Polymer-based Electrolytes Research Articles

Polymer-Based Solid Electrolyte with Ultra Thermostability Exceeding 300 °C for High-Temperature Lithium-Ion Batteries in Oil Drilling Industries

Polymer-Based Solid Electrolyte with Ultra Thermostability Exceeding 300 °C for High-Temperature Lithium-Ion Batteries in Oil Drilling Industries

Polymer-Based Electrolyte for Lithium-Based High-Energy-Density and Safe Energy Storages Devices: Strategy and Mechanisms

Polymer-Based Electrolyte for Lithium-Based High-Energy-Density and Safe Energy Storages Devices: Strategy and Mechanisms

Poly(aniline)-multiwall carbon nanotube (PANI@MWCNT) composite as high-cost Pt free counter electrode for dye-sensitized solar cells

In this study, we synthesized a poly (aniline)-multiwall carbon nanotube (PANI@MWCNT) composite for use as a counter electrode (CE) in dye-sensitized solar cells. Moreover, FE-SEM and HR-TEM images of PANI@MWCNT revealed carbon nanotube/ropes embedded in the polymer matrix. An X-ray diffraction pattern confirmed the amorphous nature of the composite. Further, Electrochemical impedance spectroscopy studies indicated a charge transport resistance value (Rct) of 4.36 KΩ for PANI@MWCNT. CV studies demonstrated improved electrocatalytic performance and faster redox behavior in the PANI@MWCNT composite. BET analysis measured the pore size of the as-prepared composite to be 15–50 nm. Subsequently, the as-synthesized PANI, PANT@MWNCT, pristine MWCNT, and platinum were evaluated as CEs in DSSCs using a polyethylene oxide polymer-based liquid electrolyte and a TiO2 nanocrystalline photoanode. Among these CEs, the PANI@MWCNT CE exhibited an efficiency of 8.07 %, and the stability test indicated that the as-prepared composite CE retained 7.81 % efficiency after 15 days.

Polystyrene/Polyacrylonitrile/Polyindole based quasi solid electrolytes for DSSCs: Boosting both efficiency and stability

Recently, the utilization of quasi solid electrolytes has increased to overcome the stability and leakage issues caused by using liquid electrolytes in dye-sensitized solar cells. For this purpose, the novel different amounts of polystyrene/polyacrylonitrile/polyindole based quasi solid electrolytes were prepared and characterized via FTIR, GPC, TGA, DSC and electrochemical procedures. We aimed to develop conductive polymer-based solid electrolytes to be used in DSSCs to improve both solar cell conversion efficiency and stability. The conversion efficiency value of the solar cell using semi-solid electrolyte (PC4) boosted (9.91%) compared to the one using liquid electrolyte (9.74%). Additionally, the solar cells’ stabilities prepared with quasi solid electrolytes are two times higher than solar cells including liquid electrolytes. Therefore, in this study, the potentials of using conductive polymer-based quasi solid electrolytes in DSSCs were investigated and promising results were acquired for future applications.

Stable Efficient Solid-State Supercapacitors and Dye-Sensitized Solar Cells Using Ionic Liquid-Doped Solid Biopolymer Electrolyte.

As synthetic and nonbiodegradable compounds are becoming a great challenge for the environment, developing polymer electrolytes using naturally occurring biodegradable polymers has drawn considerable research interest to replace traditional aqueous electrolytes and synthetic polymer-based polymer electrolytes. This study shows the development of a highly conducting ionic liquid (1-hexyl-3-methylimidazolium iodide)-doped corn starch-based polymer electrolyte. A simple solution cast method is used to prepare biopolymer-based polymer electrolytes and characterized using different electrical, structural, and photoelectrochemical studies. Prepared polymer electrolytes are optimized based on ionic conductivity, which shows an ionic conductivity as high as 1.90 × 10-3 S/cm. Fourier transform infrared spectroscopy (FTIR) confirms the complexation and composite nature, while X-ray diffraction (XRD) and polarized optical microscopy (POM) affirm the reduction of crystallinity in biopolymer electrolytes after doping with ionic liquid (IL). Thermal and photoelectrochemical studies further affirm that synthesized material is well stable above 200 °C and shows a wide electrochemical window of 3.91 V. The ionic transference number measurement (t ion) confirms the predominance of ionic charge carriers in the present system. An electric double-layer capacitor (EDLC) and a dye-sensitized solar cell (DSSC) were fabricated by using the highest conducting corn starch polymer electrolyte. The fabricated EDLC and DSSC delivered an average specific capacitance of 130 F/g and an efficiency of 1.73% in one sun condition, respectively.

