Poly Vinylidene Fluoride-hexafluoropropylene Research Articles

Tailoring porous structure in non-ionic polymer membranes using multiple templates for low-cost iron-lead single-flow batteries

Porous ion-selective membranes are promising alternatives for the expensive perfluorosulfonic acid membranes in redox flow batteries. In this work, novel non-ionic porous polyvinylidene fluoride-hexafluoro propylene membranes are designed for iron-lead single-flow batteries. The membranes are prepared using a multiple template approach, involving simultaneously using polyethylene glycol and dibutyl phthalate (DBP) as pore-forming templates. Their porous structure is finely tuned by adjusting the ratio of the two templates. As a result, dual-porous membranes bearing both macro and micropores are obtained. The H3520 membrane with modified porous structure attains a high proton conductivity of 43.5 mS·cm-1 and a relatively low ferric ion diffusion constant (8.61 × 10-8 cm2·min-1) and demonstrates the best balance between these performance-determining parameters (selectivity 5.04 × 105 S·min·cm-3, higher than that of the N115 membrane). Besides, performance tests of the iron-lead single-flow single cells equipped with the dual-porous membranes show a high energy efficiency, exceeding 87.2% at its rated current density, and outstanding cycling stability over 200 charge-discharge cycles. Altogether, the mixed template method presents a promising strategy to prepare high-performance and low-cost non-ionic membranes for redox flow batteries.

Constructing an All Solid-state Flexible Lithium-Manganese Battery with High Performance

Abstract Due to a lack of portable flexible power supply, flexible electronic products can still not be applied in a large scale, particularly in the high energy density devices. To resolve this issue, flexible solid-state lithium batteries with a high safety, excellent mechanical property, and high energy densit，is proposed. In this paper, a flexible solid-state lithium-manganese battery is developed, which is assembled with a lithium cloth composite anode, a composite solid-state electrolyte poly (vinylidene fluoride)-hexafluoropropylene (PVDF-HFP)/Li6.4La3Ta0.6O12 (LLZTO), and a composite cathode (Fe ion-doped MnO2-carbon cloth). To improve the conductivity and stability of cathode, a mixture of conductive carbon black (Super P) and sodium alginate (SA) is employed. To ensure the high capacity and low price, the MnO2-based cathode is used.The obtained solid state batteries can deliver an initial capacity of 275.9 mAh g-1 at a current density of 1 C and a capacity retention of 57.9% (159.7 mAh g-1 ) after 1000 cycles. Also the produced flexible punch cell can light up the light-emitting diode(LED), and its capacity is 0.58 mAh cm-2 after 100 cycles at current density of 0.2 C.

Piezo-enhanced photocatalysis of MoS2/Bi4O5Br2/PVDF-HFP film for wastewater purification

To date, the piezoelectric field has been demonstrated as a promising approach to inhibit the recombination of photogenerated carrier in photocatalyst applications. Herein we propose a MoS2/Bi4O5Br2/PVDF-HFP piezo-photocatalytic film in the organic pollutants remediation. MoS2/Bi4O5Br2 as the photocatalytic material is incorporated to poly(vinylidene fluoride)-hexafluoro propylene (PVDF-HFP) as the supporting layer via a simple phase transition method. The polarised electric field generated on PVDF-HFP and MoS2/Bi4O5Br2 under aeration synergised with the built-in electric field formed between MoS2/Bi4O5Br2 Z-scheme heterojunction to promote the interfacial charge transfer. The degradation rates of rhodamine B (RhB) and tetracycline hydrochloride (TC) under aeration and visible light irradiation in 60min reached 98.9% and 92.2%, respectively. Meanwhile, density functional theory calculations (DFT) further demonstrated the effective charge separation and transfer induced by the Z-scheme charge transfer mechanism constructed by MoS2 composite with Bi4O5Br2, as well as the synergistic effect of the double electric field in favour of suppressing carrier recombination. This work provides an interesting solution for effectively combining piezoelectric catalysis with photocatalysis.

