Solid Plasticizer Research Articles

Isolation and characterization of biomass waste based bioplasticizer from Eucalyptus leaf: A suitability analysis of biofiller for polymeric composites

Plasticizers improve polymeric materials' properties and processability as additives. Currently, a variety of liquid synthetic plasticizers derived from fossil fuels are available. The environmental unsuitability of these materials could potentially lead to adverse effects on the environment. When we compare solid and liquid plasticizers, we find an infinite variety of liquid plasticizers. As a result, our work focuses on the extraction of plasticizer from plant sources. Accordingly, the plasticizer is extracted from eucalyptus leaves via solvent purification and surface catalysis. Research was conducted utilizing X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Ultraviolet (UV) visible spectroscopy to determine the characteristics of plasticizer. The scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis are used to analyze the surface morphology of the isolated plasticizer. The plasticizer's UV examination reveals active absorption at 375.21 nm. The plasticizer was determined to have a lower density of 0.941 g/cm3. The plasticizer that was extracted had a low solubility in water and organic solvents while possessing an estimated molecular weight of 340. The glass transition temperature of plasticizer was also examined using differential scanning electron microscopy analysis and found to be 64.17 °C. The crystallinity index and size were found to be 34.08 % and 28.57 nm, respectively. The characteristic features obtained were well-suited for use as filler in polymer composite materials.

Understanding the Interaction of Thermal, Rheological, and Mechanical Parameters Critical for the Processability of Polyvinyl Alcohol-Based Systems during Hot Melt Extrusion.

Hot melt extrusion (HME) is a common manufacturing process used in the pharmaceutical industry to improve the solubility of poorly soluble active pharmaceutical ingredients (API). The goal is to create an amorphous solid dispersion (ASD) where the amorphous form of the API is stabilized within a polymer matrix. Traditionally, the development of pharmaceutically approved polymers has focused on requirements such as thermal properties, solubility, drug-polymer interactions, and biocompatibility. The mechanical properties of the material have often been neglected in the design of new polymers. However, new downstream methods require more flexible polymers or suitable plasticizer polymer combinations. In this study, two grades of the polymer polyvinyl alcohol (PVA), which is already established for HME, are investigated in terms of their mechanical, rheological, and thermal properties. The mechanical properties of the extruded filaments were tested by the three-point bending test. The rheological behavior was analyzed by oscillating plate measurements. Thermal analysis was performed by differential scanning calorimetry (DSC). In addition, the solid and liquid plasticizers mannitol, sorbitol, triacetin, triethyl citrate, polyethylene glycol, and glycerol were evaluated for use with PVA and their impact on the polymer properties was elaborated. Finally, the effects of the plasticizers are compared to each other, and the correlations are analyzed statistically using principal component analysis (PCA). Thereby, a clear ranking of the plasticizer effects was established, and a deeper understanding of the polymer-plasticizer interactions was created.

A Fully Amorphous, Dynamic Cross-Linked Polymer Electrolyte for Lithium-Sulfur Batteries Operating at Subzero-Temperatures.

Solid-state lithium-sulfur batteries have shown prospects as safe, high-energy electrochemical storage technology for powering regional electrified transportation. Owing to limited ion mobility in crystalline polymer electrolytes, the battery is incapable of operating at subzero temperature. Addition of liquid plasticizer into the polymer electrolyte improves the Li-ion conductivity yet sacrifices the mechanical strength and interfacial stability with both electrodes. In this work, we showed that by introducing a spherical hyperbranched solid polymer plasticizer into a Li+ -conductive linear polymer matrix, an integrated dynamic cross-linked polymer network was built to maintain fully amorphous in a wide temperature range down to subzero. A quasi-solid polymer electrolyte with a solid mass content >90 % was prepared from the cross-linked polymer network, and demonstrated fast Li+ conduction at a low temperature, high mechanical strength, and stable interfacial chemistry. As a result, solid-state lithium-sulfur batteries employing the new electrolyte delivered high reversible capacity and long cycle life at 25 °C, 0 °C and -10 °C to serve energy storage at complex environmental conditions.

