The present work investigates the impact of SiO2 nanofiller on the electrochemical properties of gel polymer electrolytes (GPEs) composed of PMMA/PLA-LiBOB. The study encompasses two distinct systems: PMMA/PLA-LiBOB (System I) and PMMA/PLA-LiBOB-SiO2 (System II). Nyquist plots were generated to analyze the samples' bulk resistance (Rb), and it was found that Rb value shows a decreasing trend with the incorporation of SiO2. The ionic conductivity increases from 1.69×10-6 S cm-1 to 1.37×10-3 S cm-1 at room temperature, with the highest composition achieved at 6 wt.% of SiO2. Dielectric properties revealed that the addition of SiO2 nanofiller led to the enhancement of dielectric constant (ε′) and dielectric loss (ε″), attributed to SiO2 nanofiller with high orientation polarizability and space charge polarization effects. Linear Sweep Voltammetry (LSV) measurements from both GPE samples are 4.1 V (System I) and 4.7 V (System II). Comparative electrochemical performances of the batteries assembled in System I and System II were conducted, demonstrating the superiority of System II in terms of stability and cycling performance. The differential capacity analysis further supported the enhanced electrochemical activity upon SiO2 nanofiller incorporation.
Research Article
The improvement in electrochemical properties with the addition of SiO2 into PMMA/PLA-LiBOB Gel Polymer Electrolytes Based Lithium Ions Battery
https://doi.org/10.21203/rs.3.rs-4010574/v1
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Lithium-ion batteries
SiO2 nanofiller
gel polymer electrolyte
electrochemical properties
The Nobel Prize in Chemistry (given in 2019) recognised lithium-ion battery (LIB) technology as the foundation for a fossil-free global power source. Its highly appealing characteristics, such as superior energy density, power density, excellent rate capability, and long cycle life, have made it useful in a variety of devices, including portable electronics, electric vehicles, energy storage systems, robotics, military equipment, emergency systems, and medical devices [1-3]. Since its debut in 1991, modern LIBs have improved battery performance by improving energy density at a rate of 7-8 Wh/kg every year [4]. The prevalent concept of achieving "carbon neutrality" has fueled substantial research and development of lithium-ion batteries, which are the leading clean secondary battery technologies.
A noteworthy aspect of LIBs is the notable decrease in cost despite performance improvements, making them a dominant force in the consumer electronics market. A traditional lithium-ion battery (LIB) comprises key components: a cathode, an anode, a separator, and an electrolyte [5]. The primary role of the electrolyte is to facilitate the movement of lithium ions between the cathode and the anode [6]. The electrolyte is a critical constituent that can significantly impact the cycle stability, capacity, safety, and operational characteristics of LIBs [7]. Conventional LIBs typically employ liquid electrolytes (LEs), commonly consisting of lithium hexafluorophosphate (LiPF6) and organic carbonates. Among these carbonates, dimethyl carbonate (DMC) and diethyl carbonate (DEC) are known for their high volatility and flammability. Conventional LEs are considered to have explosive properties and it is essential to note that excessive heating of the batteries can trigger exothermal reactions, potentially leading to a thermal runaway. This dangerous situation releases substantial amounts of heat, gas emissions, and, in orst cases, fire or explosion/rapid disassembly [8]. Even without a thermal runaway event, a heated battery can still release flammable and toxic gases, posing significant safety risks. The liquid electrolytes used in these batteries are susceptible to leakage issues [9–11]. These issues have raised concerns about their widespread applications and caused historical recall issues with electronic gadgets that employ LIBs. Thus, ensuring the safety of the traditionally utilized liquid electrolyte (LE) is crucial to developing large-scale LIBs [12–14].
To address these issues, a promising technique includes undertaking extensive research and adopting polymer electrolytes [8]. This work aims to develop a more secure electrochemical mechanism for LIBs, providing potential solutions to the hazards associated with conventional liquid electrolytes while maintaining the battery's ideal performance. Gel polymer electrolytes (GPEs), also known as quasi-solid-state electrolytes, exist in an intermediate state between solid and liquid. These electrolytes are made by immersing a polymer film in a liquid electrolyte, producing good ionic conductivity at ambient temperature and outstanding safety comparable to solid electrolytes [15-19]. Notably, GPEs are flexible and may conform to electrodes, reducing interfacial resistance. Polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), polymethylmethacrylate (PMMA), and polyvinyl chloride (PVC) have all been used as GPE matrix materials [20].
Despite their numerous advantages, gel polymer electrolytes exhibited poor mechanical properties and limited thermal stability. As a result, a practical approach entails the creation of inorganic/polymer composite electrolytes that combine the properties of both inorganic and polymer materials. Incorporating inorganic fillers such as SiO2, TiO2, ZnO, and graphene into the polymer matrix has previously been shown to have several beneficial effects [21-23]. The increased proportion of amorphous regions in the polymer chain results in a reduction in the overall crystallinity of the polymer films, which is a significant advantage. This improves the migration number of Li ions (Li+) and increases ionic conductivity within the composite gel polymer electrolytes (GPEs). Furthermore, the inorganic fillers have a high heat resistance, resulting in a significant improvement in the thermal stability of the composited GPEs. This feature is significant for ensuring battery safety and reliability because it helps prevent thermal runaway and other hazards. In addition, the addition of inorganic nanofillers improves the mechanical strength and interfacial stability of the GPEs [24-26]. This improvement improves the battery's mechanical integrity and promotes a more secure interface between the polymer electrolyte and the electrode materials.