Polymer solid electrolytes with ultra-stable cycles and high-capacity retention for all-solid-state Li-metal battery

Polymer electrolytes have become widely popular on account of their low expenses, reduced weight, simple processing, and excellent safety features. However, polymer electrolytes have yet to find use in commercial batteries because of their limited mechanical durability and poor ionic conductivity. In this paper, an ultra-stable cycles and interfaces blending polymer electrolyte (BPE) suitable for all solid-state Li metal batteries was prepared by blending three polymers: polymethyl methacrylate (PMMA), polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), and polyethylene oxide (PEO). Microstructure characterization showed numerous amorphous areas with strong interfacial strength of the BPE. The BPE3 exhibited a maximum of 15.65 MPa in tensile strength. BPE2 have excellent electrochemical performance, such as wide electrochemical windows (up to 4.7 V vs Li/Li+), high lithium ion transference numbers (up to 0.75), high ion conductivity (up to 1.87 × 10-4 S cm−1 at 60 °C), and excellent interface stability. By assembling all state-solid LiFePO4/BPE2/Li batteries for electrochemical testing, BPE2 exhibit high electrochemical characteristics. BPE2 discharge specific capacity is as high as 154.7 mAh g−1 at 1C. The BPE2 underwent 200 cycles at 0.5C and 400 cycles at 1C, with capacity retention rates of 95.7 % and 96.6 %, respectively. BPE is a promising electrolyte candidate for flexible lithium metal batteries.

High performance solid state lithium batteries with a continuous homogeneous Li+ transmission channels

Solid state lithium batteries have been encountering a bottle neck of high solid-solid interface resistance of the membrane/electrode assembly, which is one industrial pain point. Herein, the composite solid electrolyte materials were designed and prepared to act as the double functions of solid state electrolyte membrane and the electrode binder for constructing a continuous homogeneous Li+ transmission channels with high compatibility and ionic conductivity. Firstly, dopamine was oxidized and self-polymerized on the surface of polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) to form a polydopamine (PDA) active layer, and the zwitterionic betaine sulfonate (SB) was chemically grafted onto the PDA active layer by Michael addition reaction. Secondly, the composite solid electrolyte materials were prepared by mixing the resultant SB-modified PVDF-HFP was mixed with different contents (0 %, 10 %, 20 %, 30 %) of Li6.75La3Zr1.75Ta0.25O12 (LLZTO) and 20 % bis(trifluoromethane) sulphonyl lithium (LiTFSI). Finally, a series of composite solid electrolyte membranes were prepared by scraping method and labeled as 0%LLZTO/SB-PVDF-HFP/LiTFSI, 10%LLZTO/SB-PVDF-HFP/LiTFSI, 20 %LLZTO/SB-PVDF-HFP/LiTFSI, 30%LLZTO/SB-PVDF-HFP/LiTFSI, respectively. As expected, the cell with optimal 20 %LLZTO/SB-PVDF-HFP/LiTFSI as the solid electrolyte membrane and the electrode binder delivered the reversible capacity of 135.2 mAh/g at 1.0C and maintained high capacity retention of 94.8 % for 200 cycles. The construction of the continuous and homogeneous ion transmission channels should be responsible for high Li-storage performances by improving the interface compatibility of the membrane/electrode assembly and promoting the Li+ transmission.

