High-performance Poly Research Articles

Heterocyclic polymer supported cathode/Li interface layers to lower the operational temperature of PEO-based Li-batteries

High-performance poly (ethylene oxide) (PEO)-based solid-state polymer Li-batteries (SSLBs) at low temperature (≤ 25 ℃) is hindered by high interfacial resistance and low ionic conductivity. Herein, we simultaneously construct cathode and anode interface layers via in-situ heat-induced heterocyclic polymerization reaction, where the cathode-electrolyte interface layer (PPL) consists of bromine-doped poly (3,4-ethylene-dioxy-thiophene) (PEDOT), PEO and bis-trifluoromethanesulfonimide (LiTFSI), featuring with mixed ionic/electronic conduction, and the anode-electrolyte interface layer (PVCL) was formed by poly (vinyl carbonate) (PVC), PEO and LiTFSI, having a robust fast ionic conduction. Benefiting from the PEDOT conductivity, high mechanical strength of PVC and good interface affinity aroused by heat-induced reaction, the solid-state PEO-based LiFePO4||Li cell shows low interfacial resistance of 11.02 Ω that decreased by 92% compared to the cell without interface modification, and delivering a discharge capacity of 164.4 mAh g−1 at 0.1 C (25 ℃), as high as 115.9 mAh g−1 at 10 ℃. X-ray photoelectron spectroscopy revealed the enrichment of LiF, Li3N and LiBr on the lithium metal surface after cycling, further enhancing stable cycling Li-batteries. The dual interface-constructed strategy provides a reliable way to resolve the bottle-neck interfacial issues of SSLBs.

Fabrication of high-performance poly(benzoxazole-co-imide) membrane by utilizing synergistic effect of thermal rearrangement and Zn2+ modification

Developing membranes that combine excellent gas separation performance with robust resistance to plasticization is highly demanded for membrane separation but remains a challenge. Herein, a series of Zn2+ functionalized poly(benzoxazole-co-imide) membrane was constructed via co-polymerizing (4,4′-hexafluoroisopropylidene) diphthalic anhydride (6FDA) with o-hydroxyl diamine 2,2′-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (BisAPAF) and 1,3,5-tris(4-aminophenyl)benzene (TAPB) followed by thermal rearrangement (TR) and Zn2+ modification processes. The TR conversion opened the polymer chains with larger d-spacing and higher BET surface area, thus, greatly increased the gas permeability. Meanwhile, the post Zn2+ modification resulted in a huge improved selectivity because of the π-complexation reactions between Zn2+ and CO2 and the formation of a Zn2+ coordination crosslinking network. As a result, due to the synergistic effect of TR and Zn2+ modification, the overall gas transport properties of these newly developed membranes were greatly improved. Furthermore, the dual network structures that arise from the remaining network PI and the Zn2+ coordination crosslinking contribute to the resultant membrane with excellent anti-plasticization capability. A represent membrane termed as PBOI-Zn2+-14h membrane exhibits great CO2/CH4 separation performance, delivering a CO2 permeability of 1048.1 Barrer and a CO2/CH4 selectivity of 46.1 that is exceeded the 2008 Roberson limitation. Furthermore, this membrane possesses remarkable resistance to CO2-induced plasticization, withstanding pressures above 35 Bar. Overall, this study presents an effective way for constructing polymer membranes with both high gas separation performance and strong resistance to plasticization issue.

Electrically insulating PBO/MXene film with superior thermal conductivity, mechanical properties, thermal stability, and flame retardancy

Constructing flexible and robust thermally conductive but electrically insulating composite films for efficient and safe thermal management has always been a sought-after research topic. Herein, a nacre-inspired high-performance poly(p-phenylene-2,6-benzobisoxazole) (PBO)/MXene nanocomposite film was prepared by a sol-gel-film conversion method with a homogeneous gelation process. Because of the as-formed optimized brick and mortar structure, and the strong bridging and caging effects of the fine PBO nanofibre network on the MXene nanosheets, the resulting nanocomposite film is electrically insulating (2.5 × 109 Ω cm), and exhibits excellent mechanical properties (tensile strength of 416.7 MPa, Young’s modulus of 9.1 GPa and toughness of 97.3 MJ m−3). More importantly, the synergistic orientation of PBO nanofibres and MXene nanosheets endows the film with an in-plane thermal conductivity of 42.2 W m−1 K−1. The film also exhibits excellent thermal stability and flame retardancy. This work broadens the ideas for preparing high-performance thermally conductive but electrically insulating composites.