As a continuation of our previous research [27], we demonstrated the incorporation of SiO2 nanofiller into poly (methyl methacrylate) (PMMA) and poly (lactic acid) (PLA) blends doped with lithium bis(oxalate) borate in this study. We investigate the electrochemical properties of the resulting GPEs and put the best ionic conducting sample to the test in coin-type LIBs. The electrochemical performance of these LIBs was then evaluated regarding charge-discharge characteristics and cyclic capability. GPE systems without incorporating SiO2 nanofiller were also subjected to electrochemical performances in LIBs for comparison studies.
Sample preparation
The materials utilized in the present study comprise PMMA (molecular weight 996,000 g/mol; Aldrich Co.), PLA (molecular weight 1,200,000 g/mol; Shandong Zhi Shang Chemical Co. LTD), LiBOB (Aldrich Co.), and SiO2 (Sigma Aldrich Co.). The schematic depiction in Figure 1 illustrates the process of preparing GPEs for System I (PMMA/PLA-LiBOB) and System II (PMMA/PLA-LiBOB-SiO2). Initially, 0.04 g of PLA was dissolved in 0.8 ml of triethylene glycol dimethyl ether (TEGDME) at 130°C. Subsequently, upon achieving a clear solution, it was allowed to cool to room temperature before introducing varying compositions of LiBOB salts (ranging from 5 wt.% to 30 wt.%) for System I. Based on previous investigations, samples containing 20 wt.% LiBOB demonstrated superior electrical properties compared to others. Hence, this composition was selected for the formulation of System II, with the addition of varying amounts of SiO2 (ranging from 2 wt.% to 12 wt.%). The solution was continuously stirred until complete dissolution. Finally, 0.16 g of PMMA was incorporated into the solution, stirring at 70°C until a gel-like consistency was achieved. Subsequently, the GPE samples were subjected to vacuum treatment to eliminate moisture and stored under an Argon atmosphere to preserve ambient conditions before subsequent analyses.
Characterization
Electrical Impedance Spectroscopy (EIS)
The Electrical Impedance Spectroscopy (EIS) technique is widely recognized for its versatility, allowing for examining materials at different frequencies. In this study, we conducted EIS measurements using a computer-interfaced HIOKI IM 3352 LCR METER in a frequency range from 50 Hz to 1 MHz. The temperature during the measurements was controlled between 30 °C to 120 °C. In this study, a voltage of 10 mV was applied. The samples were placed between two stainless steel blocking electrodes to perform the EIS measurements. The EIS measurements enabled us to measure the real and imaginary parts of the complex impedance at various frequencies, providing valuable insights into the electrical behavior of the studied materials.
Linear sweep voltammetry (LSV)
After identifying the optimal samples from the Electrochemical Impedance Spectroscopy (EIS) measurements in System I and System II, further characterization was conducted through Linear Sweep Voltammetry (LSV) analysis. The characterization used a C-H instrument (model 600E) potentiostat to assess electrochemical stability under ambient temperature conditions. During the LSV testing, a two-electrode system was utilized, where the stainless-steel electrode functioned as the working electrode. At the same time, the lithium metal served as the reference and counter electrodes. A scan rate of 10 mV/s was chosen for the LSV measurements to assess the electrochemical performance. This scan rate allows us to record the variation of current density concerning voltage in a controlled manner. By plotting the current density against voltage, we can extract valuable information about the maximum voltage the samples can withstand without adverse effects. Overall, the LSV characterization provides crucial insights into the stability and performance of the most optimal GPE samples in both System I and System II, aiding in evaluating their potential suitability for practical applications in lithium-ion batteries.
Preparation of Lithium-ion batteries
Anode electrode
The primary focus of this study was to fabricate a half-cell battery, and consequently, the graphite anode was chosen as the electrode for both System I and System II. Materials were utilized in the electrode fabrication process, including activated carbon (TimRex KS6 Graphite), super P, polyvinylidene fluoride (PVdF), and N-methyl-2-pyrrolidone (NMP). The graphite served as the active material, while the super P functioned as the conductive material, PVDF acted as the binding agent, and NMP played the role of the solvent. A ratio of 80:10:10 of activated carbon to super P to PVdF was used to achieve the desired electrode composition, resulting in a total weight of 0.5 g. The preparation involved grounding the super P and active material using a mortar and pestle until a thorough mixture was obtained. Subsequently, the mixture of super P and active material were heated in a vacuum oven at 80°C for 1 hour. Then, 1.0 mL of NMP was pipetted into the PVdF and stirred until a homogeneous solution was formed. The mixture underwent sonication for 10 minutes, after which the mixture of super P and active material was added. Another 1.0 mL of NMP was pipetted into the solution, and stirring continued until a homogeneous mixture was achieved. Using doctor blade technique, the resulting anode slurry was coated onto copper foil, acting as the current collector. The coated foils were heated in a vacuum oven at 80°C for 1 hour and left under vacuum conditions for 1 day to reduce moisture. The electrodes were then calendared and punched to attain the desired shape and consistency. Figure 2 shows the schematic presentation of electrode preparation for both systems.
Fabrication of coin cell
Figure 3 (a) illustrates the graphite electrode after being coated with the electrolyte for both systems, showcasing the successful application of the technique. Before the coin cell assembly, the graphite electrode was coated with the GPEs. This approach aimed to establish an efficient interface between the electrode and electrolyte, facilitating unhindered ion transport within the battery. The graphite electrode underwent a coating process with the prepared electrolytes for System I and System II. This procedure involved heating the coated electrode at 60°C for approximately 1 hour. The cell configuration is Li metalǀelectrolyteǀgraphite, and the optimum conducting samples from both systems have been used as an electrolyte. The cells were fabricated within an argon-filled glove box to maintain a controlled and inert environment. Figure 3 (b) visually represents the LIBs components, demonstrating the successful construction of the battery cells.