A Fully Amorphous, Dynamic Cross‐Linked Polymer Electrolyte for Lithium‐Sulfur Batteries Operating at Subzero‐Temperatures

AbstractSolid‐state lithium‐sulfur batteries have shown prospects as safe, high‐energy electrochemical storage technology for powering regional electrified transportation. Owing to limited ion mobility in crystalline polymer electrolytes, the battery is incapable of operating at subzero temperature. Addition of liquid plasticizer into the polymer electrolyte improves the Li‐ion conductivity yet sacrifices the mechanical strength and interfacial stability with both electrodes. In this work, we showed that by introducing a spherical hyperbranched solid polymer plasticizer into a Li+‐conductive linear polymer matrix, an integrated dynamic cross‐linked polymer network was built to maintain fully amorphous in a wide temperature range down to subzero. A quasi‐solid polymer electrolyte with a solid mass content >90 % was prepared from the cross‐linked polymer network, and demonstrated fast Li+ conduction at a low temperature, high mechanical strength, and stable interfacial chemistry. As a result, solid‐state lithium‐sulfur batteries employing the new electrolyte delivered high reversible capacity and long cycle life at 25 °C, 0 °C and −10 °C to serve energy storage at complex environmental conditions.

Developing flexible and safety-reinforced 3D polymer electrolytes based on polyethylene oxide for solid-state lithium metal batteries

Poly (ethylene oxide) (PEO) is a potential material for solid-state lithium batteries. However, the present polymer electrolyte is hampered by its low ionic conductivity at room temperature and poor mechanical properties, which are significant barriers to its practical application. Herein, we designed a high-performance composite solid electrolyte (PLSP) by incorporating PEO, LiTFSI, and the solid plasticizer butanedinitrile into a 3D polyethylene terephthalate (PET) nonwoven framework with excellent mechanical properties. The PLSP achieved an impressive ionic conductivity of 5.45 × 10−4S cm−1, nearly 100 times higher than the original PEO electrolyte (6.1 × 10−6 S cm−1) at room temperature. Additionally, the optimized composite electrolyte exhibited an extended electrochemical window of up to 5.2 V vs. Li+/Li and a remarkable tensile strength exceeding 8.55 MPa. The stability of the lithium symmetrical battery's charge and discharge voltage platform after 400 h of cycling indicated favorable interfacial compatibility between the PLSP and lithium metal. Furthermore, the assembled Li/PLSP/LFP configuration displayed a discharge specific capacity of 131.4 mA h g−1 and a capacity retention of 93.8 % after 100 cycles at 1C at room temperature, highlighting the promising potential of the composite electrolyte for solid-state lithium batteries.

Functionality of 1‐Butyl‐2,3‐Dimethylimidazolium Bromide (BMI‐Br) as a Solid Plasticizer in PEO‐Based Polymer Electrolyte for Highly Reliable Lithium Metal Batteries (Adv. Energy Mater. 47/2023)

Functionality of 1‐Butyl‐2,3‐Dimethylimidazolium Bromide (BMI‐Br) as a Solid Plasticizer in PEO‐Based Polymer Electrolyte for Highly Reliable Lithium Metal Batteries (Adv. Energy Mater. 47/2023)

Functionality of 1‐Butyl‐2,3‐Dimethylimidazolium Bromide (BMI‐Br) as a Solid Plasticizer in PEO‐Based Polymer Electrolyte for Highly Reliable Lithium Metal Batteries

