Solid Polymer Electrolyte Research Articles

In Situ Optical Observation of Lithium Dendrite Pattern in Solid Polymer Electrolytes.

Solid polymer electrolytes (SPEs) have been treated as a viable solution to build high-performance solid-state lithium metal batteries (SSLMBs) at the industrial level, bypassing the safety and energy density dilemmas experienced by today's lithium-ion battery technology. To promote a wider application of SPEs-based SSLMBs, the chemical and electrochemical characteristics of lithium metal (Li°) electrode in SPEs have to be clearly elucidated. In this work, the morphological evolution of Li° electrode in the SPEs-based SSLMBs is comprehensively investigated, via a customized electrochemical cell allowing optical microscopic analyses. The results demonstrate that differing from inorganic solid electrolytes, the elastic feature of SPEs eliminates the "memory effect" of the dendrite formation, in which the previously formed dendrites can be dissolved and the resulting space can be simultaneously occupied by electrolyte components, instead of leaving for a second-round growth of Li° dendrites. Furthermore, the largely increased electronic conductivities of the as-formed interphases between Li° electrode and SPEs are found to be responsible for the notoriously soft short-circuit behavior observed during cycling. These findings bring a fresh understanding of the formation and evolution of lithium dendrites in SPE-based cells, which are vital for improving the long-term stability of SSLMBs and other related high-energy battery systems.

Anion Modulation: Enabling Highly Conductive Stable Polymer Electrolytes for Solid‐State Li‐Metal Batteries

Solid polymer electrolytes (SPEs) are promising ionic conductors for developing high‐specific‐energy solid‐state lithium metal batteries. However, developing SPEs with both high ionic conductivity and interfacial compatibility remains a challenge. Here, we propose a design concept of an anion‐modulated polymer electrolyte (termed AMPE) for high‐voltage Li metal batteries. Specifically, we design the AMPE by incorporating high‐voltage‐resistant and high charge density units with an anion receptor unit. The high‐voltage‐resistant and high charge density segments contribute to achieving a decent voltage tolerance of the polymer chains and ensure sufficient carrier ions. The anion receptor, represented by a boron‐containing molecule, promotes the generation of free Li+ by dissociating anion‐cation pairs. More importantly, the strong interaction between the electron‐deficient B and the TFSI− in the matrix promotes the anion reduction to form a stable anion‐derived mosaic‐like solid electrolyte interphase on the Li‐metal anode. As a result, the AMPE exhibits a high Li+ conductivity of 3.80×10−4 S cm−1 and effectively suppresses lithium dendrites, enabling an all‐solid‐state Li|AMPE|LiCoO2 cell to achieve a cycle life of 700 cycles at an operating voltage of 4.40 V. This design concept would inspire efforts to develop high‐performance SPEs for high‐specific‐energy solid‐state lithium metal batteries.

Anion Modulation: Enabling Highly Conductive Stable Polymer Electrolytes for Solid-State Li-Metal Batteries.

Solid polymer electrolytes (SPEs) are promising ionic conductors for developing high-specific-energy solid-state lithium metal batteries. However, developing SPEs with both high ionic conductivity and interfacial compatibility remains a challenge. Here, we propose a design concept of an anion-modulated polymer electrolyte (termed AMPE) for high-voltage Li metal batteries. Specifically, we design the AMPE by incorporating high-voltage-resistant and high charge density units with an anion receptor unit. The high-voltage-resistant and high charge density segments contribute to achieving a decent voltage tolerance of the polymer chains and ensure sufficient carrier ions. The anion receptor, represented by a boron-containing molecule, promotes the generation of free Li+ by dissociating anion-cation pairs. More importantly, the strong interaction between the electron-deficient B and the TFSI- in the matrix promotes the anion reduction to form a stable anion-derived mosaic-like solid electrolyte interphase on the Li-metal anode. As a result, the AMPE exhibits a high Li+ conductivity of 3.80×10-4 S cm-1 and effectively suppresses lithium dendrites, enabling an all-solid-state Li|AMPE|LiCoO2 cell to achieve a cycle life of 700 cycles at an operating voltage of 4.40 V. This design concept would inspire efforts to develop high-performance SPEs for high-specific-energy solid-state lithium metal batteries.

Triple-Layered Noncombustible PEO-Based Solid Electrolyte for Highly Safe Lithium-Metal Batteries.