Galvanostatic Charge Discharge (GCD)
The charge-discharge performance of the lithium-ion batteries (LIBs) in both System I and System II was meticulously characterized using a galvanostatic NEWARE battery tester machine. The NEWARE Battery Tester System (BTS) software was employed to assess the electrochemical performance, which enabled precise control and monitoring during the charging and discharging processes. During the discharging phase, the LIBs were subjected to the NEWARE Battery Tester System, with cut-off voltages ranging from 0.01 V to 2.0 V. Various charge/discharge current densities were applied, which are 3.72 A/g, 11.16 A/g, 18.60 A/g and 26.04 A/g. These current densities were carefully selected to evaluate the battery's performance under different charging and discharging conditions. The entire charge-discharge process was conducted under ambient conditions, ensuring the batteries were tested in a standard environment representative of practical usage scenarios. This approach allowed for an accurate and reliable assessment on the performance of LIBs and behaviour during the charging and discharging cycles.
Conduction mechanisms
Figure 4 depicts the hypothesised interaction mechanism between polymer matrices, ionic dopants, and nanofillers. Initially, in pure polymer-salt complexes, such as those involving LiBOB, the salt dissociates, releasing free ions. These cations solvate by interacting with polar coordination sites in the polymer matrix, particularly oxygen (O) atoms. Meanwhile, the anions spread throughout the polymeric matrix or align with the polymer's chain ends. Lithium ions coordinate with oxygen atoms via ion-dipole interactions, as shown in Figure 4. (a). These ions then engage in hopping mechanisms, moving into nearby polar groups.
With the addition of nanofillers, specifically SiO2 particles, which feature hydroxyl groups on their surfaces, potential interactions arise between these particles and oxygen atoms from the polymer matrix or BOB- anions within the polymer matrices. These interactions can occur through hydrogen bonding or Van der Waals forces, as Figure 4 (b) depicts. Enhanced dispersion and compatibility between the polymer matrix and nanoparticles can result from these interactions, thus bolstering the stability of the electrolyte system. Moreover, the electron-deficient sites on the SiO2 nanoparticles' surface may engage with electron-rich sites of the polymer complexes, forming Lewis acid-base interactions. This interaction can lead to the formation of complexes between nanoparticles and polymer complexes, thereby influencing the electrolyte's overall structure and properties. Additionally, nanofillers may serve as bridges between adjacent polymer matrices, as depicted in Figure 4 (c). This bridging facilitates additional pathways for ion transport, notably for Li⁺ ions, enhancing ion transport properties. Consequently, the movement of Li⁺ ions is facilitated, contributing to an overall improvement in ion transport within the system.
To study the influence of SiO2 nanofiller on the electrical characteristics of the PMMA/PLA-LiBOB as indicated in Fig. 4, Nyquist plots were created, illustrating the real (Z') and imaginary (Z") components of the impedance, as shown in Figure 5. From the Nyquist plots displayed in Figure 5, the intercept of the semicircles on the real axis (x-axis) provides valuable information about the bulk resistance () of the electrolytes under investigation. As depicted in the plots, it is evident that the exhibits a decreasing trend with the incorporation of SiO2 nanofiller. The observed decreasing trend in bulk resistance signifies an improvement in the number of charge carriers and the mobility of ions within the system [28]. The dispersed nanofiller has the potential to induce specific structural modifications through Lewis acid-base reactions between its surface characteristics and the segments of PMMA/PLA polymers. It is conceivable that the Lewis acid groups present on the surface of the filler may compete with Lewis acid Li+ cations to form complexes with both the polymer chains and the anions from the introduced LiBOB salt. These outcomes could result in localized structural changes on the surface of the nanofiller. The cations originating from the polar surface groups of the nanofiller may serve dual roles: firstly, acting as cross-linking centers for polymer segments, thereby reducing the probability of polymer reorganization and supporting structural alterations in the polymer chains. This is expected to enhance the pathways for Li+ conduction at the nanofiller's surface, leading to improved ionic conductivity. Secondly, serving as centers for Lewis acid-base interactions with ionic species in the electrolyte. This is anticipated to reduce ionic coupling, facilitating salt dissociation through the formation of ion-filler complexes, ultimately enhancing the transport of Li+ ions [29]. Table 1 shows the value of bulk resistance for both systems.
In this study, we investigated the dielectric properties of the prepared PMMA/PLA-20 wt.% LiBOB and PMMA/PLA-LiBOB-6 wt.% SiO2 GPEs system to assess their suitability for use in LIBs. The dielectric properties were evaluated by analysing both the dielectric constant (ε′) and the dielectric loss (ε″). The dielectric constant provides insights into the material's ability to store energy, while the dielectric loss measures the amount of energy dissipated within the material during the process [30,31]. Figures 6 (a) and (b) display both systems' dielectric constant and loss, respectively. The PMMA/PLA-LiBOB-6 wt.% SiO2 GPEs sample that were prepared demonstrated noticeable improvements in the values of both dielectric constant (ε′) and dielectric loss (ε″) when compared to the prepared PMMA/PLA-20 wt.% LiBOB GPEs system. This enhancement in dielectric properties can be attributed to the presence of SiO2 nanofiller in the nanocomposite films. Previous studies have reported that NPs possess high orientation polarizability [32].
