Startseite Mixed gel electrolytes: Synthesis, characterization, and gas release on PbSb electrode
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Mixed gel electrolytes: Synthesis, characterization, and gas release on PbSb electrode

  • Phan Thi Binh EMAIL logo , Nguyen Thi Van Anh , Mai Thi Thanh Thuy , Mai Thi Xuan , Nguyen The Duyen , Vi Thi Chuyen und Bui Minh Quy
Veröffentlicht/Copyright: 31. Mai 2021
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Green Processing and Synthesis
Aus der Zeitschrift Green Processing and Synthesis Band 10 Heft 1

Abstract

Mixed gel electrolytes were fabricated chemically at a temperature range of 2–5°C using some additives comparing with traditional electrolytes (1.26 g/cm3 H2SO4). The polyacrylamide (PAM) content is kept constant (0.2 wt%), while the propylene glycol (PPG) and nano fumed silica (NFS) contents varied. The material characteristics of samples were assessed by physical appearance observation, electrochemical measurements, and physicochemical methods. The results showed that a hard gel without separation of solutions was found in the case using a PAM/PPG/NFS ternary additive (0.2/0.1/0.6 wt%). The morphological structure (<50 nm) of mixed gel electrolytes was in the range of nanometer. The gas release on the PbSb electrode was strongly inhibited (92.2–93.7% for O2 and ∼55% for H2 at the 120th cycle), which will both contributes to reducing the pressure as well as limiting water loss in the sealed lead acid battery, compared with that in the sulfuric acid medium.

Keywords: mixed gel electrolyte; additives; ionic conductivity; diffusion coefficient; gas release

1 Introduction

Currently, mixed gel electrolytes are of concern for scientists in the field of sealed lead acid batteries [1,2,3,4] because there is no need for maintenance, and acid vapors that can damage the surroundings are also controlled. To improve them, various additives as gelling agents were used. For example, vanillin is referred to as a gelling agent that enhances battery deep discharge but reduces capacity after a storage period of only 3 months [4]. Some polyols such as propanetriol, butanetriol, pentitol, and pentaerythritol can facilitate the gelation process due to the ability to repel water molecules from the hydrate layer surrounding SiO2 [5]. However, their electrochemical properties are also affected by the length of the carbon branch and the number of OH groups. PAM is an additive that both reduces the gelling time and increases the hardness of gelled electrolytes, which can increase the discharge capacity of batteries [4,6,7]. PPG is a well-expanding polymer with natural hydrophobic properties, which are used for the synthesis of organo-modified SBA-15 [8]. However, it is not yet used as an additive in the manufacture of gel electrolytes for the battery. According to the previous research, mixed gel electrolytes could retain more sulfuric acid compared with that using a single gelling agent [9]. The charge transfer resistance at the open circuit potential (OCP) can also be reduced because of their three-dimensional structures, leading to an improved initial capacity of the gel battery. Several oxides such as TiO2, Al2O3, and B2O3 have been studied for fuming silica (up to 6%)-based gel electrolyte system [3]. However, its viscosity increased due to the presence of B2O3, and the three-dimensional space structure decreased because Al2O3 was not well connected with the isolated silanol groups, except for TiO2 because of its ability to form a three-dimensional space like fuming silica.

This article presents some results about mixed gel electrolytes containing PAM, PPG, and NFS (in various weight percent) compared with traditional electrolytes. The aim of the study is to synthesize mixed gel electrolytes, to evaluate the properties of materials, and to investigate the gas release at PbSb electrodes in different electrolytes. The relationship between the material properties and the diffusion capacity of the HSO 4 − ion in mixed gel electrolytes will be elucidated.

2 Materials and methods

Chemicals used in this study were provided by Sigma Aldrich (NFS 7 nm; PAM), Merck (PPG, H2SO4), and China (alcohol; Na2SiO3·xH2O (1.54 g/cm3)).

2.1 Sample manufacturing

The temperature was kept in the range of 2–5°C for material synthesis. H2SO4 solution (1.37 g/cm3) and Na2SiO3·xH2O (1.54 g/cm3) were used in the volume ratio of 3.2/1.0 for sample preparation. A fresh 5% NFS suspension was used as one of the additives whose content was (in weight percentage) compared with the mass of sulfuric acid. The content of PAM was constant (0.2 wt%), while the content ranges of PPG and NFS were 0.0–0.4 wt% and 0.2–0.8 wt%, respectively. After synthesis, the samples were washed with alcohol to remove water from the gel. They were then dried at 40°C for a while to provide for measuring infrared spectroscopy measurement, X-ray diffraction, SEM imaging, and thermal analysis.

2.2 Research methods

First, the physical appearance of samples was observed visually after fabrication. Their ionic conductivity was then measured on electrochemical equipment (IM6, Zahner-Elektrik, Germany) using the EIS method. Two stainless steel electrodes were used for the cell in EIS measurements at OCP (frequency: 8 MHz–1 kHz; amplitude: 5 mV). The resistance of electrolytes is the value of the intersection between the Nyquist line and the horizontal axis following Thales Software [10]. The ionic conductivity χ (in S/cm) can be determined by Eq. 1, in which l is the length of electrolyte block (in cm), A is the cross section of this block (in cm2), and R Ω is the electrolyte resistance (in Ω).

(1) χ = l A R Ω .

The HSO 4 − ions play an important role in the electrode reactions of lead acid batteries, so their diffusion coefficient should be considered in this study. It can be detected by the cyclic voltammetry (CV) method (scanning speed: 30–100 mV/s; potential range from −1.5 to −0.5 V; PbSb material as a working electrode; platin sheet as a counter electrode; and Hg/Hg2SO4/sat.K2SO4 as a reference electrode). The plot is constructed from the Randles–Sevcik equation at 25°C to determine the diffusion coefficient D o [11] following Eq. 2:

(2) i p = 2.69 × 10 5 n 3 / 2 A D o 1 / 2 C o v 1 / 2

where i p is the oxidation peak (in A/cm2), n is the exchange electronic number, A is the electrode surface area (in cm2), D o is the diffusion coefficient (in cm2/s), C o is the initial concentration of the oxidant (in mol/cm3), and v is the scan rate (in V/s).