Multiscale Polyvinylidene Fluoride/Magnesium–Aluminum Layered Double Hydroxide Gel Electrolytes for Lithium Batteries

A multiscale of porous polyvinylidene fluoride–hexafluoropropylene copolymer/magnesium–aluminum layered double hydroxides (MgAl‐LDHs) composite gel polymer electrolyte is prepared by phase separation method. It is discovered that the ionic conductivity of the electrolyte reaches a maximum value of 1.36 × 10−3 S cm−1, the lithium ions’ mobility is 0.66, and the chemical performance is steady within the 4.85 V window along with the concentration of MgAl‐LDHs up to 0.4 wt% at room temperature. The density functional theory calculations show that the adsorption energy of Li+ with MgAl‐LDH is −3.59 eV and the diffusion potential barrier is 0.37 eV, which is favorable for the dissociation and transport of Li+. Moreover, the anode's initial discharge capacity at 0.1 C achieves 144 mAh g−1, keeping 84.7% of the theoretical capacity of 170 mAh g−1, and the capacity retention and the columbic efficiency maintain 92.4% and 95.7% after 100 cycles at 0.2 C, respectively, through assembling into a Li/PVP–MgAl/LiFePO4 battery.

Constructing Enhanced Composite Solid-State Electrolytes with Sb/Nb Co-Doped LLZO and PVDF-HFP

Composite solid-state electrolytes are viewed as promising materials for solid-state lithium-ion batteries due to their combined advantages of inorganic solid-state electrolytes and solid-state polymer electrolytes. In this study, the solid electrolytes Li6.7−xLa3Zr1.7−xSb0.3NbxO12 (LLZSNO) with Sb and Nb co-doping were prepared by a high-temperature solid-phase method. Results indicate that Sb/Nb co-doping causes lattice deformation in LLZO and increases the lithium vacancy concentration and conductivity of LLZO. Then, with the co-doped LLZSNO as an inorganic filler, a composite solid electrolyte of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) was prepared with a casting method. The obtained composite solid electrolyte exhibits a high ionic conductivity of 1.76 × 10−4 S/cm at room temperature, a wide electrochemical stable window of 5.2 V, and a lithium-ion transfer number of 0.32. The Li|LiFePO4 coin battery with the composite solid electrolyte shows a high specific capacity of 161.2 mAh/g and a Coulombic efficiency close to 100% at 1 C. In addition, the symmetrical lithium battery Li|Li with the composite electrolyte could cycle stably for about 1500 h without failure at room temperature.

Plant‐Inspired Dual‐Functional Sensor for Monitoring Pulse and Sweat Volume

AbstractWearable health monitoring sensors, when employed to monitor pulse and sweat volume in real‐time during human physical activity, serve as an effective preventative measure against abnormal health conditions, such as elevated heart rate or excessive dehydration. Herein, a dual‐functional sensor based on a sandwich structure composed of polyvinylidene fluoride hexafluoropropylene / conductive carbon black perforated film (named PCp film) and corncob sponge is designed to monitor pulse and sweat volume. The PCp film prepared by the breath figure method serves as a piezoresistive sensor with high sensitivity (0.06 kPa−1), a fast response time (0.9 ms), and high reusability for pulse monitoring. Furthermore, the PCp film has excellent water permeability (27.3 L m−2 h−1); thus, the sweat permeating through the PCp film can be absorbed by the corncob sponge. The sandwich‐structured capacitive sensor is also highly sensitive (6.021 pF nL−1) to the absorbed sweat and is highly reusable. In addition, the dual‐functional sensor is successfully integrated into a sports bracelet system to display real‐time pulse and sweat‐volume data of the wearer. This approach provides a dependable foundation for the advancement of multifunctional sensors in the field of sports monitoring.

Flexible Composite Electrolyte Membranes with Fast Ion Transport Channels for Solid-State Lithium Batteries.