Reinforcing Poly (Metaphenylene Isophthalamide) Fibers by Cellulose Nanocrystal

Typical poly (metaphenylene isophthalamide) fibers exhibit excellent heat resistance and excellent flame retardancy but very poor breaking strength, which limits their diversified applications severely. Therefore, it becomes urgently important to develop new strategies to improve their breaking strength. In this regard, a new composite fiber was prepared by wet spinning through a blend solution of poly (metaphenylene isophthalamide) and cellulose nanocrystals. Poly (metaphenylene isophthalamide) composite fibers with excellent breaking strength blended with cellulose nanocrystals were prepared through a simple and scalable blending strategy. In contrast to the pristine poly (metaphenylene isophthalamide) fiber, its mechanical properties were significantly improved, such as maximum breaking strength of 4.89 cN/dtex, which is 86.8% higher than pristine poly (metaphenylene isophthalamide) fiber. This work provides a new way of thinking to fabricate high-performance poly (metaphenylene isophthalamide) fibers for high-tech applications.

Dual-Coordination-Induced Poly(vinylidene fluoride)/Li6.4Ga0.2La3Zr2O12/Succinonitrile Composite Solid Electrolytes Toward Enhanced Rate Performance in All-Solid-State Lithium Batteries.

Pursuing high energy and power density in all-solid-state lithium batteries (ASSLBs) has been the focus of attention. However, due to their inferior ion transport, their rate performance is limited compared to traditional lithium-ion batteries. Herein, a dual-coordination mechanism is first proposed to construct a high-performance poly(vinylidene fluoride)/Li6.4Ga0.2La3Zr2O12/succinonitrile (PVDF/LLZO/SN) composite solid electrolyte. The dual-coordination interactions of SN with both LLZO and Li+ in lithium salts allow SN to act like a branched chain of PVDF, realizing an increase in the free volume of the composite electrolyte. Meanwhile, SN molecules are immobilized within the electrolyte membrane by coordinating with LLZO, ensuring good interfacial stability. Profiting from the dual-coordination mechanism, the PVDF/LLZO/SN composite solid electrolyte combines enhanced electrochemical performance and interfacial compatibility. When applied to ASSLBs, the composite solid electrolyte enables the battery to operate at rates up to 6 C. The LiFePO4/Li batteries operated at 4 C can still deliver a high capacity retention rate of 96.4% after 50 cycles. Notably, these batteries also exhibit good long-cycle stability. After 500 cycles at 0.5 C, the discharge capacity was maintained at 145.9 mAh g-1.

Biobased furan-functionalized high-performance poly (aryl ether ketone) with low dielectric constant and low dielectric loss

Furandicarboxylic acid is considered one of the most representative biomass matrix platforms and has been widely used to synthesize various novel biomaterials. In this study, a series of copolymerized poly (aryl ether ketone) resins with excellent properties have been prepared by combining the nonlinear structure of furan ketone with the weakly polarized cyclohexane structure. And the relationship between the structure and properties of the resins has been systematically studied. The results showed that the synthesized resins had excellent thermal properties, and the 5% thermal decomposition temperature could reach up to 478 °C. In addition, the resin exhibits good solubility and can be dissolved in the most common solvents. Its water absorption is deficient, at only 0.71%. At 10 GHz, the lowest dielectric constant of the resin is 3.05. Most importantly, using bio-based monomers in this study provides an environmentally friendly strategy for material design and synthesis, providing a green way to develop high-performance low-dielectric materials.

Improving physical properties of poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels via the Hofmeister effect

Hydrogel is a kind of three-dimensional crosslinked polymer material with high moisture content. However, due to the network defects of polymer gels, traditional hydrogels are usually brittle and fragile, which limits their practical applications. Herein, we present a Hofmeister effect-aided facile strategy to prepare high-performance poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels. Layered montmorillonite nanosheets can not only serve as crosslinking agents to enhance the mechanical properties of the hydrogel but also promote the ion conduction. More importantly, based on the Hofmeister effect, the presence of (NH4)2SO4 can endow nanocomposite hydrogels with excellent mechanical properties by affecting PVA chains' aggregation state and crystallinity. As a result, the as-prepared nanocomposite hydrogels possess unique physical properties, including robust mechanical and electrical properties. The as-prepared hydrogels can be further assembled into a high-performance flexible sensor, which can sensitively detect large-scale and small-scale human activities. The simple design concept of this work is believed to provide a new prospect for developing robust nanocomposite hydrogels and flexible devices in the future.

Thermal and tribo-mechanical properties of high-performance poly(etheretherketone)/reduced graphene oxide nanocomposite coatings prepared by electrophoretic deposition

The thermal stability and degradation, near-to-surface mechanical properties, and scratch resistance and damage mechanism of poly(etheretherketone) (PEEK)/reduced graphene oxide (RGO) nanocomposite coatings are analyzed and discussed in terms of their nanosheet content and microstructure. Although RGO modified the thermal stability and degradation of the polymeric matrix, for instance, by slightly reducing the onset degradation temperature, its addition was not a limiting factor in the PEEK processing. Respecting the microstructural features induced by the nanosheets, the nanocomposite coatings were found to exhibit (i) a partially exfoliated and large-scale co-continuous morphology related to RGO nanosheets whose basal planes were mainly aligned with the coating surface, (ii) a dendritic morphology of PEEK domains related to transcrystallinity, (iii) and irregular domains associated with the deposition of PEEK particles wrapped by the nanosheets. The changes provoked by RGO in the morphology and PEEK crystalline phase influenced the near-to-surface mechanical properties, scratch resistance, and scratch damage mechanism of the nanocomposite coatings. Within this context, the interlayer strength between the nanosheets in the large-scale co-continuous morphology and PEEK transcrystallinity had an important effect. Furthermore, the random-bumpy surface texture formed by the irregular PEEK domains together with the conformal cracking damage mechanism was decisive in the scratch response of the PEEK/RGO nanocomposite coatings. The comprehensive characterization carried out in this work concludes that PEEK/RGO electrophoretic coatings are suitable for a variety of applications requiring tribo-mechanical resistance.Graphical