The stability of the mixed gel electrolyte and the gas release were also observed by CV measurements with the same three-electrode cell. One hundred twenty CV cycles were carried out at a scan rate of 100 mV/s (potential range: from −1.5 to 2.1 V). The amount of electricity devoted to the oxygen release is calculated by the peak integral in the oxygen draining zone thanks to Thales Software [10].

The infrared spectrum was measured in the wavelength range from 4,000 to 400 cm−1 on the Spectrum Two FTIR Spectrometers by Perkin Elmer (USA). The crystal structures of samples were analyzed on X-ray diffractometer D5000-Siemens (Germany) in the interval of 5–115°. The morphology of the samples was assessed by SEM images taken on the FE-SEM Hitachi S-4800 (Japan) with 5 kV voltage acceleration. The thermal stability of the materials was examined using a Setaram (France) simultaneous differential thermal analyzer (DTA/DSC/TGA) apparatus (Labsys Evo S60/58988) under a 120 mL/min flow of argon atmosphere at a heating rate of 10°C/min from room temperature to 800°C.

3 Results and discussion

3.1 Physical appearance of mixed gel electrolytes

The results in Table 1 show the significant influence of additives on the physical appearance of fabricated samples. The state of the sample was found to exist in its normal form without solution separation at the PAM content of 0.2 wt%. However, when adding PPG in combination with PAM, this state is only achieved if the PPG content does not exceed 1% by weight. The reason may be due to the hydrophobic nature of PPG [8], which can cause water to be easily separated from the gel if the PPG content exceeds 1 wt%.

Table 1

Physical appearance of mixed gel electrolyte containing different additives

Sample no Content of additives in mixed gel electrolyte (wt%) Physical appearance of mixed gel electrolyte
PAM PPG NFS
1 0.2 0.0 Normal gel
2 0.2 0.1 Normal gel
3 0.2 0.2 Solution splitting
4 0.2 0.3 Solution splitting
5 0.2 0.4 Solution splitting
6 0.2 0.2 Poor gel
7 0.2 0.4 Poor gel
8 0.2 0.6 Soft gel
9 0.2 0.8 Poor gel
10 0.2 0.1 0.2 Normal gel
11 0.2 0.1 0.4 Normal gel
12 0.2 0.1 0.6 Hard gel
13 0.2 0.1 0.8 Normal gel

Samples containing 0.2 wt% PAM and NFS (0.2–0.8 wt%) showed that the majority of the resulting products were generally less durable. One of them was found to be stable in a soft gel state for NFS at 0.6% by weight. When PPG (0.1 wt%) was added to them, the physical state of samples improved significantly. In which the state of the sample using 0.6 wt% NFS changed from a soft gel to a hard gel. This means that if the NFS is used inadequate (<0.6% by weight) or excess (>0.6% by weight) in the presence of PPG (0.1% by weight), then the hydrogen bonds in water in the Si–O–Si network will become loose, resulting in only normal gel formation and less stiffness.

3.2 Ionic conductivity

Figure 1(a–c) shows the Nyquist diagrams measured in different mixed gel electrolytes. An electrical equivalent circuit (EEC) was found (d) with five elements by simulation following the Thales Software [10]. These include L, R Ω, C d, R ct, and W, which refer to the inductive element (relaxation impedance), the resistance of gel electrolyte, a double-layer capacitance, the resistance of charge transfer, and a Warburg diffusion element, respectively. The fitting error less than 10% shows that the EEC is quite consistent with the experimental results.

Figure 1 Nyquist diagrams in different mixed gel electrolytes using: (a) various content of PPG adding PAM (constant content), (b) various content of NFS adding PAM (constant content), (c) various content of NFS adding PAM & PPG (constant content); and (d) electrical equivalent circuit (EEC).
Figure 1

Nyquist diagrams in different mixed gel electrolytes using: (a) various content of PPG adding PAM (constant content), (b) various content of NFS adding PAM (constant content), (c) various content of NFS adding PAM & PPG (constant content); and (d) electrical equivalent circuit (EEC).

The ionic conductivity (see Table 2) is calculated using Eq. 1, in which the resistance R Ω is the intersection value between the Nyquist line and the horizontal axis with an error of less than 5%. Its value ranges from 0.40 to 0.56 S/cm, in which the lowest one (0.40 S/cm) belongs to the sample using ternary additive (PPG, PAM, and NFS with 0.1, 0.2, and 0.8 wt%, respectively), and the highest one belongs to the sample using binary additive (PAM/PPG (0.2/0.3 wt%)).

Table 2

Determination of ionic conductivity of mixed gel electrolytes

Content of additives in mixed gel electrolytes (wt%) R Ω (Ω) Ionic conductivity (S/cm) Main physical state
PAM PPG NFS Value Error (%)
0.2 0.0 11.11 3.58 0.47 Normal gel
0.2 0.1 9.93 3.59 0.52 Normal gel
0.2 0.2 9.43 3.67 0.55 Solution splitting
0.2 0.3 9.21 3.39 0.56 Solution splitting
0.2 0.4 10.44 3.76 0.50 Solution splitting
0.2 0.2 10.66 0.71 0.49 Poor gel
0.2 0.4 9.98 0.60 0.52 Poor gel
0.2 0.6 9.60 2.08 0.54 Soft gel
0.2 0.8 9.83 1.49 0.53 Poor gel
0.2 0.1 0.2 11.58 3.61 0.45 Normal gel
0.2 0.1 0.4 12.78 4.75 0.41 Normal gel
0.2 0.1 0.6 12.36 4.38 0.42 Hard gel
0.2 0.1 0.8 12.98 4.21 0.40 Normal gel

After studying the physical appearance and the ionic conductivity, four representative samples 1 and 2 (normal gel for single PAM and binary PAM/PPG additives, respectively), 8 (soft gel for binary PAM/NFS additive), and 12 (hard gel for PAM/NFS/PPG ternary additive)) were selected for further study. The reason for this choice is that the samples should be gel like without solution separation. This is related to the ionic conductivity and diffusion process of HSO 4 − inside of the gel. Furthermore, it is very necessary because oxygen needs to be transported through the pores in the mixed gel electrolytes from the positive plate to the negative plate to recombine it into water (see reactions 3–6; Eq. 3–6) during a sealed lead acid battery charged [5,12].