Numerous endeavors have been dedicated to the development of composite polymer electrolyte (CPE) membranes for all-solid-state batteries (SSBs). However, insufficient ionic conductivity and mechanical properties still pose great challenges in practical applications. In this study, a flexible composite electrolyte membrane (FCPE) with fast ion transport channels was prepared using a phase conversion process combined with in situ polymerization. The polyvinylidene fluoride-hexafluoro propylene (PVDF-HFP) polymer matrix incorporated with lithium lanthanum zirconate (LLZTO) formed a 3D net-like structure, and the in situ polymerized polyvinyl ethylene carbonate (PVEC) enhanced the interface connection. This 3D network, with multiple rapid pathways for Li+ that effectively control Li+ flux, led to uniform lithium deposition. Moreover, the symmetrical lithium cells that used FCPE exhibited high stability after 1200 h of cycling at 0.1 mA cm-2. Specifically, all-solid-state lithium batteries coupled with LiFePO4 cathodes can stably cycle for over 100 cycles at room temperature with high Coulombic efficiencies. Furthermore, after 100 cycles, the infrared spectrum shows that the structure of FCPE remains stable. This work demonstrates a novel insight for designing a flexible composite electrolyte for highly safe SSBs.

MOF-silsesquioxane synergistic modified hybrid porous membrane for high-performance and high-safety lithium battery

As an emerging alternative separator, electrospun PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene) has been widely studied in lithium battery over the years. However, some shortcomings of PVDF-HFP have limited its further application, such as, poor thermal stability, mechanical and electrochemistry properties. In this work, the cage-like silsesquioxanes (CSQ) and metal–organic-framework (MOF) were chemically bound to PVDF-HFP, and a modified hybrid fibrous membrane with hierarchical pore was fabricated. These hybrid groups were successfully introduced into the backbone of PVDF-HFP, which was not only demonstrated by characterization of their chemical structures, and also demonstrated by morphologies and elemental mass spectrometry with the help of scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). Due to the incorporation of these hybrid groups, the membrane exhibited high thermal stabilities and good flame-retardant performance, and could also play an important role in regulating and improving the migration property of lithium ions and interface performance between electrolyte and electrodes during battery charging/discharging process.

Porous Structure of Polymer Films Optimized by Rationally Tuning Phase Separation for Passive All-Day Radiative Cooling.

Passive all-day radiative cooling (PARC) films with porous structures prepared via nonsolvent-induced phase separation (NIPS) have attracted considerable attention owing to their cost-effectiveness and wide applicability. The PARC performances of the films correlate with their porous structures. However, the porous structure formed using the NIPS process cannot be finely regulated. In this study, we prepared polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) films with porous structures optimized by rationally tuning the phase separation, which was achieved by adjusting the proportions of two good solvents with varying solubility parameters. The optimized PVDF-HFP film with a hierarchically porous structure exhibited a high solar reflectance of 97.7% and an infrared emissivity of 96.7%. The film with excellent durability achieved an average subambient cooling temperature of approximately 5.4 °C under a solar irradiance of 945 W·m-2 as well as a temperature of 11.2 °C at nighttime, thus demonstrating all-day radiative cooling. The results indicate that the proposed films present a promising platform for large-scale applications in green building cooling and achieving carbon neutrality.

Designing Compatible Ceramic/Polymer Composite Solid-State Electrolyte for Stable Silicon Nanosheet Anodes.

The commercialization of silicon anode for lithium-ion batteries has been hindered by severe structure fracture and continuous interfacial reaction against liquid electrolytes, which can be mitigated by solid-state electrolytes. However, rigid ceramic electrolyte suffers from large electrolyte/electrode interfacial resistance, and polymer electrolyte undergoes poor ionic conductivity, both of which are worsened by volume expansion of silicon. Herein, by dispersing Li1.3 Al0.3 Ti1.7 (PO4 )3 (LATP) into poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP) and poly(ethylene oxide) (PEO) matrix, the PVDF-HFP/PEO/LATP (PHP-L) solid-state electrolyte with high ionic conductivity (1.40 × 10-3 Scm-1 ), high tensile strength and flexibility is designed, achieving brilliant compatibility with silicon nanosheets. The chemical interactions between PVDF-HFP and PEO, LATP increase amorphous degree of polymer, accelerating Li+ transfer. Good flexibility of the PHP-L contributes to adaptive structure variation of electrolyte with silicon expansion/shrinkage, ensuring swift interfacial ions transfer. Moreover, the solid membrane with high tensile limits electrode structural degradation and eliminates continuous interfacial growth to form stable 2D solid electrolyte interface (SEI) film, achieving superior cyclic performance to liquid electrolytes. The Si//PHP-L15//LiFePO4 solid-state full-cell exhibits stable lithium storage with 81% capacity retention after 100 cycles. This work demonstrates the effectiveness of composite solid electrolyte in addressing fundamental interfacial and performance challenges of silicon anodes.