Electrochemical-mechanical coupled interfacial degradation model of Ternary polymer composite cathodes in all-solid-state batteries

Despite significant attention focused on the composite cathode composed of active particles, which is considered to increase the interfacial areas and satisfy high areal load, suffers from interfacial issues. In this article, we formulate an electrochemical-mechanical model of LiNixMnyCozO2 (NMC) composite cathode coupling the relations between interfacial degradation, charge transformation, diffusion transport, and mechanical deformation under cyclic loads. Based on the transition state theory, we regard the interfacial degradation as an energy barrier dependent on the interfacial debonding state. Physical mismatch due to chemical expansion results in interfacial current distinction, anisotropic Li diffusion and excessive local stress. Compared to single-crystal NMC particles, the effect of interfacial separation and internal cracks triggers an extremely nonuniformity of Li distribution within random orientation polycrystalline-type particles. The external pressure in the range of operation can cause mechanical deformation to fill in the interface vacancies, which effectively alleviates the rapid growth of damage and provides a better cyclic performance. Moreover, soft polymer-based solid electrolytes take advantage of their flexible property to deal with solid-solid contact, providing considerable maintenance of interface stability. This present framework reveals the failure mechanism with electrochemical-mechanical coupled relations for composite cathode materials and broadens the design guidance toward improving interfacial integrity.

Conducting Composite Polymer-Based Solid-State Electrolyte with High Ion Conductivity via Amorphous Condensed Structure and Multiple Li+ Transport Channels.

Traditional PEOelectrolyte has high crystallinity which hinders the transmission of Li+, resulting in poor ion conductivity and complicated processing technology. Herein, a polymer electrolyte (p-electrolyte) with a wide electrochemical window and high ionic conductivity is designed, which possesses an amorphous condensed structure. The amorphous structure provides fast transport channels for Li+, so the p-electrolyte possesses an electrochemical window of 4.2V, and high ionic conductivity of 1.58 × 10-5Scm-1 at room temperature, which is 1-2 orders of magnitude higher than that of traditional PEO electrolyte. By using the designed polymer electrolyte as the foundation, an in situ curable composite polymer electrolyte (CPE-L) with multiple Li+ transport channels is elaborately constructed. The Cu-BTC MOF stores abundant Li+, which is introduced into the p-electrolyte. The rich unsaturated Cu2+ coordination sites of Cu-BTC can anchor TFSI- to release Li+, and the pore structure of Cu-BTC MOF cooperates with LLZTO nanoparticles to provide multiple fast transport channel for Li+, resulting in remarkable ionic conductivity (1.02 × 10-3Scm-1) and Li+ transference number (0.58). The Li||CPE-L||Li symmetric battery cycles stably for more than 700h at 0.1mAcm-2, while the specific capacity of full battery is ≈153mAhg-1 (RT, 0.2C).

Synergistic Enhancement of Mechanical and Electrochemical Properties in Grafted Polymer/Oxide Hybrid Electrolytes.