(3) O 2 + 2 Pb ↔ 2 PbO .

(4) 2 PbO + 2 H 2 SO 4 ↔ 2 PbSO 4 + 2 H 2 O .

(5) 2 PbSO 4 + 4 H + + 4 e − ↔ 2 Pb + 2 H 2 SO 4 .

The total reaction is as follows:

(6) O 2 + 4 H + + 4 e − ↔ 2 H 2 O .

3.3 Diffusion coefficient of HSO 4 − ions

From observing the physical state of the electrolyte (see Table 1), four representative samples were selected to take CV curves for studying the diffusion of HSO 4 − ions in mixed gel electrolytes. Observing them in Figure 2 shows that oxidation peak appears with an increasing height as the scanning rate changes, but the position of the peak remains virtually unchanged (approximately −0.96 V). This peak shows that an oxidation occurs on the research electrode according to the following reaction:

(7) Pb + HSO 4 − ↔ PbSO 4 + H + + 2 e −

Figure 2 Voltammograms of the PbSb electrode at different scan rate in various mixed gel electrolytes using (a) 0.2 wt% PAM, (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) PAM and NFS (0.2 and 0.6 wt%, respectively), and (d) PAM, PPG, and NFS (0.2, 0.1, and 0.6 wt%, respectively).
Figure 2

Voltammograms of the PbSb electrode at different scan rate in various mixed gel electrolytes using (a) 0.2 wt% PAM, (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) PAM and NFS (0.2 and 0.6 wt%, respectively), and (d) PAM, PPG, and NFS (0.2, 0.1, and 0.6 wt%, respectively).

Eq. 7 shows that the diffusion coefficient in Eq. 2 is considered for HSO 4 − ions. The results from Figure 3 and Table 3 also show that the height of the peak well linearly depends on the square root of the potential scanning speed because of R 2 in the range of 0.96–0.99. This reflects the electrochemical process that happens to be reversible. The diffusion coefficient D o can be calculated from the slope K (= 2.69 × 105 n 3/2 AD o 1/2 C o). In which n, A, and C o are constants with a constant value, except D o. The bigger the K is, the bigger D o is. So instead of comparing the value of D o, we can use the K value to compare the diffusion capacity of HSO 4 − ions in different electrolytes. The results showed that the lowest K value (0.1217 mol/s1/2) belongs to the sample containing the single PAM (0.2 wt%) and the highest one (0.2625 mol/s1/2) indicates the combination of ternary additive (PAM, NFS, and PPG with 0.2, 0.8, and 0.1 wt%, respectively). The results also showed that the diffusion capacity of HSO 4 − ions in the mixed gel electrolyte was improved better by adding NFS whether PPG is present. This is probably due to the formation of the three-dimensional structure thanks to NFS.

Figure 3 The linear plots of i p vs v 1/2.
Figure 3

The linear plots of i p vs v 1/2.

Table 3

The parameters determined from the plots in Figure 3

Additives (wt%) in mixed gel electrolytes Linear equations R 2 K (mol/s1/2)
PAM (0.2) y = 0.1217x − 0.0025 0.9701 0.1217
PPG and PAM (0.1 and 0.2, respectively) y = 0.1858x − 0.0209 0.9906 0.1858
PAM and NFS (0.2 and 0.6, respectively) y = 0.2463x − 0.0196 0.9776 0.2463
PPG, PAM, and NFS (0.1, 0.2, and 0.6, respectively) y = 0.2625x − 0.0377 0.9614 0.2625

3.4 FTIR studies

FTIR spectra shown in Figure 4 and data presented in Table 4 indicate that the peak at near 3,500 cm−1 belongs to the Si–OH and O–H groups linked to molecular water hydrogen as well as the N–H group due to the presence of PAM. The peak appears in interval 1,500–1,700 cm−1 explains the stretching vibration of the SiO2 network or the C═O and C–N resonances of PAM. The peak around 1,055 cm−1 is assigned to the asymmetrical stretching oscillation of the SiO2 network. The peak in interval 900–850 cm−1 describes the symmetrical stretching oscillation of Si–O–Si bonds corresponding to a ring structure. The peaks are located at under 600 cm−1 thanks to the bond bending vibration of Si–O–Si. The obtained data are agreed with the previous studies [13,14].

Figure 4 FTIR spectra of gelled electrolytes using (a) 0.2 wt% PAM, (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) PAM and NFS (0.2 and 0.6 wt%, respectively), (d) PAM, NFS, and PPG (0.2, 0.6, and 0.1 wt%, respectively).
Figure 4

FTIR spectra of gelled electrolytes using (a) 0.2 wt% PAM, (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) PAM and NFS (0.2 and 0.6 wt%, respectively), (d) PAM, NFS, and PPG (0.2, 0.6, and 0.1 wt%, respectively).