Self-Cleaning and Spectral Selective Membrane for Sustainable Radiative Cooling.

Radiative cooling materials have attracted great attention due to their superiority in energy-free cooling, especially for outdoor applications. However, outdoor cooling performance is threatened by surface pollution. Herein, we demonstrate a ternary compound system, including polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), boron nitride nanosheets (BNNS), and hydrophobic silicon dioxide (SiO2), to synchronously achieve self-cooling and self-cleaning properties through biomimetically building a lotus-like papillomatous structure. The optimized membrane has a high infrared emissivity of 0.93, a sunlight reflectivity of 97.2%, and a water contact angle of 150.5°and not only efficiently cools the object to a suitable temperature but also protects the membrane from polluting and keeps cooling for a long time. The result shows that the membrane can cool a nonfebrile object by 30.5 and 1.7 °C for noon and night, respectively, and the noon and night-time temperature drops are 10.8 and 13.5 °C for the self-heating object, compared to the bare state. Meanwhile, the membrane always keeps self-cleaning if slurry is splashed onto its surface or it is exposed to slurry. Importantly, the integration of superhydrophobic and radiative cooling properties ensures that the membrane has permanent cooling performance by protecting it from being contaminated, which is significant for outdoor applications.

Designing a multi-stage MoS2 fiber membrane for photothermal membrane distillation

Among the various desalination technologies, membrane distillation (MD) stands out for its high salt rejection, low operating temperature and operating pressure. Photothermal membrane distillation (PMD) represents an innovative approach to membrane distillation (MD), wherein the process harnesses plentiful and renewable solar energy to achieve localized heating at the interface between the membrane and the feed solution. This is achieved by employing photothermal materials, eliminating the need for heating a substantial volume of the feed solution. This study has prepared membranes with micro/nano fiber interwoven structure based on polystyrene (PS) and polyvinylidene fluoride hexafluoropropylene copolymer (PVDF-HFP) by electrospinning technology, and constructed multi-stage MoS2 photothermal fiber membranes by hydrothermal growth process. The PS/PVDF-HFP micro/nano fiber membrane possesses a spacious pore structure and high porosity, serving as a robust framework that facilitates swift transport of water vapor. The MoS2 nanoflowers uniformly grown on the micro/nano fibers have both metal 1T and semiconductor 2H phases, which facilitate the absorption of sunlight, reaching an average absorbance of 90.9 % in the240-2600 nm wavelength range. Under 1 kW m−2 solar illumination, the surface temperature of the PS/PVDF-HFP/MoS2 membrane could be raised to 74.2 °C after 120 s. The permeate flux was stable at 1.21 ± 0.02 L m−2 h−1 within 20 h PMD. The membrane showcased a salt rejection rate of 99.96 % and achieved an energy efficiency of 72.08 %. This suggests that the multi-stage MoS2 photothermal fiber membrane, characterized by remarkable stability and high photothermal conversion efficiency, lays a solid foundation for advancing research in the field of PMD applications.