Lithium metal batteries operated with high voltage cathodes are predestined for the realization of high energy storage systems, where solid polymer electrolytes offer a possibility to improve battery safety. Al2O3_PCL is introduced as promising hybrid electrolyte made from polycaprolactone (PCL) and Al2O3 nanoparticles that can be prepared in a one-pot synthesis as a random mixture of linear PCL and PCL-grafted Al2O3. Upon grafting, synergistic effects of mechanical stability and ionic conductivity are achieved. Due to the mechanical stability, manufacture of PCL-based membranes with a thickness of 50µm is feasible, yielding an ionic conductivity of 5·10-5S cm-1 at 60°C. The membrane exhibits an impressive performance of Li deposition in symmetric Li||Li cells, operating for 1200h at a constant and low overvoltage of 54mV and a current density of 0.2mA cm-2. NMC622|Al2O3_PCL|Li cells are cycled at rates of up to 1 C, achieving 140 cycles at >80% state of health. The straightforward synthesis and opportunity of upscaling as well as solvent-free polymerization render the Al2O3_PCL hybrid material as rather safe, potentially sustainable and affordable alternative to conventional polymer-based electrolytes.

Solid-state rigid polymer composite electrolytes with in-situ formed nano-crystalline lithium ion pathways for lithium-metal batteries

Polymer-based solid-state electrolytes with excellent processability and flexibility are ideal candidates for commercialisation in lithium-metal batteries. However, the current polymer-based solid-state electrolytes still have many problems such as low ionic conductivity, limited Li+ transport number and high interfacial resistance with electrodes. To address the above challenges, a solid-state rigid polymer composite electrolyte with high ionic conductivity (2.8 mS cm−1) has been prepared based on the rigid polymer poly(2, 2′-disulfonyl-4, 4′-benzidine terephthalamide) (PBDT). Locally aligned PBDT-EMImN(CN)2 grains are interspersed with in-situ formed interconnected LiFSI to form the structure of the polymer composite electrolyte. The formation of defective LiFSI nanocrystals at grain boundaries inside the polymer electrolyte acts as additional conductive networks providing fast Li+ transportation (tLi+ = 0.59). The flexible region in the electrolyte gives excellent interfacial impedance (32.5 Ω cm2) with Li-metal electrode. The Li||Li batteries can be stably cycled for over 1000 cycles at 1 mA cm−2 (25 °C). The assembled Li||LiFePO4 batteries exhibit excellent cycling and multiplication performance over a wide operating temperature (from −20 to 60 °C). Moreover, this electrolyte material exhibits compatibility with high-voltage cathode LiNi0.6Mn0.2Co0.2O2 batteries. This electrolyte and design strategy is expected to inspire the realization of all-weather practical solid-state lithium-metal batteries.

A New Class of Lithium Conductive Polymers for Solid State Lithium Metal Batteries at Room Temperature

Lithium-ion batteries (LIBs), among various secondary battery technologies, have received a significant amount of attention in the last decades, becoming the most successful commercial batteries. Extensively used in portable electronics, electric vehicles, and energy storage stations, LIBs meet many challenges, such as safety problems, low energy densities and so on, which drives much research toward developing the next generation of battery technology. Solid-state batteries emerge as one of the most potential alternatives for mainstream LIBs. Polymer-based solid-state electrolytes (SSEs) have been widely studied due to their softness and flexibility, relieving interface problems between electrodes and separators, especially compared with inorganic solid electrolytes. However, their limitations, such as limited Li+ conductivity or narrow electrochemical windows (< 4 V), restrict their potential applications. In this presentation, a new type of polymer (PG23), developed by Piersica Inc. (www.piersica.com) were applied as excellent binder to organic electrolyte based LIBs, and also to all solid state LIBs. Solid state electrolyte (SSEs) based on the polymer PG23 exhibits impressive conductivity (0.1 mS/cm) at room temperature and extremely high oxidized stability (approx. 4.9 V). When the SSEs was applied to both solid cathode (NMC622 as active material) and SSEs, combined with Li metal as anode, the LIBs demonstrated excellent capacity and cycling stability operating at room temperature. This polymer from Piersica Inc. exhibits considerable promise for the development and enhancement of solid-state batteries.