AbstractTo address the challenges associated with solid polymer electrolytes, flame‐retardant organic ionic plastic crystals (OIPCs) have been utilized as a solid plasticizer in composite polymer electrolytes (CPEs). In this study, 1‐butyl‐2,3‐dimethylimidazolium bromide (BMI‐Br) is used as an OIPC material. BMI‐Br and LiTFSI are initially mixed in an acetonitrile (ACN) organic solvent for a certain time. Anion exchange takes place in this mixing, replacing the Br− in BMI‐Br with TFSI−. As a result, BMI‐TFSI and Li‐Br are formed. Here, BMI‐TFSI acts as an ionic liquid, while Li‐Br serves as a salt. The 10% BMI‐Br content (BMI‐Br‐10 CPE) exhibits significant ionic conductivity (σ = 2.34 × 10−3 S cm−1 at 30 °C), wide window (up to 4.57 V), and flame retardancy. Furthermore, the BMI‐Br‐10 CPE demonstrates galvanostatic lithium plating stripping cycling stability at 100 and 300 µA cm−2 for 800 and 500 h against Li‐metal, respectively, without a significant overpotential shooting. Furthermore, at 60 °C, the BMI‐Br‐10 CPE in [LiFePO4/BMI‐Br‐10/Li] batteries demonstrates an initial capacity of 146.9 mAh g−1, capacity retention of 99.7% and high coulombic efficiency (99.5%) after 300 cycles at 1C.

Transition from Vogel-Fulcher-Tammann to Arrhenius Ion-Conducting Behavior in Poly(Ethyl Acrylate)-Based Solid Polymer Electrolytes via Succinonitrile Plasticizer Addition

Solid polymer electrolytes (SPEs) offer potential advantages over liquid electrolytes, including flexibility, safety, and processability. However, they suffer from low room-temperature ionic conductivity. Recently, it has been reported a poly(ethyl acrylate) based (polyEA) SPE, by incorporating 50 wt% of succinonitrile (SN) solid plasticizer, 30 wt% of lithium salt and 5 wt% of fluoroethylene carbonate additive, which achieves a high room-temperature ionic conductivity of 1.01 × 10−3 S cm−1 (Nat. Nanotechnol, 2022, 17, 768-776). This novel SPE exhibits stability against Li0 and anodic stability up to 4.9 V vs Li+/Li. However, the specific mechanism responsible for its high ionic conductivity remains elusive. In this work, by adjusting the weight ratio of SN in the SPE, a transition from Vogel-Fulcher-Tammann to Arrhenius ion-conducting behavior is observed. It is demonstrated that the addition of SN leads to the gradual decoupling of Li-ion from the polymer backbone and its coordination with SN, as revealed by 6Li solid-state nuclear magnetic resonance spectroscopy. As a result, Li-ion migration primarily occurs through SN rather than the segmental motion of the polymer backbone. Performances of the SPE in Cu||Li, Li||Li and a LiFePO4||Li pouch cells are shown to demonstrate the commercial viability of this SPE in Li0-anode solid-state batteries.

Effect of nano Al2O3 addition on cycling performance of poly(ether block amide) based solid-state lithium metal batteries

A novel poly(ether block amide) (PEBA) based solid-state polymer electrolyte (SPE) was prepared using a casting method, in which 20wt% lithium (Li) bis-(trifluoromethanesulfonyl)imide (LiTFSI) and aluminum oxide (Al2O3) nanoparticles were used as the Li salt and solid plasticizer, respectively. In the case of addition of 3wt% Al2O3 nanoparticles, ion conductivity of the obtained PEBA 2533–20wt% LiTFSI-3wt% Al2O3 SPE was 3.57 × 10−5 S cm−1 at 25 °C. Furthermore, the Li symmetrical battery assembled with it showed excellent cycling stability (1000 h) at 0.1 mA cm−2. While, the assembled all-solid-state Li/PEBA 2533–20% LiTFSI-3wt% Al2O3/LiFePO4 (areal capacity: 0.15 mAh cm−2) battery maintained 94.9% of the maximal capacity (133.9 mAh g−1@0.1 mA cm−2) at 60 °C even after 650 cycles with a superior average coulombic efficiency (CE) of 99.84%. By using X-ray photoelectron spectroscope (XPS), self-aggregation layer (SAL) of polyamide 12 (PA12) of PEBA 2533 was discovered, which should contribute to promoting the robustness of lithium fluoride (LiF) enriched solid-electrolyte interphase (SEI) layer. In addition, it is considered that the state of interface between SPE and cathode should be the cause of voltage polarization of the full cell.