Moreover, the improvements in ε′ and ε″ could also be linked to the accumulation of charges at the grain boundaries of the SiO2 nanofiller, leading to the creation of space charge polarization within the nanocomposites. This phenomenon further contributes to the enhancement of dielectric properties [33]. Besides that, it is worth noting that the values of dielectric constant (ε′) and dielectric loss (ε″) exhibit a rapid increase at lower frequencies due to the ability of dipoles in the nanocomposite film to easily align and follow the orientation of the applied electric field, which changes more slowly at lower frequencies. However, at higher frequencies, the applied electric field changes rapidly, causing the charge carriers in the nanocomposite GPE to be unable to keep up with the rapid changes in the electric field. Consequently, this results in lower values of both dielectric constants and dielectric losses at high frequencies [34]. In the conclusion drawn from the dielectric properties analysis, it was observed that the values of dielectric constant (ε′) and dielectric loss (ε″) increased with the incorporation of SiO2 nanofiller in the nanocomposite GPE. This phenomenon can be attributed to the accumulation of free charge carriers at the interfaces between the electrodes and the nanocomposite samples [35].
Linear Sweep Voltammetry (LSV)
The electrochemical stability window of the electrolytes in this system was determined through Linear Sweep Voltammetry (LSV) measurements. LSV is a technique employed to ascertain the decomposition voltage of the electrolyte, which corresponds to the highest operating voltage at which the electrochemical device remains stable and the electrolyte can be safely applied. Figure 7 illustrates the linear sweep voltammetry plot for GPEs with varying nanofiller compositions, specifically 0 wt.% and 6 wt.%. Upon applying a voltage sweep at a rate of 10 mV/s, starting from 2.9 V and progressing onward, there is a notable abrupt surge in current. This phenomenon is attributed to the electrolyte decomposition occurring at the interface of the inert electrode [36]. When comparing the decomposition voltages between GPEs containing 0 wt.% and 6 wt.% nanofillers, denoted as System I and System II, respectively, a significant disparity in voltage stability becomes evident. System II exhibits a decomposition voltage of 4.7 V, a notably higher value than the 4.1 V exhibited by nanofiller-free GPEs samples. This discovery aligns with the investigation conducted by Borah et al., wherein it was observed that the potential voltage increased from 4.2 V to 4.7 V upon the incorporation of SiO2 nanofillers [37]. Incorporating nanofillers initiates a robust interaction between the hydroxyl groups at the surface of SiO2 nanofiller and the matrices of PMMA/PLA, consequently amplifying their electrochemical stability. The Lewis acid sites present on the surface of the nanofiller engage with the Lewis base (BOB-), impeding the decomposition of lithium salt anions, thereby ultimately elevating the electrochemical potential window [38][38]. Consequently, System II displays an improved electrochemical potential window compared to the nanofiller-free samples. Lithium-ion rechargeable batteries typically operate within a working potential range of 1.8 V to 3.5 V versus Li+/Li [39]. Therefore, the broad electrochemical window observed in both systems suits their application in lithium-ion batteries.
Galvanostatic Charge Discharge (GCD)
The most conductive samples from System I-PMMA/PLA-20 wt.% LiBOB and System II-PMMA/PLA-LiBOB-6 wt.% SiO2 were chosen to fabricate lithium-ion batteries. The electrochemical performances of these batteries were then compared to assess the influence of incorporating SiO2 nanofillers in the respective systems. This comparison aimed to gain a deeper understanding of the effects of SiO2 nanofiller inclusion on the overall performance of the batteries. Figure 8 (a) shows the charge-discharge analysis for System I for every 20th cycle at the current density of 3.72 A/g. The figure shows that the discharge capacity of the GPEs is 98 and 58 mAh/g for first and 20th cycles, respectively. It could be due to the phenomenon may be exacerbated by the loss of contact between the anode and the current collector [40]. Meanwhile, Figure 8 (b) shows the charge-discharge analysis for System II. Based on the figure, it is evident that the initial discharge capacity of System II is approximately 140 mAh/g, which represents a significant increase compared to the initial discharge capacity of System I. These findings suggest that the initial charge and discharge-specific capacities are enhanced in System II due to the battery's increased Li+ ionic conductivity and reduced cell resistance.
Throughout the cycles, the capacity of System II exhibits a slower decrease when compared to System I, indicating that System II demonstrates more stable cycle performances and improved cycling stability. These observations emphasize the favourable characteristics of System II, making it a promising candidate for applications requiring reliable and long-lasting battery performance. The introduction of SiO2 into the PMMA/PLA-LiBOB GPEs system has introduced a novel pathway that enhances ion transport within the system. This augmentation facilitates a more conductive route for ion flow. Additionally, SiO2 possesses an amorphous nature, which disrupts the crystalline structure within the systems, as depicted in Figure 9. This disruption increases the amorphous character of the systems, thereby enhancing the mobility of ions from the anode to the cathode and subsequently improving their electrochemical properties.
The decline of the discharge capacity of System I and System II can be proved through the cell resistance study, as evident in the analysis shown in Figure 10. The cell resistance progressively increased with each cycle for both systems. Following multiple cycles, the reduced conductivity becomes a challenge for the cell, impeding the rapid movement of ions within the electrolyte. The increased resistance within the electrolyte, leads to elevated ohmic losses and, subsequently, higher voltage drops. This, in turn, hastens the attainment of the lower cutoff voltage, resulting in an overall decrease in the cell's capacity [41].