Improving Zn2+ migration via designing multiple zincophilic polymer electrolyte for advanced aqueous zinc ion batteries

Aqueous zinc ion batteries (AZIBs)-based on Zn metal anode face serious issues of hydrogen evolution, corrosion, and zinc dendrite growth, limiting their practical applications. Polymer-based electrolytes can effectively inhibit the above issue, but usually bring additional interfacial resistance, resulting in slow reaction kinetics. Herein, we report a poly(4-acryloylmorpholine) electrolyte with multiple zincophilic primitives for fast zinc ion transport at bulk and interface of Zn metal anode (zinc ion transfer number of 0.77) via a facile one-pot polymerization. The special electrolyte structure with multiple zincophilic primitives can adhere tightly to the Zn metal anode and induce uniform Zn deposition, resulting in low interface resistance and enhanced cycling life of batteries. Therefore, the symmetric Zn||Zn batteries assembled based on the designed and synthesized polymer electrolyte can be stably cycled for 1400 with low overpotential (∼220 mV) at 0.5 mA cm−2 with a capacity of 0.5 mAh cm−2, and the corresponding V2O5||Zn full batteries exhibit attractive reversibility, rate performance, and cycling stability. The electrolyte engineering in this work paves a new path for the construction of polymer-based electrolytes for safe and stable AZIBs.

Injection-molded PEO/MXene nanocomposite for polymer-based solid-state electrolyte

The solid-state electrolyte constitutes a major component in an all-solid-state lithium-ion battery. It plays a critical role in determining the lifetime and performance of the battery. Among the materials used in polymer-based solid-state electrolytes, poly (ethylene oxide) (PEO) is widely studied due to its high ionic conductivity and excellent solubility in lithium salts. However, the high crystallinity of PEO still remains a challenge to overcome, leading to poor ionic conductivity compared to other solid-state electrolytes. Herein, we fabricated MXene-embedded PEO nanocomposites for solid-state electrolytes using the injection molding process. MXenes were synthesized by using HF and MILD etching methods. The particle characteristics were evaluated through morphological, elemental, and structural analyses. In addition, the thermal, mechanical, and rheological properties of the solid electrolyte were examined. The solid-state electrolyte was injection-molded, and the flow and deformation of the molten polymer were modeled numerically. Also, the performance of the lithium-ion battery was simulated. The addition of MXene resulted in an approximately 80 times improvement of ionic conductivity, i.e., 1.0 ×10−4 S/cm.

Controlled Migration of Lithium Cations by Diamine Bridges in Water-Processable Polymer-Based Solid-State Electrolyte Memory Layers for Organic Synaptic Transistors.

Synaptic transistors require sufficient retention (memory) performances of current signals to exactly mimic biological synapses. Ion migration has been proposed to achieve high retention characteristics but less attention has been paid to polymer-based solid-state electrolytes (SSEs) for organic synaptic transistors (OSTRs). Here, OSTRs with water-processable polymer-based SSEs, featuring ion migration-controllable molecular bridges, which are prepared by reactions of poly(4-styrenesulfonic acid) (PSSA), diethylenetriamine (DETA), and lithium hydroxide (LiOH) are demonstrated. The ion conductivity of PSSA:LiOH:DETA (1:0.4:X, PLiD) films is remarkably changed by the molar ratio (X) of DETA, which is attributed to the extended distances between the PSSA chains by the DETA bridges. The devices with the PLiD layers deliver noticeably changed hysteresis reaching an optimum at X = 0.2, leading to the longest retention of current signals upon single/double pulses. The long-term potentiation test confirms that the present OSTRs can gradually build up the postsynaptic current by gate pulses of -2V, while the long-term depression can be adjusted by varying the depression gate pulses (≈0.2-1.2V). The artificial neural network simulations disclose that the present OSTRs with the ion migration-controlled PLiD layers can perform synaptic processes with an accuracy of ≈96%.