Facilitating ionic conductivity and interfacial stability via oxygen vacancies-enriched TiO2 microrods for composite polymer electrolytes

Composite polymer electrolyte is viewed as one of the most competitive systems for the next generation in electrolytes for solid-state Li-metal batteries, owing to its favorable flexibility, favoring interfacial contact and low cost. However, the composite polymer electrolyte suffers from low ion conductivity and interfacial stability. Herein, we propose morphology and defect control strategies to successfully prepare oxygen vacancies-enriched 1D-structured TiO2 fillers to optimum ionic conductivity and interfacial strength of the CPEs. Various electrochemical characterizations and density functional theory (DFT) calculations reveal that the induced oxygen vacancies on the TiO2 surface help dissociate LiTFSI and produce more free Li ions. Notably, the 1D-structured TiO2 microrods not only act as a solid plasticizer to increase the amorphous phases of PEO matrix but also provide continuous interaction surfaces for strong anion adsorption to promote homogenous environment and ensure interfacial stability. Benefiting from this novel design, the symmetric Li//Li cell exhibits an ultra-long lifespan stable cycling over 1000 h at 0.2 mA cm−2. Besides, solid-state lithium metal batteries with LiFePO4 cathode exhibit superior cyclability (162.4 mAh g−1 at 0.33C after 200 cycles) and rate capability (132 mAh g−1 at 2C). This work provides a promising strategy of conduction structures for delicately designing advanced solid-state electrolytes, demonstrating the promise of developing all-solid-state Li-metal batteries.

Segmental Motion Adjustment of the Polycarbonate Electrolyte for Lithium-Metal Batteries.

Carbonyl oxygen atoms are the primary active sites to solvate Li salts that provide a migration site for Li ions conducting in a polycarbonate-based polymer electrolyte. We here exploit the conductivity of the polycarbonate electrolyte by tuning the segmental motion of the structural unit with carbonyl oxygen atoms, while its correlation to the mechanical and electrochemical stability of the electrolyte is also discussed. Two linear alkenyl carbonate monomers are designed by molecular engineering to combine methyl acrylate (MA) and the commonly used ethylene carbonate (EC), w/o dimethyl carbonate (DMC) in the structure. The integration of the DMC structural unit in the side chain of the in situ constructed polymer (p-MDE) releases the free motion of the terminal EC units, which leads to a lower glass-transition temperature and higher ionic conductivity. While pure polycarbonates are normally fragile with high Young's modulus, such a prolonged side chain also manipulates the flexibility of the polymer to provide a mechanical stable interface for Li-metal anode. Stable long-term cycling performance is achieved at room temperature for both LiFePO4 and LiCoO2 electrodes based on the p-MDE electrolyte incorporated with a solid plasticizer.

PVDF-HFP Based Composite Solid Electrolyte for High Voltage NCM811 Solid-State Li-Metal Battery (SSLMB)

The composite solid electrolytes (CSEs) have attracted considerable attention because of their excellent flexibility and good compatibility with electrode materials. Our CSE was prepared by incorporating LLZO ceramic filler, lithium salt, and different concentrations of a solid plasticizer in a poly (vinylidene fluoride hexafluoropropylene) (PVDF-HFP) polymer matrix. Afterwards, we examined the ionic conductivity and electrochemical stability of the CSE, and its interfacial compatibility with a Li-metal electrode. Optimized wt.% plasticizer with CSE exhibits a high ionic conductivity of 4.23 × 10–4 and 8.14 × 10–4 S cm–1 at 25 and 60 °C, respectively, with an excellent stability of up to 4.76 V vs. Li/Li+. The CSE is sandwiched between the Li-metal anode and NCM811 cathode for the fabrication of a solid-state battery (SSB), which provides a discharge capacity (163 mAh g–1) at a rate of 0.2 C (60 °C). The LiNbO3 (LNO) surface modification over the NCM811 cell provides a high discharge capacity of 198 mAh g–1, excellent rate capability, and good cycle life. Moreover, the LNO coating on the surface of the NCM811 cathode, which effectively increases the contact between the cathode and electrolyte, eventually leads to an increase in the discharge capacity. Hence, the prepared CSE is a good choice for use in SSB; moreover, the LNO coating noticeably improved the cycling stability, reversibility, and rate capability compared to a pristine NCM811 cathode in the SSB configuration.