The rate behaviors of the lithium-ion batteries assembled using PMMA/PLA-LiBOB and PMMA/PLA-LiBOB-SiO2 are presented in Figure 11. The capacity of the batteries is found to be comparable. However, the cell assembled with System II (PMMA/PLA-LiBOB-SiO2) exhibited a better initial capacity due to its higher ionic conductivity than System II. The increasing capacity implies that the integration of SiO2 nanofillers augments ion channels, establishing more interconnected network of ion channels, particularly at the interface between the electrode and electrolyte [42]. The introduction of SiO2 nanofillers contributes to improved interfacial characteristics and compatibility with the lithium electrode, thereby substantially enhancing the electrochemical performance of Cell in System II [43]. The decrease in capacity as current density rises is a notable observation in both systems. This decline in charge-discharge capacity is primarily attributed to the slower process of lithiation of the electrode at higher current densities [44]. In simpler terms, the increase in current density hampers the ability of the electrode to absorb lithium ions efficiently, resulting in diminished capacity and efficiency. This challenge predominantly stems from the aging of the anode electrode and is a well-acknowledged issue in lithium-ion batteries (LIBs). These factors collectively contribute to the depletion of active lithium within the battery system [45].
Despite this discrepancy in capacity, both systems still demonstrate promising potential for various electrochemical applications, and the results shed light on the importance of ionic conductivity and structural considerations in designing high-performance lithium-ion batteries. Introducing SiO2 nanofillers into the GPEs yields noteworthy enhancements in electrochemical stability. The incorporation of SiO2 nanofillers strengthens the composite membrane mechanically, thereby mitigating structural degradation and bolstering the electrolyte's stability throughout the cycling process. Also, the presence of SiO2 nanofillers contributes to elevated ionic conductivity within the composite membrane, facilitating more efficient ion transport. Consequently, the proliferation of Li dendrites, which could result in capacity fading and safety concerns, is effectively suppressed [46]. These positive outcomes highlight the valuable role of SiO2 nanofillers in improving the overall performance and safety of the solid polymer electrolyte system.
Figure 11 displays the differential capacity analysis, specifically the dQ/dV plots, during the first cycle at the current density of 3.72 A/g. These dQ/dV plots are derived from the raw time series current and voltage data from the charge-discharge measurement. In both battery systems, we observed three distinct and clearly defined Li intercalation/deintercalation redox reactions occurring at voltage ranges of 0.05/0.12 V, 0.09/0.16 V, and 0.17/0.24 V. These voltage ranges correspond to well-known phase transformation processes between dilute Stages 1 and 4, Stages 2 and 3, and Stages 2 and 1, respectively. As reported in prior research, t dQ/dV curves closely resemble the standard dQ/dV curve associated with graphite's Li-ion intercalation process [45–47]. The dQ/dV curves play a crucial role in assessing the electrochemical property, with the intensity of the anodic and cathodic peaks serving as significant parameters. High peak intensity indicates favourable electrochemical performance, signifying efficient charge and discharge processes [47]. Notably, upon incorporating SiO2 nanofillers, an evident increase in peak intensity is observed, indicating a marked improvement in electrochemical activity. This enhancement in peak intensity signifies a more efficient electrochemical reaction and highlights the beneficial impact of incorporating SiO2 nanofillers on the system's overall performance. The heightened electrochemical activity can be attributed to the enhanced ionic conductivity and improved stability from SiO2 nanofillers in the solid polymer electrolyte. These findings affirm the positive role of SiO2 nanofillers in bolstering the electrochemical properties of the system, making it a promising candidate for advanced energy storage applications.
In conclusion, incorporating SiO2 nanofillers in PMMA/PLA-LiBOB gel polymer electrolytes (GPEs) has significantly enhanced their electrical and electrochemical properties, rendering them promising candidates for lithium-ion battery (LIB) applications. SiO2 nanofillers contribute to decreased bulk resistance, indicating improved charge carrier mobility. The presence of SiO2 nanofillers also results in enhanced dielectric constant and dielectric loss, attributed to their high orientation polarizability and space charge polarization effects. The wide electrochemical window observed in both systems confirms their suitability for stable LIB operation. The batteries made with PMMA/PLA-LiBOB-SiO2 GPEs (System II) were more stable and had better cycling performance, and the growth of Li dendrites was slowed down. The differential capacity analysis further supported the enhanced electrochemical activity upon incorporating SiO2 nanofillers. The results show that SiO2 nanofillers might improve the safety and performance of solid polymer electrolyte systems. This could lead to new ways to store energy.
Acknowledgment
The authors thank Universiti Malaysia Pahang Al-Sultan Abdullah (UMPSA) for providing financial support under UMPSA International Publication Grant (RDU 223304), Faculty of Industrial Sciences and Technology, UMPSA and Centre for Ionics University of Malaya for the laboratory facilities for the completion of this work.
Funding
The present work was funded by Universiti Malaysia Pahang Al-Sultan Abdullah under UMPSA International Publication Grant (RDU 223304)
Author contributions
N.M. Khan: Draft preparation, Methodology, Investigation, Writing and Editing. M.Z. Kufian: Co-supervision, Data analysis, Writing - Review & Editing A.S. Samsudin: Reviewing, Validation, Conceptualization, Funding, Supervision, and Visualization.
Conflict of interest
There is no conflict of interest to declare.