Table 4

Data of FTIR analysis from Figure 4 for mixed gel electrolytes

Wavenumber ν (cm−1) Binding
(a) (b) (c) (d)
3,442 3,444 3,435 3,428 Si–O–H group, O–H group of PPG or residual water, N–H stretching of PAM
1,634 1,638 1,639 1,637 C═O and C–N resonance of PAM; combination of vibration of the SiO2 network
1,055 1,055 1,055 1,058 O–Si–O (asymmetrical stretching oscillation of SiO2 network)
881 883 882 882 Si–O–Si (symmetrical stretching oscillation to ring structure)
591, 459 584, 456 592, 459 592, 457 Si–O–Si (bond bending vibration)

The results showed that the presence of PPG beside PAM (b) almost did not change the position as well as the intensity of adsorbed peaks compared without PPG (a). The intensity of the adsorption peak decreased by the presence of NFS next to PAM (c); however, the peak position did not seem to change. Especially in the presence of all of them (d), including PAM, PPG, and NFS, the adsorption peak intensity continued to decrease slightly. In which the peak representing the OH group (3,428 cm−1) was shifted to a lower wavenumber compared with that in the case of the separated PAM (a, 3,442 cm−1). Thus, a slight change in this peak is related to the composition used for the preparation of mixed gel electrolytes. However, in addition to this peak, there is a peak appearing at wavenumber above 1,600 cm−1 (vibration of SiO2 network) related to the ionic conductivity due to proton transfer in their three-dimensional network. This can be explained that the silica particles are exposed during gelling and bonding into a three-dimensional lattice in which the H+ ion can jump from an H3O+ ion (formed during dissociation of H2SO4 in water) to a neighboring H2O molecule as shown in Eq. 8 [15].

The presence of PPG together with NFS and PAM (d) has significantly reduced the peak intensity, reflecting less hydroxyl groups resulting in a decrease in ionic conductivity than the sample containing both NFS and PAM (c). It means that a small portion of NFS in this case would have been involved in the mechanical reinforcement process if it was used in conjunction with PPG.

3.5 X-ray diffraction

All the X-ray spectra in Figure 5 show a wide peak in the interval from 15° to 45° (see peak 1) corresponding to the presence of SiO2 with the same amorphous structure similar to the previous studies [16,17]. An unclear peak appears at the near position of 11° (see peak 2) explains a contribution of PAM. However, this peak almost disappeared when adding PPG and PAM without the presence of NFS (b). The aforementioned results also show that the presence of additives did not affect the amorphous structure of silica.

Figure 5 X-ray spectra of gelled electrolytes using (a) 0.2 wt% PAM, (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) PAM and NFS (0.2 and 0.6 wt%, respectively), (d) PAM, NFS, and PPG (0.2, 0.6, and 0.1 wt%, respectively).
Figure 5

X-ray spectra of gelled electrolytes using (a) 0.2 wt% PAM, (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) PAM and NFS (0.2 and 0.6 wt%, respectively), (d) PAM, NFS, and PPG (0.2, 0.6, and 0.1 wt%, respectively).

3.6 SEM image analysis

Four samples, including numbers 1, 2, 8, and 12 representing different physical states (see Table 1), were selected for SEM imaging and comparing their morphological structure with each other. The results show that the presence of NFS in mixed gel electrolytes contributes to bigger material particle size than without NFS (see Figure 6). It can be explained by an agglomeration of the crystals thanks to the three-dimension structure formed by the presence of NFS. However, observing the SEM images found that all the samples contained crystalline particles in the nano-region (<50 nm).

Figure 6 SEM images of mixed gel electrolytes containing different additives.
Figure 6

SEM images of mixed gel electrolytes containing different additives.

3.7 Thermal analysis

The graphs shown in Figure 7 show three distinct weight loss intervals. The first stage below 100°C reflects desorption of physico-adsorbed water and evaporation of water from sulfuric acid inside the gel. The second stage was recorded at a temperature below 350°C, indicating a dehydroxylation process of silanol (Si–OH) groups [18] to form siloxane (Si–O–Si) bonding of polysiloxane. At higher temperatures, the material is further degraded by the reduced polysiloxane to SiO2, and it seems to stop at about 500°C. The data presented in Table 5 show the exothermic temperatures and the weight loss percent at 200°C, 350°C, and 800°C. From about 100–200°C, a first exothermic appearance is likely due to the formation of new cross-links in the three-dimensional network when the silanol bonds are broken [19]. In the period of less than 350°C, there was a second heat emission, indicating the decomposition of functional groups of organic additives [20]. The percentage reduction in weight of the gel sample using ternary additive (PAM/PPG/NFS) was the least, whereas the rest of the samples lost not only more weight but also the same degree of reduction. According to the previous study [9], the more the weight of material loses, the more the gel become durable and porous. This explained that the gel sample using all three additives formed with a three-dimensional structure less porous than using the single PAM and binary additives (PAM/PPG or PAM/NFS). This is consistent with the results of the SEM image analysis and conductivity measurement in the previous sections.

Figure 7 TGA curves of mixed gel electrolyte using different additives.
Figure 7

TGA curves of mixed gel electrolyte using different additives.

Table 5

Some parameters in thermal analysis of mixed gel electrolytes from Figure 7

Parameter (a) (b) (c) (d)
T Exotherm (°C) 108.41 111.75 116.67 124.16
299.81 282.80 304.85
m loss at 200°C (%) 45.32 43.02 41.21 37.37
m loss at 350°C (%) 57.36 56.38 56.46 47.25
m loss at 800°C (%) 69.38 66.90 68.36 51.32

3.8 Gas release on PbSb electrode

The main idea in studying CV spectra in this section is to consider the escape of gas, including hydrogen and oxygen, which occurs at two potential ranges from −1.2 to −1.5 V and from 1.6 to 2.1 V, respectively. First, we see that this gas release takes place strongly in sulfuric acid solution (see Figure 8e), especially the peak of oxygen release reaching 200 mA/cm2 at the 120th cycle. In addition, we can see that the more the scanning, the higher the rate of oxygen release.

Figure 8 CV curves of the PbSb electrode at 100 mV/s in different mixed gel electrolytes using (a) PAM (0.2 wt%), (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) 0.2 wt% PAM adding 0.6 wt% NFS, (d) PAM, PPG, and NFS (0.2, 0.1, and 0.6 wt%, respectively) compared with that in (e) 1.26 g/cm3 H2SO4 solution.
Figure 8

CV curves of the PbSb electrode at 100 mV/s in different mixed gel electrolytes using (a) PAM (0.2 wt%), (b) PAM and PPG (0.2 and 0.1 wt%, respectively), (c) 0.2 wt% PAM adding 0.6 wt% NFS, (d) PAM, PPG, and NFS (0.2, 0.1, and 0.6 wt%, respectively) compared with that in (e) 1.26 g/cm3 H2SO4 solution.