Lithium-metal batteries are currently recognized as promising next-generation technologies owing to their high energy density. Solid polymer electrolytes, particularly those based on polyethylene oxide (PEO), are lauded for their leakage resistance, safety, and flexible design. Despite the ongoing fire safety- and ionic conductivity-related concerns, a novel noncombustible solid polymer electrolytes with superior ionic conductivities are introduced here with additive decabromodiphenyl ethane and zeolite. To enhance the mechanical strength and ensure soft interactions at the electrode interface, a triple-layer structure with self-extinguishing properties and robust ionic conductivity is proposed. Notably, the softness at the electrode interface intensifies as the LiTFSI concentration increases; this higher concentration negatively impacts PEO crystallinity, enhancing the ionic conductivity owing to the presence of free Li+ and TFSI- ions. This novel electrolyte can achieve a conductivity of 1.5 mS cm-1 at 60°C, maintain anodic stability up to 4.8V, and exhibit flame retardancy. Furthermore, adding LiTFSI at 60% relative to PEO is shown to reduce LiF formation on the surface, enhancing anode stability. The [LiFePO4/triple-layered electrolyte/Li] lithium-metal batteries are capable of an initial capacity of 153 mAh g-1, sustained superior capacity retention of 87.9%, and high Coulombic efficiency (99.6%) over 1000 cycles at a 1C rate.

Naturally superionic polymer electrolyte of macromolecular lignin for all-solid-state sodium-ion batteries at room temperature

Solid polymer electrolytes (SPEs) that offer superior safety, mechanical strength and flexibility are crucial for advancing next-generation sodium-ion batteries (SIBs). Conventional SPEs often display temperature sensitivity, leading to relatively low ionic conductivity at room temperature (RT). Herein, lignin-based SPEs (LG-SPEs) are created by solvation and desolvation of lignin and sodium bis(fluorosulfonyl)imide (NaFSI). Theoretical calculations reveal that lignin (containing rich functional groups) and FSI− molecules facilitate the movement of Na-ions within the electrolyte by minimizing steric hindrance and offering migration sites. Consequently, LG-SPEs demonstrate an enhanced ionic conductivity of 3.4 × 10−4 S cm−1 at RT, with a Na-ion transfer number as high as 0.53. The assembled all-solid-state SIB comprising Na3V2(PO4)3/LG-SPE/NaTi2(PO4)3 exhibits excellent electrochemical performance at RT, achieving a specific capacity of 95 mA h g−1 and retaining 82% of its capacity after 200 cycles at 0.1 C. This work presents an environmentally friendly and straightforward methodology for developing high-performance SPEs at RT, while also opening up new avenues for the valorization of lignin.

Polymer electrolytes based on PEO and lithium tetraalkoxyborate salts with ionic liquid properties for lithium-based batteries

The development of lithium-ion batteries (LIBs) with improved safety features is crucial due to the inherent risks associated with liquid electrolytes, such as fires, explosions, and leakage. This study explores the potential of solid polymer electrolytes (SPEs) based on poly(ethylene oxide) (PEO) and lithium tetraalkoxyborate salts (LiTAB) with ionic liquid properties as a safer alternative. Ionic liquids (ILs) are examined for their high ionic conductivity, wide electrochemical window, and excellent thermal stability, despite their high synthesis costs and viscosity challenges. The study proposes the use of a novel LiTAB salt with an oligomeric star-shaped anion structure that reduces mobility, enhancing lithium ion transference numbers. This IL serves as both a lithium salt and an active plasticizer in PEO-based SPEs, offering potential for 3D printing applications. Experimental results demonstrate that these electrolytes exhibit favorable rheological properties, high ionic conductivities, and significant lithium ion transference numbers, addressing the key limitations of conventional PEO-based electrolytes. The findings suggest that incorporating these LiTAB salts in SPEs could significantly enhance the safety and performance of LIBs, particularly for applications in miniaturized consumer electronics and electronic implants.

Impact of tetracyanoethylene plasticizer on PEO based solid polymer electrolytes for improved ionic conductivity and solid-state lithium-ion battery performance