- J. Guo, Y. Chen, Y. Xiao, C. Xi, G. Xu, B. Li, C. Yang, Y. Yu, Flame-retardant composite gel polymer electrolyte with a dual acceleration conduction mechanism for lithium ion batteries, Chemical Engineering Journal 422 (2021) 130526. https://doi.org/10.1016/J.CEJ.2021.130526.
- S. Wang, L. Zhou, M.K. Tufail, L. Yang, P. Zhai, R. Chen, W. Yang, In-Situ synthesized Non-flammable gel polymer electrolyte enable highly safe and Dendrite-Free lithium metal batteries, Chemical Engineering Journal 415 (2021) 128846. https://doi.org/10.1016/J.CEJ.2021.128846.
- X. Guan, Q. Wu, X. Zhang, X. Guo, C. Li, J. Xu, In-situ crosslinked single ion gel polymer electrolyte with superior performances for lithium metal batteries, Chemical Engineering Journal 382 (2020) 122935. https://doi.org/10.1016/J.CEJ.2019.122935.
- N.T.M. Balakrishnan, A. Das, J.D. Joyner, M.J. Jabeen Fatima, L.R. Raphael, A. Pullanchiyodan, P. Raghavan, Quest for high-performance gel polymer electrolyte by enhancing the miscibility of the bi-polymer blend for lithium-ion batteries: performance evaluation in extreme temperatures, Mater Today Chem 29 (2023) 101407. https://doi.org/10.1016/J.MTCHEM.2023.101407.
- L. Long, S. Wang, M. Xiao, Y. Meng, Polymer electrolytes for lithium polymer batteries, J Mater Chem A Mater 4 (2016) 10038–10069. https://doi.org/10.1039/C6TA02621D.
- K. Deng, Q. Zeng, D. Wang, Z. Liu, G. Wang, Z. Qiu, Y. Zhang, M. Xiao, Y. Meng, Nonflammable organic electrolytes for high-safety lithium-ion batteries, Energy Storage Mater 32 (2020) 425–447. https://doi.org/10.1016/J.ENSM.2020.07.018.
- K. Deng, Q. Zeng, D. Wang, Z. Liu, Z. Qiu, Y. Zhang, M. Xiao, Y. Meng, Single-ion conducting gel polymer electrolytes: design, preparation and application, J Mater Chem A Mater 8 (2020) 1557–1577. https://doi.org/10.1039/C9TA11178F.
- F. Larsson, P. Andersson, P. Blomqvist, A. Lorén, B.E. Mellander, Characteristics of lithium-ion batteries during fire tests, J Power Sources 271 (2014) 414–420. https://doi.org/10.1016/J.JPOWSOUR.2014.08.027.
- E. Lizundia, D. Kundu, Advances in Natural Biopolymer-Based Electrolytes and Separators for Battery Applications, Adv Funct Mater 31 (2021) 2005646. https://doi.org/10.1002/ADFM.202005646.
- X. Sun, W. Xu, X. Zhang, T. Lei, S.Y. Lee, Q. Wu, ZIF-67@Cellulose nanofiber hybrid membrane with controlled porosity for use as Li-ion battery separator, Journal of Energy Chemistry 52 (2021) 170–180. https://doi.org/10.1016/J.JECHEM.2020.04.057.
- W. Luo, S. Cheng, M. Wu, X. Zhang, D. Yang, X. Rui, A review of advanced separators for rechargeable batteries, J Power Sources 509 (2021) 230372. https://doi.org/10.1016/J.JPOWSOUR.2021.230372.
- R. Schmuch, R. Wagner, G. Hörpel, T. Placke, M. Winter, Performance and cost of materials for lithium-based rechargeable automotive batteries, Nature Energy 2018 3:4 3 (2018) 267–278. https://doi.org/10.1038/s41560-018-0107-2.
- J. Duan, X. Tang, H. Dai, Y. Yang, W. Wu, X. Wei, Y. Huang, Building Safe Lithium-Ion Batteries for Electric Vehicles: A Review, Electrochemical Energy Reviews 2019 3:1 3 (2019) 1–42. https://doi.org/10.1007/S41918-019-00060-4.
- K.S. Chen, I. Balla, N.S. Luu, M.C. Hersam, Emerging Opportunities for Two-Dimensional Materials in Lithium-Ion Batteries, ACS Energy Lett 2 (2017) 2026–2034. https://doi.org/10.1021/ACSENERGYLETT.7B00476/ASSET/IMAGES/MEDIUM/NZ-2017-00476B_0007.GIF.
- W. Ren, C. Ding, X. Fu, Y. Huang, Advanced gel polymer electrolytes for safe and durable lithium metal batteries: Challenges, strategies, and perspectives, Energy Storage Mater 34 (2021) 515–535. https://doi.org/10.1016/J.ENSM.2020.10.018.
- F. Baskoro, H.Q. Wong, H.J. Yen, Strategic Structural Design of a Gel Polymer Electrolyte toward a High Efficiency Lithium-Ion Battery, ACS Appl Energy Mater 2 (2019) 3937–3971. https://doi.org/10.1021/ACSAEM.9B00295/ASSET/IMAGES/MEDIUM/AE-2019-002958_0029.GIF.
- J. Pan, N. Wang, H.J. Fan, Gel Polymer Electrolytes Design for Na-Ion Batteries, Small Methods 6 (2022) 2201032. https://doi.org/10.1002/SMTD.202201032.
- X. He, Y. Ni, Y. Hou, Y. Lu, S. Jin, H. Li, Z. Yan, K. Zhang, J. Chen, Insights into the Ionic Conduction Mechanism of Quasi-Solid Polymer Electrolytes through Multispectral Characterization, Angewandte Chemie 133 (2021) 22854–22859. https://doi.org/10.1002/ANGE.202107648.