In-situ construction of a hybrid interfacial protective layer for highly stable Li metal anodes

Lithium (Li) metal is an ideal anode candidate for rechargeable batteries because of its ultra-high theoretical specific capacity. Unfortunately, the practical application of Li metal anodes (LMA) is severely limited by the uncontrollable formation and growth of dendrites and volume expansion. Thus, a protective layer is essential for stable and high-performance LMA. In this work, an organic-inorganic hybrid protective layer is in-situ prepared on Li foil surface (pa-Li), consisting of the organic Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and inorganic Ag-LixAgy composites. Going beyond conventional protective layers, the hybrid protective layer is flexible and enables strong interfacial adherence due to an alloying process. Furthermore, owing to the protective layer's outstanding lithiophilicity and mechanical stability, the pa-Li││pa-Li symmetric cell exhibits satisfactory stability for 1000 h at 5 mA/cm2, 5 mA h/cm2 with a low voltage hysteresis of ∼70 mV, while the full cell with a LiFePO4 cathode delivers an excellent reversible capacity of 128.9 mA h/g for 900 cycles at 2C with a capacity decay rate of 0.009 % per cycle.

Flexible pressure sensor based on multi-layer with gradient structure P(VDF-HFP)/MXene/BaTiO3 composite film for human motion monitoring

In recent years, flexible pressure sensors have been widely used in fields such as human health monitoring, flexible energy storage, wearable electronic devices, and flexible sensing due to their advantages of simple and efficient preparation process, highly sensitive, fast response, and strong piezoelectric performance. In this paper, we studied a kind of polyvinylidene fluoride hexafluoropropylene (P(VDF-HFP))/MXene/BaTiO3 nanofiber prepared by electrospinning technology, and designed a multi-layer structure system with gradient to prepare a flexible pressure sensor. The piezoelectric properties, mechanical properties and dielectric properties are obviously improved. At the same time, the addition of nano fillers and structural design have increased the sensitivity of multi-layer composite fiber membrane-based sensors by 16.5 times compared to pure P(VDF-HFP) in the low-pressure range (<1 kPa), and by 1.5 times compared to PFP-0.5M5BT nanofiber-based sensors, reaching 0.23 kPa−1. When pressed by the palm of the hand, the output voltage of the three-layer gradient structure thin film sensor can be up to about 100 V. Compared with the output voltage of 5 V when the P(VDF-HFP) thin film is pressed by the palm, the output voltage of the flexible pressure sensor of the three-layer gradient structure thin film after adding the filler is 20 times higher. The flexible pressure sensor can analyze and recognize the form of human motion based on the peak, frequency, and shape characteristics of the voltage signals generated by different forms of human motion. This makes it possible for flexible pressure sensors to be used in pressure detection, flexible sensing, electronic skin sensors and other fields.

Stable and long-life Zn anode enabled by an ion-conductive copolymer coating for rechargeable aqueous batteries

The Zn metal anode endows aqueous zinc-ion batteries (ZIBs) with merits in terms of low cost, high safety, and bivalent ions as charge carriers. Yet the current ZIB technology is immature due to some issues arising from the Zn anode, including the dendrite growth, formation of compound byproducts, and hydrogen gas evolution. Here, a nanoporous and ion-conductive polyvinylidene fluoride-hexafluoro propylene copolymer containing zinc trifluoromethanesulfonate (Zn2+-PVDF-HFP coating) is applied onto the Zn foil to improve its anode performance. The Zn anode covered with Zn2+-containing PVDF-HFP coating (Zn@Zn2+-PVDF-HEP) shows good anti-corrosion performance and much longer cycle life, compared to the bare Zn anode. Also, the byproduct growth and hydrogen gas evolution can be efficiently suppressed due to the Zn2+-conductive copolymer coating. For symmetric cells using Zn@Zn2+-PVDF-HFP, a long lifespan of 2200 cycles is achieved when tested at 1 mA cm−2 and 1 mAh cm−2. Even cycled at 10 mA cm−2 and 5 mAh cm−2, this cell can sustain for over 1800 h. The efficacies of Zn2+-PVDF-HFP coating in prolonging cycle life and enhancing areal capacity of the Zn anode are further verified in MnO2- or V2O5-based full cells, for which the mechanisms are discussed in detail.