Poly(ethylene oxide) is a promising material for solid-state lithium batteries due to its safety, ease of processing, and compatibility with lithium. However, conventional linear PEO falls short of practical requirements due to its limited ionic conductivity, a consequence of the high crystallinity of its ethylene oxide chains. This crystallinity hinders the movement of lithium ions, limiting its performance in solid-state battery applications. In this study, we successfully prepared the plasticized solid polymer electrolytes (PSPEs) based on poly(ethylene oxide) (PEO)/tetracyanoethylene (TCE) complexed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and studied the effect of TCE on structural, mechanical, electrical and electrochemical properties of PSPEs. The addition of tetracyanoethylene effectively disrupts the crystallinity of the PEO matrix, as confirmed by X-ray diffraction analysis. The addition of TCE also enhanced the elongation-at-break of the PEO12-LiTFSI system, indicating improved flexibility. Consequently, the ionic conductivity of the SPEs increases with increasing tetracyanoethylene content, reaching a maximum of 1.14 × 10−4 S/cm at 25 °C for the electrolyte containing 30 wt% of tetracyanoethylene. Furthermore, the plasticized SPEs exhibit a wide electrochemical stability window, as determined by linear sweep voltammetry. Solid-state battery tests demonstrate a high initial discharge capacity of 143.5 mAhg−1 at 0.1C along with good cycling performance.

Robust polymer electrolytes with fast ion-transport nanochannels constructed by carbon dots for long lifespan Li metal batteries

As an anode material in energy storage systems, Li metal has exceptional merits, including high specific capacity, low density, and low redox potential. However, challenges such as lithium dendrites and unstable solid electrolyte interphase (SEI) hinder the practical application of lithium metal batteries (LMBs). Solid polymer electrolytes (SPEs), notably PVDF-HFP, are expected to overcome the above problems because of their mechanical merits and safe features, but their limited ion transportation behaviors result in insufficient ionic conductivity at room temperature. Herein, we invent an approach to prepare high performance electrolytes composed by porous PVDF-HFP and functionalized carbon dots (CDs). Such porous PVDF-HFP polymer membranes are created by a subtle phase inversion process, possessing a sponge-like structure, vertical lithium-ion transport channels and CDs decorated surfaces, thus able to uptake the liquid electrolyte (LE) to form gel polymer electrolytes (GPEs). The CDs fillers are produced in large scale with adjustable surface states, which can enhance Li salts disassociation to release free Li ions. As a result, the optimal conductivity of the as-prepared GPEs at room temperature is up to 8.7 mS cm−1 and the lithium transference number reaches 0.64. Our GPEs endow Li symmetric batteries with very stable SEI and long cycling life over 2200 h, and help realize high capacities and retention rates of the LMBs using LiFePO4(LFP) or LiCoO2(LCO) cathodes.

Enhancing Ionic Conductivity, Mechanical Stibility and Electrochemical Properties Simultaneously by integrating POSS-PEG13.3 Hybrid Nanoparticles into PEO-NaClO4 Solid Polymer Electrolytes

Enhancing Ionic Conductivity, Mechanical Stibility and Electrochemical Properties Simultaneously by integrating POSS-PEG13.3 Hybrid Nanoparticles into PEO-NaClO4 Solid Polymer Electrolytes

Tailored PEO/PEG-PPG Polymer Electrolyte for Solid-State Lithium-Ion Battery

Abstract Solid polymer electrolytes (SPEs) offer a promising avenue for advancing the performance and safety of all-solid-state batteries. In this study, we investigated the effects of blending poly(ethylene oxide) (PEO) with amorphous poly(propylene glycol) (PPG) or poly(ethylene glycol-ran-propylene glycol) (PEG-PPG) to engineer SPEs with enhanced electrochemical properties. By blending PEO with PEG-PPG or PPG, we effectively lowered the crystallinity of PEO, facilitating the diffusion of lithium ions through the SPE and broadening its operational temperature range. This optimization strategy enhanced ionic conductivity and significantly reduced the interfacial resistance between the electrolyte and electrode, thus improving electrochemical stability. The solid-state lithium/lithium iron phosphate (LiFePO4 or LFP) with PEO blended with 7% PEG-PPG showed excellent charge/discharge cycling stability, with maximal discharge capacities of 165 mAh g-1 and 162 mAh g-1 at a current rate of 0.2 C at 60 and 125°C, respectively. The PEG-PPG-based SPE outperformed the PPG polymer-based SPE in terms of better electrochemical performance and a wider temperature range due to its longer polymer chain. This combination offered improved ionic conductivity, interface stability, and electrolyte compatibility with electrodes, making it highly suitable for high-demand applications of lithium-ion batteries.