- J. Wang, S. Li, Q. Zhao, C. Song, Z. Xue, Structure Code for Advanced Polymer Electrolyte in Lithium-Ion Batteries, Adv Funct Mater 31 (2021) 2008208. https://doi.org/10.1002/ADFM.202008208.
- S. Kang, Z. Yang, C. Yang, S. Zhao, N. Wu, F. Liu, X. Chen, B. Shi, Co-blending based tribasic PEO-PS-PMMA gel polymer electrolyte for quasi-solid-state lithium metal batteries, Ionics (Kiel) 27 (2021) 2037–2043. https://doi.org/10.1007/S11581-021-03964-8/FIGURES/9.
- P. Xu, H. Chen, X. Zhou, H. Xiang, Gel polymer electrolyte based on PVDF-HFP matrix composited with rGO-PEG-NH2 for high-performance lithium ion battery, J Memb Sci 617 (2021) 118660. https://doi.org/10.1016/J.MEMSCI.2020.118660.
- X.H. Chan, M.H. Khanmirzaei, F.S. Omar, K. Ramesh, S. Ramesh, S. Ramesh, Enhanced efficiency in dye-sensitized solar cell based on zinc oxide-modified poly(ethylene oxide) gel electrolyte, Ionics (Kiel) 24 (2018) 1221–1226. https://doi.org/10.1007/S11581-017-2271-Y/TABLES/2.
- Y. Jiang, F. Li, Y. Mei, Y. Ding, H. Pang, P. Zhang, Gel polymer electrolyte based on hydrophilic–lipophilic TiO2-modified thermoplastic polyurethane for high-performance Li-ion batteries, J Mater Sci 56 (2021) 2474–2485. https://doi.org/10.1007/S10853-020-05360-5/FIGURES/7.
- J. Guo, H. Hou, J. Cheng, C. Wang, Q. Wang, H. Sun, X. Chen, Microporous bayberry-like nano-silica fillers enabling superior performance gel polymer electrolyte for lithium metal batteries, Journal of Materials Science: Materials in Electronics 32 (2021) 81–93. https://doi.org/10.1007/S10854-020-04645-4/FIGURES/7.
- G. Vijayakumar, N.R. Chandar, V. Tamilavan, Z. Said, R. Paramasivam, Physical and charge discharge behavior of facile PVDF-HFP nanocomposite microporous polymer electrolyte for lithium ion polymer batteries, Journal of Materials Science: Materials in Electronics 33 (2022) 8594–8606. https://doi.org/10.1007/S10854-021-06622-X/TABLES/4.
- S. Kataria, Y.L. Verma, H. Gupta, S.K. Singh, N. Srivastava, R. Dhar, R.K. Singh, Ionic liquid mediated nano-composite polymer gel electrolyte for rechargeable battery application, Https://Doi.Org/10.1080/25740881.2019.1708102 59 (2020) 952–958. https://doi.org/10.1080/25740881.2019.1708102.
- N.M. Khan, N.F. Mazuki, A.S. Samsudin, Contribution of Li+ Ions to a Gel Polymer Electrolyte Based on Polymethyl Methacrylate and Polylactic Acid Doped with Lithium Bis(oxalato) Borate, J Electron Mater 51 (2022) 745–760. https://doi.org/10.1007/S11664-021-09372-Y/METRICS.
- V.R. Jeedi, K.K. Ganta, I.S.R. Varma, M. Yalla, S. Narender Reddy, A.S. Chary, Alumina Nanofiller Functionality on Electrical and Ion Transport Properties of PEO-PVdF/KNO3/SN Nanocomposite Polymer Electrolytes, Results Chem 5 (2023) 100814. https://doi.org/10.1016/J.RECHEM.2023.100814.
- K.N. Kumar, M. Kang, K. Sivaiah, M. Ravi, Y.C. Ratnakaram, Enhanced electrical properties of polyethylene oxide (PEO) + polyvinylpyrrolidone (PVP):Li+ blended polymer electrolyte films with addition of Ag nanofiller, Ionics (Kiel) 22 (2016) 815–825. https://doi.org/10.1007/S11581-015-1599-4/TABLES/1.
- A. Saeed, S.O. Adewuyi, H.A.M. Ahmed, S.R. Alharbi, S.E. Al Garni, F. Abolaban, Electrical and Dielectric Properties of the Natural Calcite and Quartz, Silicon 14 (2022) 5265–5276. https://doi.org/10.1007/S12633-021-01318-7/METRICS.
- A. Saeed, M.S. Al-Buriahi, M.A.N. Razvi, N. Salah, F.E. Al-Hazmi, Electrical and dielectric properties of meridional and facial Alq3 nanorods powders, Journal of Materials Science: Materials in Electronics 32 (2021) 2075–2087. https://doi.org/10.1007/S10854-020-04974-4/METRICS.
- R. Kurniawan, I.M. Sutjahja, T. Winata, T.S. Herng, J. Ding, A. Rusydi, Y. Darma, E.R. Kurniawan, S. Nurfani, I.M. Muhammady, T. Sutjahja, A. Winata, Y. Rusydi, Polarization behavior of zinc oxide thin films studied by temperature dependent spectroscopic ellipsometry, Optical Materials Express, Vol. 7, Issue 11, Pp. 3902-3908 7 (2017) 3902–3908. https://doi.org/10.1364/OME.7.003902.