Localized high concentration polymer electrolyte enabling room temperature solid-state lithium metal batteries with stable LiF-rich interphases

Polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) based polymer electrolyte shows mechanical flexibility, soft and intimidate physical contact and good electrochemical stability, however, low ionic conductivity at room temperature and unstable interphases against Li metal hinder its application. In this article, we propose a universal strategy to prepare localized high concentration polymer electrolytes (LHCPE) in which high concentration lithium salt (LiTFSI) dissolved in tiny residual solvent (DMF) and the PVDF-HFP serves as solid dilution. The LHCPE regulates the solvation structure of lithium ions with anions instead of DMF solvent, allowing more anions to coordinate with Li+ and forming amount contact ion pairs (CIPs) and aggregates (AGGs). As a result, high ionic conductivity (5.9 × 10−4 S cm−1) and low activation energy (0.10 eV) achieved. The LHCPE also induces the decomposition of anions-derived LiF-rich interphases, that is ionic conducive and mechanical robust, thereby greatly improving the charge transfer kinetics and stability towards Li metal anodes. Consequently, at 0.5 mA cm−2 and 0.25 mAh cm−2, stable and long-term cycling over 2000 h obtained under room temperature in Li//Li symmetric cells achieved. The full solid-state LFP//LHCPE//Li cells further exhibit excellent capacity retention of 82.83 % even after 1200 cycles at room temperature and a high rate of 8 C (1C=170 mA·g−1). Our work shed light on the design of high-performance polymer-based composite electrolytes by manipulating the Li solvation structure.

Boosting lithium-ion conductivity of polymer electrolyte by selective introduction of covalent organic frameworks for safe lithium metal batteries

The demand for high-energy-density batteries has prompted exploration into advanced materials for enhancing the safety and performance of lithium metal batteries (LMBs). This study introduces a novel approach, incorporating two-dimensional (2D) pyrazine and imine-linked covalent organic frameworks (COFs) into a polyethylene oxide (PEO)-based solid electrolyte matrix. The synthesized COFs act as multifunctional additives, improving mechanical strength, ionic conductivity (reaching 1.86 ×10−3 S/cm at room temperature), electrochemical window (oxidation resistance up to 5 V vs. Li/Li+), and thermal stability (up to 400 °C). The unique electron-rich and polar functionalities of pyrazine and imine linkages facilitate strong interactions with lithium ions (Li+), resulting in a flexible composite solid electrolyte that mitigates dendrite formation and interface instability. Electrochemical performance of LMBs with LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode further confirm the enhanced Li+ conductivity, prolonged cycling stability, and a stable solid electrolyte interface, showcasing the potential of COFs in improving LMB performance. Overall, this study highlights the promising role of pyrazine and imine-linked COFs as effective additives for polymer-based solid electrolytes and their potential for developing safer and more efficient LMBs in the future.

Polymer-based electrolytes for high-voltage solid-state lithium batteries

Increasing the charging cut-off voltage of lithium batteries is a feasible method to enhance the energy density. However, when batteries operate at high voltages (&gt; 4.3 V), the degradation of liquid organic carbonate electrolyte is accelerated and may cause safety hazards. Polymer-based electrolytes with inherently high safety and good electrochemical stability can prevent the electrolyte degradation in high-voltage solid-state lithium batteries. This paper provides a comprehensive and in-depth review of the design strategies, recent developments, and scientific challenges associated with polymer-based electrolytes for high-voltage applications. Emphases are placed on the interfacial compatibility between electrolytes and cathodes, such as mechanical contacts and interface chemical stability, which are critical to the lifespan of high-voltage lithium batteries. Moreover, guidelines for the future development of high-voltage solid-state lithium batteries are also discussed.

Design a polymer-based composite electrolyte with high ionic conductivity for high-performance lithium-metal batteries

Constructing a stable and robust solid polymer electrolyte (SPE) is crucial for achieving dendrite-free lithium-metal anodes and high-performance lithium batteries. However, realizing the integrity of solid electrolytes with high ion conductivity during long-life cycling under high current density remains a significant challenge. In this study, we propose a multifunctional SPE with a polyvinylidene fluoride (PVDF)/co-polyphenol coordination polymer (EACo2) hybrid composite to improve the durability of Li metal anode during repeat plating/stripping cycles by using a facile solution-casting method. The PVDF as a substrate with high mechanical strength and improved lithiophilicity exhibits high ionic conduction and excellent dendrite inhibition ability; meanwhile, the EACo2 fillers with a high density of Lewis-acidic sites contribute to the dissociation of lithium salts and decrystallization of the PVDF, resulting in a high Li-ion transference number and ion conductivity (2.66 × 10−3 S cm−1 at 30 ℃). The symmetrical cells with PVDF/EACo2 SPE can stabilize cycling over 1200 hours at a deposition capacity of 0.1 mAh cm−2. Moreover, the assembled full cells Li|LiFePO4 demonstrate long-term stability (1000 cycles at 1 C) with impressive capacity retention of 75 %, offering a promising approach towards high-performance lithium metal batteries.