Tamarind gum based magnesium ion conducting polymer membrane for energy storage applications

A solid bio polymer electrolyte (SPE) based on tamarind gum (TG) and magnesium nitrate was synthesized by a solution casting technique. The amorphous behavior is observed by X-ray diffraction (XRD) analysis, and the degree of crystallinity is calculated from the XRD deconvolution spectra. The interaction between the polymer and the salt was confirmed by Fourier transform infrared (FTIR) analysis. Using FTIR deconvolution spectra, the percentage of free ions can be calculated. The glass transition temperature (Tg) was determined via differential scanning calorimetry (DSC). A higher ionic conductivity (σ) of 1.97 × 10−4 S/cm is observed for the sample with 1 g of tamarind gum and 0.5 g of magnesium nitrate (4 TMN). The conduction mechanism shows that sample 4 TMN obeys the quantum mechanical tunneling model (QMT) at low frequency. The prepared SPEs follow the Arrhenius behavior, and the minimum activation energy (Ea) of 0.207 eV is observed for sample 4 TMN. The lowest relaxation time (τ) was 3.46 × 10−7 s for 4-TMN according to the tangent spectra. The transference number of ions (tion) is calculated by Wagner’s polarization method. The electrochemical stability window observed by linear sweep voltammetry (LSV) is 2.25 V. The primary battery is fabricated by using sample 4TMN, and an open circuit voltage (OCV) of 2.01 V is observed.

Na3Zr2Si2PO12-Polymer Composite Electrolyte for Solid State Sodium Batteries.

The integration of the flexibility of organic polymer electrolyte and high ionic conductivity of the ceramic electrolyte is attempted in search of efficient and safer battery. Composite solid polymer electrolyte (CSPE) provides high ionic conductivity with a sustainable thin film of electrolyte having the synergistic effect of ionic liquid and active inorganic filler. The CSPE is synthesized by the solution cast technique using Na3Zr2Si2PO12 (NZSP) as ceramic and poly(vinylidene fluoride-hexafluoropropylene) with Salt-Ionic liquid as polymer electrolyte. X-ray diffraction (XRD) of CSPE includes amorphous nature due to the polymer part as well as crystalline peaks of ceramic NZSP, simultaneously. The prepared CSPE sample shows homogeneous and interconnected surface morphology is observed by Scanning electron microscopy (SEM) image. Thermogravimetric analysis (TGA) shows electrolyte is thermally stable up to 200 °C and differential scanning calorimetry (DSC) reveals decrease in degree of crystallinity due to NZSP addition in the CSPE. By complex impedance spectroscopy (CIS), room temperature ionic conductivity of the prepared CSPE is found ~1.03 mS/cm. The dielectric behaviour of the prepared electrolyte is also studied to investigate the ion dynamics within the sample. The cationic transference number is 0.53 and the electrochemical stability window (ESW) of the CSPE is 4.9 V which is suitable for sodium solid-state batteries applications.

Preparation, Characterization and Conductivity of SiO2 doped rGO-WO3 Composite for Battery Application

High-performance solid polymer electrolytes are regarded as one of the most promising materials to be used in the development of lithium ion batteries with improved extended life, increased recyclability and increased safety for electric vehicles and energy storage. In this work, a microwave-assisted hydrothermal technique was used to produce SiO2-doped rGO-WO3 composite, which possesses outstanding supercapacitor capabilities. This method is simple, low-cost method without using any other capping and reducing agents. The obtained SiO2 doped rGO-WO3 composite structural, morphology and components have been examined by XRD, FT-IR, FE-SEM, TEM, EDX, UV-visible techniques. It was found that the SiO2 doped rGO-WO3 composite well crystalline and the size range is about 20-30 nm. The SEM morphology results showed that the nanoparticles were stabilized by rGO, having cavity like structure and randomly distributed on the rGO-WO3 matrix. The solid state electrolyte revealed superior lithium ion transference number and cyclic stability. The SiO2 doped rGO-WO3 composite shows improved ionic conductivity of 2.74 × 10-5 S cm-1 at room temperature.

Design of Quasi‐Metal–Organic Frameworks for Solid Polymer Electrolytes Enabling an Ultra‐Stable Interface with Li Metal Anode

AbstractSolid polymer electrolytes (SPEs) are crucial in the development of lithium metal batteries. Recently, metal–organic frameworks (MOFs) with open metal sites (OMSs) have shown promise as solid fillers to improve the performance of SPEs. However, the number of OMS‐containing MOFs is quite limited, comprising less than 5% of the total MOFs. When considering yield, cost, and processability, the commonly used OMS‐containing MOFs are no more than 10 types, causing great limitations. Herein, we reported a simple and universal methodology that converted OMS‐free MOFs to OMS‐rich quasi‐MOFs for developing high‐performance SPEs, and explored the underlying mechanism. The “OMS‐polymer” and “OMS‐ion” interactions were investigated in detail to elucidate the role of quasi‐MOFs on battery performance. It was found that quasi‐MOFs, functioning as ion sieves, can effectively regulate ion migration, thus promoting uniform Li deposition and enabling an ultra‐stable interface. As a result, the Li symmetric cell stably ran over 3000 h at 0.3 mA cm−2, while the full cell retained 85 % of its initial capacity after 1500 cycles at 1.0 C. Finally, universal testing was performed using other MOFs, confirming the generalizability and effectiveness of our design concept.