Structural, Thermal, and Electrical Properties of Poly(Ethylene Oxide)-Tetramethyl Succinonitrile Blend for Redox Mediators.

An all-solid–state dye-sensitized solar cell is one of the non-fossil fuel-based electrochemical devices for electricity generation in a high-temperature region. This device utilizes a redox mediator, which is a fast ion-conducting solid polymer electrolyte (SPE). The SPE makes the device economical, thinner, and safer in high-temperature regions. The SPE generally has a form of matrix−plasticizer−redox salts. Succinonitrile (SN) is generally employed as a plasticizer for reducing the crystallinity of poly(ethylene oxide), abbreviated as PEO, a common polymeric matrix. In the present paper, the structural and thermal properties of tetramethyl succinonitrile (TMSN) were compared with SN for its application as a solid plasticizer. TMSN and SN both are plastic crystals. TMSN has four methyl groups by replacing the hydrogen of the SN, resulting in higher molecular weight, solid–solid phase transition temperature, and melting temperature. We thoroughly studied the structural, thermal, and electrical properties of the [(1−x)PEO: xTMSN] blend for utilizing it as a matrix, where x = 0–0.25 in mole fraction. The FT-IR spectra and XRD patterns of the blends exhibited PEO-alike up to x = 0.15 mole and TMSN-alike for x > 0.15 mole. Differential scanning calorimetry revealed formation of a eutectic phase from x = 0.1 mole and phase separation from x = 0.15 mole. The blends with x = 0.1–0.15 mole had a low value of PEO crystallinity. Thermogravimetric analysis showed thermal stability of the blends up to 75 °C. The blends exhibited electrical conductivity, σ25°C more than 10−9 S cm−1, and Arrhenius behavior (activation energy, ~0.8 eV) in a temperature region, 25–50 °C.

Uniting printability and self-supportability of cordierite precursor pastes for fabricating cordierite ceramics with custom structures via supportless stereolithography

Cordierite precursor pastes including talc, alumina and silica particles were successfully prepared to fabricate porous cordierite ceramics by supportless stereolithography (SLA). To combining the printability and self-supportability properties of the pastes, the effects of the type and content of the dispersant on the rheological behavior were systematically investigated. Additionally, the effects of solid loading and plasticizer type on the rheological behavior of the cordierite precursor pastes were studied. It was found that 1 wt% Span80 was optimal for modifying the rheological behavior of the cordierite precursor pastes. Furthermore, the results indicated that the printability deteriorated, and the hysteresis area and yield stress of the cordierite precursor pastes increased rapidly when the solid loading exceeded 33 vol%. With the addition of 18 vol% plasticizers to replace UV-curing resins, dibutyl phthalate (DBP) was more effective in improving the printability of cordierite precursor pastes and ensuring self-supportability, compared with the polyethylene glycol 400 (PEG400). Finally, using the optimized cordierite precursor pastes, the porous cordierite ceramics with custom structures were successfully prepared.