Exploring MXene-MOF composite for supercapacitor application

In the present work, a composite (Ti3C2Tx/Ni-MOF) of titanium carbide MXene (Ti3C2Tx) and nickel-based metal-organic framework (Ni–NH2BDC MOF) has been studied for supercapacitor application. The idea behind using the mentioned composite lies in the fact that composite formation helped prevent the restacking and oxidation of MXene sheets, thus inducing stability in the overall system. The improvement in the stability of these Ti3C2Tx nanosheets intercalated with MOFs could be observed in their electrochemical properties in the form of significant enhancement of capacitance and power density before and after composite formation. The symmetric supercapacitor device was assembled using two electrodes of similar weight with polymer-based gel electrolyte (Polyvinyl alcohol in 1 M H2SO4). The device provided the potential window of 0–2.0 V with a specific capacitance of 139.4 F/g at a current density of 1 A/g with energy density and power density of 19.4 Wh/kg and 331.8 W/kg, respectively. Capacitive retention of 95 % was observed even after 5000 charging-discharging cycles. The observed response confirms that the synthesised composite can be a suitable electrode material for future energy storage applications.

Effect of CdS on the Electrical Conductivity of Polyvinyl Alcohol (PVA) and Potassium Iodide (KI) thin films

In the past two decades, solid polymer electrolytes (SPEs) have attracted attention as a platform for electrochemical devices. Here polymer-based electrolytes have the advantage that they can be grown in a thin film, plus they are leak-proof. In the present work, we have used PVA:KI as the host polymer–salt complex with a composition of 85:15. Further, this PVA:KI complex dispersed with different wt% of CdS. Standard solution cast techniques have been used for thin film preparation. All prepared samples are characterized to study conductivity and structural changes. A maximum ionic conductivity of 2.47 X 10-7 S/cm was observed for 9wt% of CdS. Also, the band gap of these films was calculated and found to be between 2.4 to 2.9 eV. Also, the concentration and mobility of charge carriers were calculated to explain the change in conductivity pattern. This calculation was performed with the Schutt &amp; Gerdes model. It is observed that the conductivity pattern mainly follows the concentration of charge carriers. DOI: https://doi.org/10.52783/pst.370

A locally solvent-tethered polymer electrolyte for long-life lithium metal batteries

Solid polymer electrolytes exhibit enhanced Li+ conductivity when plasticized with highly dielectric solvents such as N,N-dimethylformamide (DMF). However, the application of DMF-containing electrolytes in solid-state batteries is hindered by poor cycle life caused by continuous DMF degradation at the anode surface and the resulting unstable solid-electrolyte interphase. Here we report a composite polymer electrolyte with a rationally designed Hofmann-DMF coordination complex to address this issue. DMF is engineered on Hofmann frameworks as tethered ligands to construct a locally DMF-rich interface which promotes Li+ conduction through a ligand-assisted transport mechanism. A high ionic conductivity of 6.5 × 10−4 S cm−1 is achieved at room temperature. We demonstrate that the composite electrolyte effectively reduces the free shuttling and subsequent decomposition of DMF. The locally solvent-tethered electrolyte cycles stably for over 6000 h at 0.1 mA cm−2 in Li | |Li symmetric cell. When paired with sulfurized polyacrylonitrile cathodes, the full cell exhibits a prolonged cycle life of 1000 cycles at 1 C. This work will facilitate the development of practical polymer-based electrolytes with high ionic conductivity and long cycle life.