A new type of LATP doped PVDF-HFP based electrolyte membrane with flame retardancy and long cycle stability for solid state batteries

Lithium ion batteries are a widely used high-density energy storage device due to their low self-discharge rate and lack of memory effect. However, their use in liquid electrolyte systems poses a significant safety risk due to issues such as lithium dendrite growth and toxic electrolytes that are also prone to leakage. Therefore, the development of gel polymer electrolytes (GPE) with high ionic conductivity and elevated lithium ion migration numbers is crucial to addressing these concerns. This work focuses on the preparation of flexible microporous composite gel polymer electrolytes (L-GPE) based on Polyvinylidene fluoride-Hexafluoropropylene (PVDF-HFP) and Li1.3Al0.3Ti1.7P3O12 (LATP) as a filler and on testing its performance as an electrolyte in applications of lithium ion battery. The L-GPE demonstrated an ionic conductivity of 8.13 × 10−4 S·cm−1 at 40 °C, with a lithium ion mobility number of 0.58, indicating high ionic mobility. Notably, in all-solid-state lithium ion battery applications, the L-GPE demonstrated excellent long-cycle stability, with a capacity retention of 90.3 % after 1000 cycles at 0.5C. These results demonstrate that the interaction force between LATP and anions enhances lithium ion mobility in composite gel polymer electrolytes, which is favorable for the regulation of lithium ion deposition and the control of lithium dendrite growth. Besides, the performance of this L-GPE membrane is significantly improved due to its suitable porosity, gratifying mechanical properties, and excellent flame retardancy. In summary, this strategy provides a valuable contribution to the development of safe and long-lasting energy storage systems by presenting a novel L-GPE membrane with enhanced mechanical, high ionic conductivity, excellent flame retardant property and thermal stability.

Desilicated zeolite ZSM-5 based composite polymer electrolytes for solid-state lithium metal batteries

The desilicated zeolite ZSM-5 (des-ZSM-5) based composite polymer electrolytes (CPEs) PZEw was fabricated via phase inversion processes and in-situ polymerization with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and liquid electrolyte 1 M lithium bis(trifluoromethanesulphonyl)imide (LiTFSI) in vinylene carbonate (VC) (VC@LiTFSI). Assisted by des-ZSM-5, PZEw possess excellent thermal stability, mechanical properties, high ionic conductivity (2.75 × 10−4 S cm−1, 25 °C), and enlarged electrochemical windows (4.94 v, vs. Li+/Li). Meanwhile lithium metal batteries (LMBs) LiFePO4 (LFP)/PZEw/Li showed superior rate performance and long-time cycling stability.

Stable quasi-solid-state lithium-organic battery based on composite gel polymer electrolyte and compatible organic cathode material

High-performance organic small-molecule electrode materials are troubled with their high solubility in liquid electrolytes. The construction of quasi-solid-state lithium organic batteries (LOBs) using gel polymer electrolytes with high mechanical properties, compromised ionic conductivity, high safety, and eco-friendly is an effective way to inhibit the dissolution of active materials. Herein, two hexaazatriphenylene (HATN)-based organic cathode materials (HATNA-6OCH3 and HATNA-6OH) are synthesized and then matched with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)-based gel polymer electrolytes to construct quasi-solid-state LOBs. Thanks to the enhanced interfacial compatibility between organic cathode material and gel polymer electrolyte, HATNA-6OH with compatible hydroxyl group shows the enhanced electrochemical properties compared with HATNA-6OCH3. Further, the electrochemical performance is improved when HATNA-6OH is combined with a gel polymer electrolyte modified with a succinonitrile (SN) plasticizer (GPE-0.4SN), including a high specific capacity of 153.3 mAh g−1 at 50 mA g−1 and a good reversible capacity of 88 mAh g−1 after 100 cycles at 200 mA g−1. In addition, the good electrochemical properties and lithium-ion storage mechanism of HATNA-6OH have been elucidated using density functional theory (DFT) and spectral characterizations.