- A.A. Al-Muntaser, E. Banoqitah, M.A. Morsi, A.Y. Madkhli, J.A. Mohammed Abdulwahed, R. Alwafi, A.F. Al Naim, A. Saeed, Fabrication and characterizations of nanocomposite flexible films of ZnO and polyvinyl chloride/poly(N-vinyl carbazole) polymers for dielectric capacitors, Arabian Journal of Chemistry 16 (2023) 105171. https://doi.org/10.1016/J.ARABJC.2023.105171.
- S. Ramesh, C.W. Liew, Dielectric and FTIR studies on blending of [xPMMA–(1 − x)PVC] with LiTFSI, Measurement 46 (2013) 1650–1656. https://doi.org/10.1016/J.MEASUREMENT.2013.01.003.
- N.S. Alghunaim, Structural, thermal, dielectric spectroscopic and AC impedance properties of SiC nanoparticles doped PVK/PVC blend, Results Phys 9 (2018) 1136–1140. https://doi.org/10.1016/J.RINP.2018.04.023.
- W. Li, Z. Zhu, W. Shen, J. Tang, G. Yang, Z. Xu, A novel PVdF-based composite gel polymer electrolyte doped with ionomer modified graphene oxide, RSC Adv 6 (2016) 97338–97345. https://doi.org/10.1039/C6RA16618K.
- S. Borah, J.K. Sarmah, M. Deka, Understanding uptake kinetics and ion dynamics in microporous polymer gel electrolytes reinforced with SiO2 nanofibers, Materials Science and Engineering: B 273 (2021) 115419. https://doi.org/10.1016/J.MSEB.2021.115419.
- S. Borah, L. Saikia, A.K. Guha, M. Deka, SiO2 nanofiber reinforced P(VdF-HFP) based microporous polymer electrolytes for advanced energy storage applications, Colloids Surf A Physicochem Eng Asp 673 (2023) 131819. https://doi.org/10.1016/J.COLSURFA.2023.131819.
- S. Jamalpour, M. Ghahramani, S.R. Ghaffarian, M. Javanbakht, The effect of poly(hydroxyl ethyl methacrylate) on the performance of PVDF/P(MMA-co-HEMA) hybrid gel polymer electrolytes for lithium ion battery application, Polymer (Guildf) 195 (2020) 122427. https://doi.org/10.1016/J.POLYMER.2020.122427.
- Z. Chen, G.T. Kim, Z. Wang, D. Bresser, B. Qin, D. Geiger, U. Kaiser, X. Wang, Z.X. Shen, S. Passerini, 4-V flexible all-solid-state lithium polymer batteries, Nano Energy 64 (2019) 103986. https://doi.org/10.1016/J.NANOEN.2019.103986.
- T.G. Ritter, J.M. Gonçalves, S. Stoyanov, A. Ghorbani, T. Shokuhfar, R. Shahbazian-Yassar, AlTiMgLiO medium entropy oxide additive for PEO-based solid polymer electrolytes in lithium ion batteries, J Energy Storage 72 (2023) 108491. https://doi.org/10.1016/J.EST.2023.108491.
- S. Wang, L. Zhang, J. Li, Q. Zeng, X. Liu, P. Chen, W.Y. Lai, T. Zhao, L. Zhang, A nanowire-nanoparticle double composite polymer electrolyte for high performance ambient temperature solid-state lithium batteies, Electrochim Acta 320 (2019) 134560. https://doi.org/10.1016/J.ELECTACTA.2019.134560.
- M. Sasikumar, R.H. Krishna, M. Raja, H.A. Therese, N.T.M. Balakrishnan, P. Raghavan, P. Sivakumar, Titanium dioxide nano-ceramic filler in solid polymer electrolytes: Strategy towards suppressed dendrite formation and enhanced electrochemical performance for safe lithium ion batteries, J Alloys Compd 882 (2021) 160709. https://doi.org/10.1016/J.JALLCOM.2021.160709.
- T. Vorauer, J. Schöggl, S.G. Sanadhya, M. Poluektov, W.D. Widanage, L. Figiel, S. Schädler, B. Tordoff, B. Fuchsbichler, S. Koller, R. Brunner, Impact of solid-electrolyte interphase reformation on capacity loss in silicon-based lithium-ion batteries, Communications Materials 2023 4:1 4 (2023) 1–12. https://doi.org/10.1038/s43246-023-00368-1.
- S. Moon, H. Park, G. Yoon, M.H. Lee, K.Y. Park, K. Kang, Simple and Effective Gas-Phase Doping for Lithium Metal Protection in Lithium Metal Batteries, Chemistry of Materials 29 (2017) 9182–9191. https://doi.org/10.1021/ACS.CHEMMATER.7B03027/SUPPL_FILE/CM7B03027_SI_003.AVI.
- K. Khan, B. Fu, H. Xin, B.A. Beshiwork, M.B. Hanif, J. Wu, Z. Fang, J. Yang, T. Li, C. Chen, M. Motola, Z. Xu, M. Wu, Composite polymer electrolyte incorporating WO3 nanofillers with enhanced performance for dendrite-free solid-state lithium battery, Ceram Int 49 (2023) 4473–4481. https://doi.org/10.1016/J.CERAMINT.2022.09.333.
- J. Ni, L. Gao, Effect of copper doping on LiMnPO4 prepared via hydrothermal route, J Power Sources 196 (2011) 6498–6501. https://doi.org/10.1016/J.JPOWSOUR.2011.03.073.
No competing interests reported.