A Ceramic Rich Quaternary Composite Solid-State Electrolyte for Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries are one of the most promising candidates to take over the traditional liquid-based lithium ion batteries as they not only allow us to circumvent safety issues but also boost energy density far over the current limits imposed by the present chemistries. We have recently demonstrated that the combination of highly conductive inorganic solid electrolyte (ISE), Li0.33La0.55TiO3 (LLTO), with the mechanically durable solid polymer electrolyte (SPE), polyethylene oxide: Lithium bis(trifluoromethanesulfonyl)imide (PEO:LiTFSI), alongside a solid plasticizer, Succinonitrile, has proved to be successful in making highly performing polymer-rich (70% polymer) quaternary composite solid electrolytes (CSEs) that evade both the brittleness of ceramics and the poor conductivity of polymers. Herein, we extend the work to ceramic rich quaternary CSEs (70% ceramic). Ceramic-rich films were fabricated using tape casting technique and have reasonable ionic conductivity of 1.5 × 10−4 S cm−1 at 55 °C, decent mechanical properties and displays impressive endurance in Li ∣∣ Li symmetrical cells (> 800 h). Solid-state coin-type cells assembled with composite cathode show satisfactory cycling performance at 0.05 C and 55 °C reaching specific discharge capacity of 160.6 mAh g−1, maintaining high Coulombic efficiency (> 95%) and high capacity retention of 90.3% after 30 cycles.

Composite Solid Electrolyte for High Voltage Solid‐State Li‐Metal Battery

AbstractA composite solid electrolyte (CSE) was prepared by incorporating Li7La3Zr2O12 (LLZO) particles, lithium bis(trifluoromethanesulfonyl) imide (LiTFSI), and different concentrations of a solid plasticizer in a poly(vinylidene fluoride hexafluoropropylene) (PVDF‐HFP) matrix. Subsequently, we investigated the ionic conductivity and electrochemical stability of the CSE, and its interfacial compatibility with a Li‐metal electrode. 30 wt.% plasticizer with CSE exhibits a high ionic conductivity of 4.23×10−4 and 8.14×10−4 S cm−1 at 25 and 60 °C, respectively, with an excellent stability of up to 4.76 V vs. Li/Li+. The CSE is sandwiched between the Li‐metal and NCM811 for the fabrication of a solid‐state battery (SSB), which delivers a discharge capacity (163 mAh g−1) at a rate of 0.2 C (60 °C). The LiNbO3 (LNO) modification over the NCM811 cell delivers a high discharge capacity of 198 mAh g−1, excellent rate capability, and good cycle life. Furthermore, the LNO coating on the surface of the NCM811 cathode, which effectively improves the contact between the cathode and electrolyte, eventually leads to an increase in the discharge capacity. Therefore, the prepared CSE is a good choice for use in SSB; moreover, the LNO coating noticeably improved the cycling stability, reversibility, and rate capability compared to an unmodified NCM811 cathode in the SSB configuration.

Tetramethyl Succinonitrile as a Solid Plasticizer in a Poly(ethylene oxide)8 -LiI-I2 Solid Polymer Electrolyte.

Dye-sensitized solar cell (DSSC) is a promising alternative to the commercially available amorphous silicon-based solar cell because of several advantageous properties. A DSSC with a fast ion conducting solid polymer electrolyte is required for the arid atmosphere of Gulf countries. In this work, a new matrix, poly(ethylene oxide)-tetramethyl succinonitrile blend to synthesize a blend-LiI-I2 solid polymer electrolyte for the DSSC application has been proposed. The tetramethyl succinonitrile is a member of plastic crystal with a solid-solid phase transition temperature (Tpc ) of ≈71°C and melting temperature (Tm ) of ≈170.5°C. Its molar fraction, 0.1-0.15 is sufficient enough for synthesizing a polymer electrolyte with electrical conductivity of >10-4 S cm-1 at room temperature. This electrolyte shows Vogel-Tamman-Fulcher type behavior with a low value (≈0.083eV) of pseudo-activation energy for easy ion transport. The results of Fourier-transform infrared spectroscopy, X-ray diffractometry, and differential scanning calorimetry studies reveal the plasticizing effect of tetramethyl succinonitrile to form an amorphous phase. This electrolyte results in a ≈661% gain in short-circuit current density and thereby a ≈552% gain in the cell efficiency (≈3.5%) with respect to the DSSC prepared with the tetramethyl succinonitrile-free electrolyte.

