrier components in the polymer–salt electrolyte systems either cation or anion [55] and this can be demonstrated from transference number measurement analysis. Based on previous reports [56, 57], it is believed that H+ is the only cation that contributes towards the ionic transport properties, and this further establishes that the entire event occurred at coordinating site (oxygen) of the host biopolymer (alginate).

On the other hand, it can be seen that –OH stretching transpired at wavenumber 3393 cm−1 for the un-doped SBE system. It could be seen that with the addition of NH4NO3 in SBE system, a broad absorption peak of OH stretching at 3393 cm−1 is shifted to a higher wavenumber of 3452 cm−1. A new peak was observed at 3271 cm−1 with the addition of 15 wt.% NH4NO3, and this could be attributed due to the presence of asymmetrical N–H stretching from NH4NO3. In addition, there is an overlapping of peaks observed in the –OH region which leads to the shifting of –OH group in alginate when NH4NO3 was introduced. This event is found to be similar as observed by other researchers who utilized NH4NO3 as an ionic dopant in polymer electrolyte system [47, 49]. Table 3 summarizes the changes in the wavenumber where it is believed that complexation has occurred between alginate and NH4NO3 in SBE system.

Table 3 Summary of complexation between alginate and NH4NO3 for the SBE system
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XRD analysis

The XRD patterns of solid biopolymer electrolyte (SBE)-based alginate with different composition of NH4NO3 are shown in Fig. 4. In the present system, the addition of NH4NO3 is expected to assist the biopolymer host in enhancing the amorphous phase in the SBE system [61]. Based on Fig. 4, the semi-crystalline hump was found at ~ 13°, ~ 21°, and ~ 38° for sample S0, which corresponds to the un-doped sample. Previous research report that the pure alginate powder consists of two main semi-crystalline peaks which can be found at 2θ = 13.7° and 23.0° [62, 63]. It is evident that as the composition of NH4NO3 is increased, the hump became more broaden and shifted to the higher angle indicating that the complexation has occurred between biopolymer host and ionic dopant. This observation revealed that the decrement of the crystalline phase in alginate occurs upon the addition of NH4NO3 which suggests that the amorphous phase has taken place in the SBE system. The amorphous phase contributes towards the increment of protonation of (H+) in alginate and consequently improves the conductivity of the present system.

Fig. 4
figure 4

XRD spectrum for the alginate–NH4NO3-based SBE system

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The analysis based on the crystallite size (D) in the present SBE system was carried out by using Eq. (1) to further investigate the effect of the addition of NH4NO3 in alginate. The full width at half maximum (FWHM) for each crystal peak/amorphous halo was observed and calculated using the PDXL software. The lists of crystallite size (D) for of alginate–NH4NO3 SBE system are tabulated in Table 4. It can be seen that the crystallite size of alginate decreases with the introduction of NH4NO3 and the sample that contains 25 wt.% of NH4NO3 (sample S5) exhibits only a single FWHM value which is also the lowest value of crystallinity in the present system. This finding indicates that only the amorphous phase was present. Previous studies [64,65,66] revealed that samples of polymer electrolytes with a lower crystallite size would exhibit high ionic conductivity, and hence, in the present system, it is expected that sample S5 possesses the highest ionic conductivity in SBE system.

Table 4 Crystallite size of the alginate–ammonium nitrate SBE system
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It can be observed that the crystallinity behavior begins to appear between the ~ 14° and 40° region, in which the alginate was added more than 25 wt.% NH4NO3. The crystal peaks correspond to the appearance of NH4NO3 and alginate semi-crystalline phase. This implies that the alginate cannot solvate the NH4NO3 any longer due to the huge amount of H+ concentration supplied to the SBE system that in turn blocks the ions migration. Consequently, the overcrowding of the ions led to the increase in crystallinity. The appearance of the crystalline peak also indicates that the deprotonation process has occurred as shown in the FTIR analysis. Based on XRD results, it is expected that the transport properties and ionic conductivity in the present sample decreases.

Ionic conductivity analysis

The ionic conductivity of alginate–NH4NO3 SBE system at ambient temperature (303 K) is presented in Fig. 5. The ionic conductivity for the un-doped alginate SBE system was observed to be 2.94 × 10−7 S cm−1, and with the addition of NH4NO3, the ionic conductivity began to increase towards a higher value. The dependence of the ionic conductivity on the NH4NO3 composition provides some insight into the specific interaction between the NH4NO3 and the alginate biopolymer matrix. The increase of the ionic conductivity in the alginate–NH4NO3 SBE system can be attributed to the ion association of proton H+ as demonstrated in the FTIR study apart from the increment in transport properties [67,68,69]. In alginate–NH4NO3 SBE system, the ammonium salt will complex with the coordinating site (oxygen) of the alginate host. Hence, there will be more sites at which ion hopping and exchange can take place leading to an increase in conductivity. Moreover, XRD results also suggest that the increasing amorphous phase in the SBE system leads to an increase in the ionic conductivity.