Photoexcitation‐Enhanced High‐Ionic Conductivity in Polymer Electrolytes for Flexible, All‐Solid‐State Lithium‐Metal Batteries Operating at Room Temperature

Designing solid polymer electrolytes (SPEs) with high ionic conductivity for room‐temperature operation is essential for advancing flexible all‐solid‐state energy storage devices. Innovative strategies are urgently required to develop SPEs that are safe, stable, and high‐performing. In this work, we introduce photoexcitation‐modulated heterojunctions as catalytically active fillers within SPEs, guided by photocatalytic design principles, and employ natural bacterial cellulose to enhance the mechanical properties of the inorganic‐filled SPEs. In‐situ photothermal experiments and theoretical calculations reveal that the strong photogenerated electric field produced by trace heterojunctions within poly(ethylene oxide) electrolytes under photoexcitation significantly enhances lithium salt dissociation, increasing the concentration of mobile Li+. This results in a substantial increase in ionic conductivity, reaching 0.135 mS cm−1 at 25 °C, with a Li+ transference number as high as 0.46. The flexible all‐solid‐state lithium‐metal pouch cells exhibit an impressive discharge capacity of 178.8 mAh g−1 even after repeated bending and folding, and demonstrate exceptional long‐term cycling stability, retaining 86.7% of their initial capacity after 250 cycles at 1 C (25 °C). This research offers a novel approach to developing high‐performance flexible lithium‐metal batteries.

Review on polymer electrolytes for lithium‐sulfurized polyacrylonitrile batteries

AbstractLithium‐sulfur (Li‐S) batteries are deemed as the next generation of energy storage devices due to high theoretical specific capacity (1675 mAh g−1) and energy density (2600 Wh kg−1). However, the commercial application has always been constrained by lithium polysulfide (LiPSs) shuttling effects and still has a long way to go. Sulfurized polyacrylonitrile (SPAN) is a promising alternative candidate to replace traditional sulfur cathode and is conducive to eliminating LiPSs by realizing “solid‐solid” direct conversion in conventional carbonate electrolytes. However, an over 25% irreversible capacity loss is exhibited inevitably in the first discharge process, the inherent structure of SPAN and the related reaction mechanism remain unclear. In this review, the structure characteristics and electrochemical behaviors of SPAN are summarized for better interpreting current knowledge and favoring the design of high performance materials. In the past few decades, many problems in traditional Li‐S batteries have been solved by improving electrolytes. Polymer electrolytes (PEs) have been widely used due to structural designability, multi‐functionality, exceptional chemical stability, and excellent processability. Surprisingly, the relevant researches on PEs compatible with SPAN remains limited currently. Therefore, the recent modification strategies of gel polymer electrolytes and solid polymer electrolytes in Li‐SPAN batteries are introduced in terms of Li+ transfer and interface engineering, the design principles are concluded, the specific challenges encountered by polymer‐based electrolytes are summarized and the instructive directions for future research on PEs are demonstrated, facilitating the commercialization of Li‐SPAN batteries.

Enhancing the Filler Utilization of Composite Gel Electrolytes via In Situ Solution-Processable Method for Sustainable Sodium-Ion Batteries.

The composite gel electrolyte (CGE), which combines the advantages of inorganic solid-state electrolytes and solid polymer electrolytes, is regarded as the ultimate candidate for constructing batteries with high safety and superior electrode-electrolyte interface contact. However, the ubiquitous agglomeration of nanofillers results in low filler utilization, which seriously reduces structural uniformity and ion transport efficiency, thus restricting the development of consistent and durable batteries. Herein, a solution-processable method to in situ construct CGE with high filler utilization is introduced. The homogeneous metal-organic framework fillers contribute to uniform ionic and electronic filed distribution, realizing a stable electrode-electrolyte interface. Consequently, the CGE with high filler utilization achieves an ultra-long lifespan of 10000 cycles with a capacity retention of 80.2%. This work provides guidance for constructing high-performance CGEs in electrochemical energy-storage devices.