Contribution Succinonitrile Additive for Performa LiTFSi Solid Polymer Electrolytes for Li-Ion Battery

The purpose of this study is to evaluate the performance of Solid Polymer Electrolyte (SPE) which has the role of replacing liquid electrolyte in the battery system to reduce leakage. Evaluation of electrochemical SPE consisted of mixture lithium salt, solid plasticizer, and polymer precursor with different ratio. Impedance spectroscopy was used to investigate ionic conduction and dielectric response lithium bis(trifluoromethane)sulfony imide (LiTFSI) salt, and additive succinonitrile (SCN) plasticizer. The result showing enhanced high ionic conductivity. In half-cell configurations, wide electrochemical stability window of the SPE has been tested. The great potential of SPE for applications in lithium-ion batteries can be seen from the ability of window stability at room temperature. Additive SCN contributes to forming pores that make it easier for the Li-ion to move from the anode to the cathode and vice versa for better perform SPE. Pore of SPE has been characterization with FE-SEM. Additive 50% w.t SCN shows the best ionic conductivity with 4.2 volt wide stability window and pretty much invisible pores.

Mechanical property-reinforced PEO/PVDF/LiClO4/SN blend all solid polymer electrolyte for lithium ion batteries

The use of all solid polymer electrolyte (ASPE) is an effective way to ensure the safety of lithium ion batteries, however, the low room-temperature conductivity and poor mechanical properties limit its application. The addition of succinonitrile (SN), a solid plasticizer, can improve the ionic conductivity of ASPEs, but the mechanical performance is inevitably sacrificed. To address this issue, a kind of ASPE with PEO/PVDF/LiClO4/SN blend is proposed in this work, which utilizes microporous PVDF film as a support layer. To prepare such membrane, PEO/PVDF/LiClO4/SN solution is uniformly dripped onto PVDF film surface under negative pressure, which in turn infiltrates in and partially dissolves the PVDF film, followed by self-assembly between PVDF within solution and PVDF film, and thus forming the dense membrane with excellent mechanical properties. Taking the sample with 15% LiClO4 and 15% PEO as an example, its maximum stress is 10 times higher than conventional PEO based membrane without PVDF supporting layer. Besides, the prepared ASPE membrane shows superior ionic conductivity, thermal stability and electrochemical stability window, which in turn leads to good initial discharge capabilities in LiFePO4/ASPE/Li cells at ambient-temperature.

A Polymer-Rich Quaternary Composite Solid Electrolyte for Lithium Batteries

All-solid-state batteries continue to grow as an alternative to replace the traditional liquid-based ones not only because they provide increased safety but also higher power and energy densities. However, current solid-state electrolytes are either ceramics that are brittle but highly conducting (e.g. Li0.33La0.55TiO3, LLTO) or polymer electrolytes that are poorly conducting but form flexible films with desired mechanical properties (e.g. Poly(ethylene oxide):Lithium bis(trifluoromethanesulfonyl)imide, PEO:LiTFSI). In this work, we have developed quaternary composite solid-state electrolytes (CSEs) to combine the benefits of the two types along with Succinonitrile (SN) as a solid plasticizer. CSEs with different compositions have been fully characterized over the whole compositional range. Guided by neural network simulation results it has been found that a polymer-rich CSE film gives the optimal ionic conductivity (>10−3 S cm−1 at 55 °C) and mechanical properties (Tensile strength of 16.1 MPa; Elongation-at-break of 2360%). Our solid-state coin-type cell which employs our in-house made cathode shows good cycling performance at C/20 and 55 °C maintaining specific discharge capacity at 143.2 mAh g−1 after 30 cycles. This new approach of formulating quaternary CSEs is proven to give the best combination of properties and should be universal and be applied to other CSEs with different chemistry.