In contrast, in mixed gel electrolyte (see Figure 8a–d), the release of gas is much lower (for hydrogen <40 mA/cm2 and oxygen <15 mA/cm2) at the 120th cycle comparing with those in H2SO4 solution (90 and 200 mA/cm2, respectively, Figure 8e). It indicates that more than 90% of oxygen and 55% of hydrogen are inhibited thanks to mixed gel electrolytes. The amount of electricity (see Table 6) required to release oxygen in mixed gel electrolytes is generally much lower than in acidic solutions. At the 120th cycle, it requires only 354 μC for oxygen release in mixed gel electrolytes containing PAM and NFS (0.2% and 0.6% by weight, respectively), much lower compared to that in the H2SO4 solution (5,612 μC). It clearly explains that 93.7% oxygen was inhibited. This is very beneficial when using mixed gel electrolytes in the manufacturing of sealed lead acid batteries.

Table 6

Amount of electricity (in μC) for oxygen release in different electrolytes for various CV numbers determined from Figure 8

Number of CV Mixed gel electrolyte Acid sulfuric solution (E)
(A) (B) (C) (D)
1 795.3 338.4 686.2 809.6 2503.0
30 233.0 267.6 280.4 335.7 1135.0
60 237.8 280.0 310.5 357.3 1924.0
90 301.5 322.2 332.3 392.7 3843.0
120 366.9 366.0 354.0 438.4 5612.0

In addition, we can see that the height of peak for oxygen release sharply decreases in mixed gel electrolytes from about 40 mA/cm2 to less than 15 mA/cm2 after the first cycle, and it is almost stable in subsequent cycles. Reducing the rate of gas release, especially oxygen (see Eq. 9), will reduce water loss, so the corrosion of electronic devices around the battery will also decrease as the acid vapors are controlled.

(9) 2 H 2 O → O 2 + 4 H + + 4 e −

This suggests that the mixed gel electrolytes are beneficial in the manufacturing of sealed lead acid batteries because the pressure in the battery is reduced and requires less maintenance due to limiting water loss.

4 Conclusion

The mixed gel electrolytes have been synthesized using a number of additives (PAM, NFS, and PPG). They were characterized by observing their physical shape and electrochemical measurements (EIS and CV) as well as some physicochemical methods (FTIR, X-ray, SEM, and TGA). The outstanding results of this study are as follows: (i) using the ternary additives (PAM/PPG/NFS) provided a mixed hard gel electrolyte with the three-dimensional network structure in the range of nano size, which improved the diffusion of HSO 4 − ion inside the gel; (ii) the mixed gel electrolyte contributes to the reducing gas release (92.2–93.7% O2 and ∼55% H2 at 120th CV) on the PbSb electrode, which is beneficial for making the sealed lead acid battery.

Acknowledgments

This work was financially supported by the National Foundation for Science and Technology Development of Vietnam (grant no.: 104.99-2017.345).

  1. Funding information: This work was financially supported by the National Foundation for Science and Technology Development of Vietnam (grant no.: 104.99-2017.345)

  2. Author contributions: Phan Thi Binh: writing – original draft, writing – review and editing, methodology, formal analysis, and project administration; Nguyen Thi Van Anh: writing – original draft, formal analysis, visualization, and resources; Mai Thi Thanh Thuy: formal analysis and resources; Mai Thi Xuan: resources; Nguyen The Duyen: resources; Vi Thi Chuyen: resources; Bui Minh Quy: resources.

  3. Conflict of interest: The authors state no conflict of interest.

  4. Data availability statement: All data generated or analyzed during this study are included in this published article.

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Received: 2021-02-08
Revised: 2021-04-19
Accepted: 2021-05-04
Published Online: 2021-05-31

© 2021 Phan Thi Binh et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Artikel in diesem Heft