Fig. 5
figure 5

Ionic conductivity of the alginate–NH4NO3 SBE system at ambient temperature

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The ionic conductivity achieved a maximum value at 5.56 × 10−5 S cm−1 for the sample containing 25 wt.% of NH4NO3 and this range of ionic conductivity value exhibited by the present system (~ 10−5 S/cm) is adequate enough to be applied as a supercapacitor [70] or EDLC [71] and proton battery [72] in electrochemical devices. However, it is worth noting that an increase of beyond 25 wt.% NH4NO3, the ionic conductivity of SBE system starts to decrease, and the decrement in the ionic conductivity can be attributed to the re-association of the H+ that changes into the neutral aggregation in ion cluster [73,74,75] as shown by FTIR result. In addition, the reason for such decrease in ionic conductivity may be due to the excess salt recrystallized out of the alginate as demonstrated by XRD result, which leads to an increase in the energy barrier to the segmental motion in the SBE system [76, 77].

Figure 6 presents the ionic conductivity at a different temperature range from 303 to 343 K for SBE system. Based on Fig. 6, it can be observed that the ionic conductivity increases gradually with temperature for all samples and the regression value, R2 is observed to be close to unity (R2 ~ 1) suggesting that all composition for alginate–NH4NO3 SBE system s are thermally activated and obey the Arrhenius behavior [78, 79]. This observation suggests that the ionic conductivity of the polymer electrolytes increases with temperature, and more often than not, it is commonly due to the increment in free volume in the present system allowing for the motion of the ions through the biopolymer backbone. Therefore, free volume around the biopolymer chain causes augmentation in mobility of ions and hence enhances the ionic conductivity with temperature. A similar result also has been reported with different types of polymer electrolyte system [52, 80, 81]. The Arrhenius relation can be expressed by

$$ \sigma ={\sigma}_0\ \exp \left(-\frac{E_{\mathrm{a}}}{kT}\right) $$
(9)

where Ea is the activation energy, σ is the conductivity of SBE system, σ0 is the pre-exponential factor, k is the Boltzmann constant, and T is the temperature.

Fig. 6
figure 6

Conductivity at different temperature of the alginate–NH4NO3 SBE system

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The activation energy, Ea, values for alginate–NH4NO3 SBE system are plotted in Fig. 7. It can be observed that the value of Ea generally decreases as the ionic conductivity increases and evidently it is found to be the smallest Ea is demonstrated by the sample with the highest conductivity, i.e., at 25 wt.% of NH4NO3. This observation suggests that the ions which correspond to H+ only requires lower energy to migrate to the coordinating sites (oxygen) in alginate and, in turn, enhances the ionic mobility. This is in agreement with the fact that the amount of ions in the SBE system increases with the increase in NH4NO3 composition, the energy barrier for the hopping decreases and leads to a decrease in the activation energy of the present system [78]. In addition, the low activation energy is due to the richness of amorphous phase in SBE system that facilitates a faster rate of H+ ion motion in the biopolymer network [69, 75, 82, 83].

Fig. 7
figure 7

Activation energy for the alginate–NH4NO3 SBE system

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FTIR deconvolution

Figure 8 indicates the FTIR deconvolution of various samples of the SBE system. The region between 1500 and 1200 cm−1 is selected as it is believed that complexation has occurred [84, 85] as observed in FTIR analysis. Based on Fig. 8, the free ions represent the free mobile ions (∼ 1350 cm−1 to ~ 1400 cm−1), and the contact ions pairs (∼ 1420 cm−1 and ∼ 1350 cm−1) represent the contact ions and ion aggregates in the biopolymer system [35]. The free and contact ions were computed from the ratio of the area of free or contact ions to the total area of deconvolution peaks, respectively, and are tabulated in Table 5. The maximum ionic conductivity was observed is due to the maximum free ion formation as mentioned in the ionic conductivity analysis. This result supports the ionic conductivity observation in this SBE system.

Fig. 8
figure 8

FTIR deconvolution for various sample of the SBE system

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Table 5 Percentage area of free and contact ions of the alginate–NH4NO3 SBE system
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It can be seen that the percentage of free ions increases as the composition of NH4NO3 is increased until sample S5 has similar conductivity pattern. The increase of free ions indicates that more H+ is dissociated from NH4+ which would lead to an increase in ionic conductivity.

Based on Table 5, the number of ions, η, mobility of ions, μ, and diffusion coefficient, D, were calculated using Eqs. (4), (5), and (6) and are presented in Fig. 9. From Fig. 9, it is apparent that the numbers of ions (ƞ) increases gradually with the increase of NH4NO3, meanwhile the mobility of ions (μ) and the diffusion coefficient (D) are found to be aligned with the ionic conductivity pattern. It can be noted here that the increasing ƞ values increase the ionic conductivity of the present system and this can be shown from the free ions values, which gradually increases with the addition of NH4NO3 to the SBE system. As the sample becomes more amorphous, H+ migrates and interacts with COO− of alginate more efficiently, enhancing the ionic conductivity along with transport properties until the optimum value is reached.