Solid‐State Revolution: Assessing the Potential of Solid Polymer Electrolytes in Lithium‐Ion Batteries

AbstractLithium‐ion batteries (LIBs) are crucial for achieving sustainable energy goals due to their high energy density and long cycle life. They dominate markets like consumer electronics, electric vehicles, and stationary energy storage systems. However, current LIBs use liquid electrolytes, which are toxic, flammable, and their liquid state does not resist dendrite growth, causing battery capacity decline and failure. Additionally, the limited availability of lithium and other metals makes liquid‐based LIBs less sustainable. On the other hand, solid polymer electrolytes (SPEs) offer a safer alternative as they are non‐volatile and can resist dendrite growth. However, ion transport in solids is much more restricted than in liquids, while imperfect solid‐solid interfaces contribute to interfacial resistance leading to lower ionic conductivity and increasing Ohmic losses or requiring battery operation at elevated temperatures. Chemical and mechanical degradation of these interfaces can also result in battery capacity fade, and poorer cyclic performance compared to liquid electrolytes. Understanding the ionic transport mechanisms in SPEs is critical for designing and optimizing the nanostructure of polymers and polymer/electrode interfaces to overcome these limitations. In this review, the fundamental mechanisms of ion transport in SPEs will first be explored. Various state‐of‐the‐art approaches for addressing the key challenges in SPEs and their solutions are then discussed. Furthermore, the current status of SPEs is analyzed to determine their potential for replacing liquid electrolytes in the future.

Solid-State Lithium Batteries with In Situ Polymerized Acrylate-Based Electrolytes Capable of Electrochemically Stable Operation at 100 °C.

Solid polymer electrolytes (SPEs) typically consist of salts with mobile anions that could cause instabilities and parasitic side reactions in solid-state lithium (Li) batteries. To address this challenge, single-Li-ion conducting (SLIC) SPEs, where anions of Li salts are covalently attached to the polymer backbone, have been utilized to reduce the number of mobile anions. This approach improves the cationic transference number but is accompanied by a loss of ionic conductivity. In this work, we investigate a synergetic approach of using both a polymerizable SLIC salt and a conventional Li salt in a polymer matrix by in situ polymerization of the poly(propylene glycol) acrylate (PPGA) monomer. The synthesized hybrid SPEs show a high ionic conductivity of up to ∼2 × 10-4 S cm-1 and a relatively high Li-ion transference number of ∼0.4. With a significantly reduced fraction of mobile anions in the combined salt SPE, in situ polymerized SPE cells with a LiFePO4 (LFP) cathode achieve a stable performance for over 100 cycles at temperatures as high as 100 °C, which is unattainable with conventional Li salts or electrolytes. Furthermore, solid-state nuclear magnetic resonance spectra provide additional insights into differences in Li nucleus environments and emphasize a reduction in activation energy for hybrid SPEs due to their more open structure. This study opens the path for the fabrication of high-performance solid polymer Li batteries capable of operating at high temperatures using commercial battery fabrication equipment, as in situ polymerized acrylate-based polymers provide drop-in compatibility with conventional battery production, ease of acrylate polymerization, and inexpensive, facile SPE chemistry. We expect that further tuning of the acrylate-based SPE composition may allow further increases in its conductivity without sacrificing its electrochemical stability or mechanical properties.

Formulating PEO-polycarbonate blends as solid polymer electrolytes by solvent-free extrusion

Liquid electrolytes are currently state-of-the-art for commercial Li-ion batteries. However, their use implicates inherent challenges, including safety concerns associated with flammability, limited thermal stability, and susceptibility to dendrite formation on the lithium metal anode, that can compromise the battery lifespan. Solid-state polymer electrolytes offer an alternative to conventional liquid electrolytes, aiming to mitigate safety, stability, and performance drawbacks. This study investigates the preparation and the comprehensive characterization of polyethylene oxide (PEO) and polycarbonate (PC) blends obtained through extrusion process. The process is solvent-free and easily scalable at the industrial level; it grants the efficient dispersion and mixing of PEO and PC. Blends at different ratios of PEO (Mw of 4 × 105 and 4 × 106 g mol˗1) and two types of PCs (namely, polyethylene and polypropylene carbonate) including lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) are prepared. Optimization and investigation of the relative effects between the application of different PCs and the variable ratios of PEO/PCs on the mechanical, morphologic and electrochemical properties of the final polymeric membranes is carried out for future applications of these systems, as efficient electrolytes in all-solid-state lithium batteries.