  1. Research Articles
  2. MW irradiation and ionic liquids as green tools in hydrolyses and alcoholyses
  3. Effect of CaO on catalytic combustion of semi-coke
  4. Studies of Penicillium species associated with blue mold disease of grapes and management through plant essential oils as non-hazardous botanical fungicides
  5. Development of leftover rice/gelatin interpenetrating polymer network films for food packaging
  6. Potent antibacterial action of phycosynthesized selenium nanoparticles using Spirulina platensis extract
  7. Green synthesized silver and copper nanoparticles induced changes in biomass parameters, secondary metabolites production, and antioxidant activity in callus cultures of Artemisia absinthium L.
  8. Gold nanoparticles from Celastrus hindsii and HAuCl4: Green synthesis, characteristics, and their cytotoxic effects on HeLa cells
  9. Green synthesis of silver nanoparticles using Tropaeolum majus: Phytochemical screening and antibacterial studies
  10. One-step preparation of metal-free phthalocyanine with controllable crystal form
  11. In vitro and in vivo applications of Euphorbia wallichii shoot extract-mediated gold nanospheres
  12. Fabrication of green ZnO nanoparticles using walnut leaf extract to develop an antibacterial film based on polyethylene–starch–ZnO NPs
  13. Preparation of Zn-MOFs by microwave-assisted ball milling for removal of tetracycline hydrochloride and Congo red from wastewater
  14. Feasibility of fly ash as fluxing agent in mid- and low-grade phosphate rock carbothermal reduction and its reaction kinetics
  15. Three combined pretreatments for reactive gasification feedstock from wet coffee grounds waste
  16. Biosynthesis and antioxidation of nano-selenium using lemon juice as a reducing agent
  17. Combustion and gasification characteristics of low-temperature pyrolytic semi-coke prepared through atmosphere rich in CH4 and H2
  18. Microwave-assisted reactions: Efficient and versatile one-step synthesis of 8-substituted xanthines and substituted pyrimidopteridine-2,4,6,8-tetraones under controlled microwave heating
  19. New approach in process intensification based on subcritical water, as green solvent, in propolis oil in water nanoemulsion preparation
  20. Continuous sulfonation of hexadecylbenzene in a microreactor
  21. Synthesis, characterization, biological activities, and catalytic applications of alcoholic extract of saffron (Crocus sativus) flower stigma-based gold nanoparticles
  22. Foliar applications of plant-based titanium dioxide nanoparticles to improve agronomic and physiological attributes of wheat (Triticum aestivum L.) plants under salinity stress
  23. Simultaneous leaching of rare earth elements and phosphorus from a Chinese phosphate ore using H3PO4
  24. Silica extraction from bauxite reaction residue and synthesis water glass
  25. Metal–organic framework-derived nanoporous titanium dioxide–heteropoly acid composites and its application in esterification
  26. Highly Cr(vi)-tolerant Staphylococcus simulans assisting chromate evacuation from tannery effluent
  27. A green method for the preparation of phoxim based on high-boiling nitrite
  28. Silver nanoparticles elicited physiological, biochemical, and antioxidant modifications in rice plants to control Aspergillus flavus
  29. Mixed gel electrolytes: Synthesis, characterization, and gas release on PbSb electrode
  30. Supported on mesoporous silica nanospheres, molecularly imprinted polymer for selective adsorption of dichlorophen
  31. Synthesis of zeolite from fly ash and its adsorption of phosphorus in wastewater
  32. Development of a continuous PET depolymerization process as a basis for a back-to-monomer recycling method
  33. Green synthesis of ZnS nanoparticles and fabrication of ZnS–chitosan nanocomposites for the removal of Cr(vi) ion from wastewater
  34. Synthesis, surface modification, and characterization of Fe3O4@SiO2 core@shell nanostructure
  35. Antioxidant potential of bulk and nanoparticles of naringenin against cadmium-induced oxidative stress in Nile tilapia, Oreochromis niloticus
  36. Variability and improvement of optical and antimicrobial performances for CQDs/mesoporous SiO2/Ag NPs composites via in situ synthesis
  37. Green synthesis of silver nanoparticles: Characterization and its potential biomedical applications
  38. Green synthesis, characterization, and antimicrobial activity of silver nanoparticles prepared using Trigonella foenum-graecum L. leaves grown in Saudi Arabia
  39. Intensification process in thyme essential oil nanoemulsion preparation based on subcritical water as green solvent and six different emulsifiers
  40. Synthesis and biological activities of alcohol extract of black cumin seeds (Bunium persicum)-based gold nanoparticles and their catalytic applications
  41. Digera muricata (L.) Mart. mediated synthesis of antimicrobial and enzymatic inhibitory zinc oxide bionanoparticles
  42. Aqueous synthesis of Nb-modified SnO2 quantum dots for efficient photocatalytic degradation of polyethylene for in situ agricultural waste treatment
  43. Study on the effect of microwave roasting pretreatment on nickel extraction from nickel-containing residue using sulfuric acid
  44. Green nanotechnology synthesized silver nanoparticles: Characterization and testing its antibacterial activity