Fig. 9
figure 9

Transport parameters of the alginate–NH4NO3 SBE system

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However, beyond 25 wt.% NH4NO3, it was shown that the ƞ value drastically increases to a higher value and meanwhile the μ and D are found to drop. This observation reveals that the present system is over-filled with huge concentration of ions (H+) and in order to hop towards COO−, it requires a huge amount of activation energy, which reflects towards the mobility and diffusion rate to drop [86, 87]. Besides, the appearance of the crystallinity peak for samples S6 and S7 as shown in the XRD analysis suggests that the pathway for ions hopping are limited. This is due to the blocking pathway for the transition of ions created by crystalline phase in the SBE system, consequently decreasing their mobility, diffusion, and ionic conductivity. This behavior is found to be in agreement with other research works on polymer electrolyte system [55, 66, 88].

Transference number measurement study

The transference number measurement is carried out to determine the conduction species (either cations or anions) in polymer electrolyte system. The plots of normal polarized current versus time of the highest conducting sample in SBE system are illustrated in Fig. 10. The plots indicate that the initial total current, (Ii) decreased along the time and became plateau in the fully depleted state. The reason for the decrease of the ionic current is due to the reduction of the ionic conduction of the sample of alginate–NH4NO3. At steady state, the polarization occurred with current flows along the cell due to the presence of electrons across the electrolyte and the interfaces. One of the reasons for the ionic current to fall rapidly in an ion-blocking electrode is because the electrolyte is a cation. The ionic transference number and electron transference number of the highest in ionic conductivity were found to be 0.97 and 0.03, respectively. Thus, it can be inferred that the sample is dominantly due to the ions (H+) from NH4NO3 complexed with alginate SBEs which are expected to be proton as the value of tion ∼ 1 and this observation is also found to be in agreement with other similar works [89,90,91].

Fig. 10
figure 10

The normal polarized current versus time for sample S5

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Differential scanning calorimetry analysis

Transport properties are affected by the presence of H+ in the amorphous phase, which is characterized by the glass transition temperature (Tg) [92]. Figure 11 shows a typical plot of the DSC curves for the un-doped alginate and the highest conducting sample (25 wt.% NH4NO3) which has been recorded on the heating run temperature ranging from 30 to 300 °C. It can be observed that the glass transition temperature, Tg, of pure alginate is 66.44 °C and this value is observed to be similar to the literature [93, 94]. Meanwhile, the Tg of alginate doped with 25 wt.% of NH4NO3 is found to be 64.09 °C, and the decrease in the Tg value may be attributed by the presence of NH4NO3 that increases the dissociation of H+ from NH4NO3 for migration. With the increment of the amorphous phase in SBE system, the inhabitation of ionic motion to occur is also increased due to the increase in ionic coordination at the biopolymer host, that in turn, decreases the Tg value and raises the ionic conductivity of present system to a higher value [95,96,97]. Other researchers [98] have also reported the decrease in transition temperature as similarly reported in this work. In addition, the melting peak, Tm appears at 204.90 °C (S0) and 205.59 °C (S5), respectively. The value of Tm is observed to not to shift significantly; this is possibly be due to the physical entanglement of alginate polymer chains which limits the segmental motion of alginate [95].

Fig. 11
figure 11

DSC curves of pure alginate and 25 wt.% of NH4NO3

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Conclusion

In the present work, solid biopolymer electrolyte (SBE) system based on alginate doped with NH4NO3 was successfully prepared via solution-casting technique. The prepared samples were characterized using several techniques, namely, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and electrical impedance spectroscopy (EIS), transference number measurement (TNM) and differential scanning calorimetry (DSC). The complexation between alginate and NH4NO3 was established based on the changes of the peak which is observed from the coordinating site in alginate (COO−, C–O–C, and –OH). The H+ which originate from an N-H4+ group of NH4NO3 is believed to act as conducting ions in the present system and lead to the increment in the amorphous phase as shown from the XRD results. The ionic conductivity of SBE system was found to increase from 2.94 × 10−7 and attained the highest ionic conductivity of 5.56 × 10−5 S cm−1 at ambient temperature for the sample containing with 25 wt.% NH4NO3. The temperature dependence observed in the present system indicates that the SBE system follows the Arrhenius behavior and is thermally activated. The calculated activation energy was found to be inversely proportional with ionic conductivity of SBE system, and sample S5 only requires a small amount of energy for ion migration. Based on the deconvolution method, the transport properties were calculated and revealed that the ionic conductivity of SBE system is governed by the mobility of ions and diffusion coefficient rate. Moreover, from the TNM analysis, it could be observed that the sample with the highest conductivity has a transference number tion of 0.97 suggesting that the conductivity is cation driven. Furthermore, the DSC analysis indicates that the decrease in the glass transition temperature (Tg) is correlated with the increase of the NH4NO3 composition in the present system.