  45. Phyto-fabrication of selenium nanorods using extract of pomegranate rind wastes and their potentialities for inhibiting fish-borne pathogens
  46. Hydrophilic modification of PVDF membranes by in situ synthesis of nano-Ag with nano-ZrO2
  47. Paracrine study of adipose tissue-derived mesenchymal stem cells (ADMSCs) in a self-assembling nano-polypeptide hydrogel environment
  48. Study of the corrosion-inhibiting activity of the green materials of the Posidonia oceanica leaves’ ethanolic extract based on PVP in corrosive media (1 M of HCl)
  49. Callus-mediated biosynthesis of Ag and ZnO nanoparticles using aqueous callus extract of Cannabis sativa: Their cytotoxic potential and clinical potential against human pathogenic bacteria and fungi
  50. Ionic liquids as capping agents of silver nanoparticles. Part II: Antimicrobial and cytotoxic study
  51. CO2 hydrogenation to dimethyl ether over In2O3 catalysts supported on aluminosilicate halloysite nanotubes
  52. Corylus avellana leaf extract-mediated green synthesis of antifungal silver nanoparticles using microwave irradiation and assessment of their properties
  53. Novel design and combination strategy of minocycline and OECs-loaded CeO2 nanoparticles with SF for the treatment of spinal cord injury: In vitro and in vivo evaluations
  54. Fe3+ and Ce3+ modified nano-TiO2 for degradation of exhaust gas in tunnels
  55. Analysis of enzyme activity and microbial community structure changes in the anaerobic digestion process of cattle manure at sub-mesophilic temperatures
  56. Synthesis of greener silver nanoparticle-based chitosan nanocomposites and their potential antimicrobial activity against oral pathogens
  57. Baeyer–Villiger co-oxidation of cyclohexanone with Fe–Sn–O catalysts in an O2/benzaldehyde system
  58. Increased flexibility to improve the catalytic performance of carbon-based solid acid catalysts
  59. Study on titanium dioxide nanoparticles as MALDI MS matrix for the determination of lipids in the brain
  60. Green-synthesized silver nanoparticles with aqueous extract of green algae Chaetomorpha ligustica and its anticancer potential
  61. Curcumin-removed turmeric oleoresin nano-emulsion as a novel botanical fungicide to control anthracnose (Colletotrichum gloeosporioides) in litchi
  62. Antibacterial greener silver nanoparticles synthesized using Marsilea quadrifolia extract and their eco-friendly evaluation against Zika virus vector, Aedes aegypti
  63. Optimization for simultaneous removal of NH3-N and COD from coking wastewater via a three-dimensional electrode system with coal-based electrode materials by RSM method
  64. Effect of Cu doping on the optical property of green synthesised l-cystein-capped CdSe quantum dots
  65. Anticandidal potentiality of biosynthesized and decorated nanometals with fucoidan
  66. Biosynthesis of silver nanoparticles using leaves of Mentha pulegium, their characterization, and antifungal properties
  67. A study on the coordination of cyclohexanocucurbit[6]uril with copper, zinc, and magnesium ions
  68. Ultrasound-assisted l-cysteine whole-cell bioconversion by recombinant Escherichia coli with tryptophan synthase
  69. Green synthesis of silver nanoparticles using aqueous extract of Citrus sinensis peels and evaluation of their antibacterial efficacy
  70. Preparation and characterization of sodium alginate/acrylic acid composite hydrogels conjugated to silver nanoparticles as an antibiotic delivery system
  71. Synthesis of tert-amylbenzene for side-chain alkylation of cumene catalyzed by a solid superbase
  72. Punica granatum peel extracts mediated the green synthesis of gold nanoparticles and their detailed in vivo biological activities
  73. Simulation and improvement of the separation process of synthesizing vinyl acetate by acetylene gas-phase method
  74. Review Articles
  75. Carbon dots: Discovery, structure, fluorescent properties, and applications
  76. Potential applications of biogenic selenium nanoparticles in alleviating biotic and abiotic stresses in plants: A comprehensive insight on the mechanistic approach and future perspectives
  77. Review on functionalized magnetic nanoparticles for the pretreatment of organophosphorus pesticides
  78. Extraction and modification of hemicellulose from lignocellulosic biomass: A review
  79. Topical Issue: Recent advances in deep eutectic solvents: Fundamentals and applications (Guest Editors: Santiago Aparicio and Mert Atilhan)
  80. Delignification of unbleached pulp by ternary deep eutectic solvents
  81. Removal of thiophene from model oil by polyethylene glycol via forming deep eutectic solvents
  82. Valorization of birch bark using a low transition temperature mixture composed of choline chloride and lactic acid
  83. Topical Issue: Flow chemistry and microreaction technologies for circular processes (Guest Editor: Gianvito Vilé)
  84. Stille, Heck, and Sonogashira coupling and hydrogenation catalyzed by porous-silica-gel-supported palladium in batch and flow
  85. In-flow enantioselective homogeneous organic synthesis
https://doi.org/10.1515/gps-2021-0033
Schlagwörter für diesen Artikel
mixed gel electrolyte; additives; ionic conductivity; diffusion coefficient; gas release
Creative Commons
BY 4.0

Artikel in diesem Heft

  1. Research Articles
  2. MW irradiation and ionic liquids as green tools in hydrolyses and alcoholyses
  3. Effect of CaO on catalytic combustion of semi-coke
  4. Studies of Penicillium species associated with blue mold disease of grapes and management through plant essential oils as non-hazardous botanical fungicides
  5. Development of leftover rice/gelatin interpenetrating polymer network films for food packaging
  6. Potent antibacterial action of phycosynthesized selenium nanoparticles using Spirulina platensis extract
  7. Green synthesized silver and copper nanoparticles induced changes in biomass parameters, secondary metabolites production, and antioxidant activity in callus cultures of Artemisia absinthium L.
  8. Gold nanoparticles from Celastrus hindsii and HAuCl4: Green synthesis, characteristics, and their cytotoxic effects on HeLa cells
  9. Green synthesis of silver nanoparticles using Tropaeolum majus: Phytochemical screening and antibacterial studies
  10. One-step preparation of metal-free phthalocyanine with controllable crystal form
  11. In vitro and in vivo applications of Euphorbia wallichii shoot extract-mediated gold nanospheres
  12. Fabrication of green ZnO nanoparticles using walnut leaf extract to develop an antibacterial film based on polyethylene–starch–ZnO NPs
  13. Preparation of Zn-MOFs by microwave-assisted ball milling for removal of tetracycline hydrochloride and Congo red from wastewater
  14. Feasibility of fly ash as fluxing agent in mid- and low-grade phosphate rock carbothermal reduction and its reaction kinetics
  15. Three combined pretreatments for reactive gasification feedstock from wet coffee grounds waste
  16. Biosynthesis and antioxidation of nano-selenium using lemon juice as a reducing agent
  17. Combustion and gasification characteristics of low-temperature pyrolytic semi-coke prepared through atmosphere rich in CH4 and H2
  18. Microwave-assisted reactions: Efficient and versatile one-step synthesis of 8-substituted xanthines and substituted pyrimidopteridine-2,4,6,8-tetraones under controlled microwave heating
  19. New approach in process intensification based on subcritical water, as green solvent, in propolis oil in water nanoemulsion preparation
  20. Continuous sulfonation of hexadecylbenzene in a microreactor
  21. Synthesis, characterization, biological activities, and catalytic applications of alcoholic extract of saffron (Crocus sativus) flower stigma-based gold nanoparticles
  22. Foliar applications of plant-based titanium dioxide nanoparticles to improve agronomic and physiological attributes of wheat (Triticum aestivum L.) plants under salinity stress
  23. Simultaneous leaching of rare earth elements and phosphorus from a Chinese phosphate ore using H3PO4
  24. Silica extraction from bauxite reaction residue and synthesis water glass
  25. Metal–organic framework-derived nanoporous titanium dioxide–heteropoly acid composites and its application in esterification
  26. Highly Cr(vi)-tolerant Staphylococcus simulans assisting chromate evacuation from tannery effluent
  27. A green method for the preparation of phoxim based on high-boiling nitrite
  28. Silver nanoparticles elicited physiological, biochemical, and antioxidant modifications in rice plants to control Aspergillus flavus
  29. Mixed gel electrolytes: Synthesis, characterization, and gas release on PbSb electrode
  30. Supported on mesoporous silica nanospheres, molecularly imprinted polymer for selective adsorption of dichlorophen
  31. Synthesis of zeolite from fly ash and its adsorption of phosphorus in wastewater
  32. Development of a continuous PET depolymerization process as a basis for a back-to-monomer recycling method
  33. Green synthesis of ZnS nanoparticles and fabrication of ZnS–chitosan nanocomposites for the removal of Cr(vi) ion from wastewater
  34. Synthesis, surface modification, and characterization of Fe3O4@SiO2 core@shell nanostructure
  35. Antioxidant potential of bulk and nanoparticles of naringenin against cadmium-induced oxidative stress in Nile tilapia, Oreochromis niloticus
  36. Variability and improvement of optical and antimicrobial performances for CQDs/mesoporous SiO2/Ag NPs composites via in situ synthesis
  37. Green synthesis of silver nanoparticles: Characterization and its potential biomedical applications
  38. Green synthesis, characterization, and antimicrobial activity of silver nanoparticles prepared using Trigonella foenum-graecum L. leaves grown in Saudi Arabia
  39. Intensification process in thyme essential oil nanoemulsion preparation based on subcritical water as green solvent and six different emulsifiers
  40. Synthesis and biological activities of alcohol extract of black cumin seeds (Bunium persicum)-based gold nanoparticles and their catalytic applications
  41. Digera muricata (L.) Mart. mediated synthesis of antimicrobial and enzymatic inhibitory zinc oxide bionanoparticles
  42. Aqueous synthesis of Nb-modified SnO2 quantum dots for efficient photocatalytic degradation of polyethylene for in situ agricultural waste treatment
  43. Study on the effect of microwave roasting pretreatment on nickel extraction from nickel-containing residue using sulfuric acid
  44. Green nanotechnology synthesized silver nanoparticles: Characterization and testing its antibacterial activity
  45. Phyto-fabrication of selenium nanorods using extract of pomegranate rind wastes and their potentialities for inhibiting fish-borne pathogens
  46. Hydrophilic modification of PVDF membranes by in situ synthesis of nano-Ag with nano-ZrO2
  47. Paracrine study of adipose tissue-derived mesenchymal stem cells (ADMSCs) in a self-assembling nano-polypeptide hydrogel environment
  48. Study of the corrosion-inhibiting activity of the green materials of the Posidonia oceanica leaves’ ethanolic extract based on PVP in corrosive media (1 M of HCl)
  49. Callus-mediated biosynthesis of Ag and ZnO nanoparticles using aqueous callus extract of Cannabis sativa: Their cytotoxic potential and clinical potential against human pathogenic bacteria and fungi
  50. Ionic liquids as capping agents of silver nanoparticles. Part II: Antimicrobial and cytotoxic study
  51. CO2 hydrogenation to dimethyl ether over In2O3 catalysts supported on aluminosilicate halloysite nanotubes
  52. Corylus avellana leaf extract-mediated green synthesis of antifungal silver nanoparticles using microwave irradiation and assessment of their properties
  53. Novel design and combination strategy of minocycline and OECs-loaded CeO2 nanoparticles with SF for the treatment of spinal cord injury: In vitro and in vivo evaluations
  54. Fe3+ and Ce3+ modified nano-TiO2 for degradation of exhaust gas in tunnels
  55. Analysis of enzyme activity and microbial community structure changes in the anaerobic digestion process of cattle manure at sub-mesophilic temperatures
  56. Synthesis of greener silver nanoparticle-based chitosan nanocomposites and their potential antimicrobial activity against oral pathogens
  57. Baeyer–Villiger co-oxidation of cyclohexanone with Fe–Sn–O catalysts in an O2/benzaldehyde system
  58. Increased flexibility to improve the catalytic performance of carbon-based solid acid catalysts
  59. Study on titanium dioxide nanoparticles as MALDI MS matrix for the determination of lipids in the brain
  60. Green-synthesized silver nanoparticles with aqueous extract of green algae Chaetomorpha ligustica and its anticancer potential
  61. Curcumin-removed turmeric oleoresin nano-emulsion as a novel botanical fungicide to control anthracnose (Colletotrichum gloeosporioides) in litchi
  62. Antibacterial greener silver nanoparticles synthesized using Marsilea quadrifolia extract and their eco-friendly evaluation against Zika virus vector, Aedes aegypti
  63. Optimization for simultaneous removal of NH3-N and COD from coking wastewater via a three-dimensional electrode system with coal-based electrode materials by RSM method
  64. Effect of Cu doping on the optical property of green synthesised l-cystein-capped CdSe quantum dots
  65. Anticandidal potentiality of biosynthesized and decorated nanometals with fucoidan
  66. Biosynthesis of silver nanoparticles using leaves of Mentha pulegium, their characterization, and antifungal properties
  67. A study on the coordination of cyclohexanocucurbit[6]uril with copper, zinc, and magnesium ions
  68. Ultrasound-assisted l-cysteine whole-cell bioconversion by recombinant Escherichia coli with tryptophan synthase
  69. Green synthesis of silver nanoparticles using aqueous extract of Citrus sinensis peels and evaluation of their antibacterial efficacy
  70. Preparation and characterization of sodium alginate/acrylic acid composite hydrogels conjugated to silver nanoparticles as an antibiotic delivery system
  71. Synthesis of tert-amylbenzene for side-chain alkylation of cumene catalyzed by a solid superbase
  72. Punica granatum peel extracts mediated the green synthesis of gold nanoparticles and their detailed in vivo biological activities
  73. Simulation and improvement of the separation process of synthesizing vinyl acetate by acetylene gas-phase method
  74. Review Articles
  75. Carbon dots: Discovery, structure, fluorescent properties, and applications
  76. Potential applications of biogenic selenium nanoparticles in alleviating biotic and abiotic stresses in plants: A comprehensive insight on the mechanistic approach and future perspectives
  77. Review on functionalized magnetic nanoparticles for the pretreatment of organophosphorus pesticides
  78. Extraction and modification of hemicellulose from lignocellulosic biomass: A review
  79. Topical Issue: Recent advances in deep eutectic solvents: Fundamentals and applications (Guest Editors: Santiago Aparicio and Mert Atilhan)
  80. Delignification of unbleached pulp by ternary deep eutectic solvents
  81. Removal of thiophene from model oil by polyethylene glycol via forming deep eutectic solvents
  82. Valorization of birch bark using a low transition temperature mixture composed of choline chloride and lactic acid
  83. Topical Issue: Flow chemistry and microreaction technologies for circular processes (Guest Editor: Gianvito Vilé)
  84. Stille, Heck, and Sonogashira coupling and hydrogenation catalyzed by porous-silica-gel-supported palladium in batch and flow
  85. In-flow enantioselective homogeneous organic synthesis
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