High-Performance Poly(1-naphthylamine)/Mesoporous Carbon Cathode for Lithium-Ion Batteries with Ultralong Cycle Life of 45000 Cycles at -15°C.

Organic electrode materials for lithium-ion batteries have attracted significant attention in recent years. Polymer electrode materials, as compared to small-molecule electrode materials, have the advantage of poor solubility, which is beneficial for achieving high cycling stability. However, the severe entanglement of polymer chains often leads to difficulties in preparing nanostructured polymer electrodes, which is vital for achieving fast reaction kinetics and high utilization of active sites. This study demonstrates that these problems can be solved by the in situ electropolymerization of electrochemically active monomers in nanopores of ordered mesoporous carbon (CMK-3), combining the advantages of the nano-dispersion and nano-confinement effects of CMK-3 and the insolubility of the polymer materials. The as-prepared nanostructured poly(1-naphthylamine)/CMK-3 cathode exhibits a high active site utilization of 93.7%, ultrafast rate capability of 60Ag-1 (≈320C), and an ultralong cycle life of 10000 cycles at room temperature and 45000 cycles at -15°C. The study herein provides a facile and effective method that can simultaneously solve both the dissolution problem of small-molecule electrode materials and the inhomogeneous dispersion issue of polymer electrode materials.

Molecular Orientation Control of Regioisomeric Small-Molecule Acceptors for High-Performance Poly(3-hexylthiophene)-Based Organic Solar Cells with 9.3% Efficiency

Use of poly(3-hexylthiophene) (P3HT) enables low-cost manufacture of organic solar cells (OSCs). However, the power conversion efficiencies (PCEs) of the P3HT-based OSCs should be further enhanced. Herein, we report the development of noncovalently fused nonfullerene acceptors (NFAs) that realize high-performance P3HT-based OSCs (>9%). We synthesize regioisomeric NFAs (C4-In and C4-Out) in which the positions of the methyl substituents of their end groups differ. Interestingly, the molecular orientation of the regioisomers in thin film is found to change from edge-on (C4-Out) to face-on (C4-In) orientation, allowing a model study exploring the impact of the microstructure of NFAs on the performance of P3HT-based OSCs. We find that face-on oriented C4-In facilitates both electron and hole transport in a P3HT-based OSC along the vertical direction. In addition, C4-In shows reduced trap densities and suppressed charge recombination in the P3HT:C4-In OSC due to its lower energetic disorder relative to C4-Out. As a result, the P3HT:C4-In OSC (PCE = 9.35%) outperforms a P3HT:C4-Out OSC (PCE = 8.12%) owing to simultaneous enhancement in open-circuit voltage, short-circuit current density, and fill factor. This study demonstrates the importance of molecular orientation of NFAs for developing high-performance P3HT-based OSCs.

Building Tunable Degradation into High-Performance Poly(acrylate) Pressure-Sensitive Adhesives.

Pressure-sensitive adhesives (PSAs) based on poly(acrylate) chemistry are common in a wide variety of applications, but the absence of backbone degradability causes issues with recycling and sustainability. Here, we report a strategy to create degradable poly(acrylate) PSAs using simple, scalable, and functional 1,2-dithiolanes as drop-in replacements for traditional acrylate comonomers. Our key building block is α-lipoic acid, a natural, biocompatible, and commercially available antioxidant found in various consumer supplements. α-Lipoic acid and its derivative ethyl lipoate efficiently copolymerize with n-butyl acrylate under conventional free-radical conditions leading to high-molecular-weight copolymers (Mn > 100 kg mol-1) containing a tunable concentration of degradable disulfide bonds along the backbone. The thermal and viscoelastic properties of these materials are practically indistinguishable from nondegradable poly(acrylate) analogues, but a significant reduction in molecular weight is realized upon exposure to reducing agents such as tris (2-carboxyethyl) phosphine (e.g., Mn = 198 kg mol-1 → 2.6 kg mol-1). By virtue of the thiol chain ends produced after disulfide cleavage, degraded oligomers can be further cycled between high and low molecular weights through oxidative repolymerization and reductive degradation. Transforming otherwise persistent poly(acrylates) into recyclable materials using simple and versatile chemistry could play a pivotal role in improving the sustainability of contemporary adhesives.

Self-Healable Conductive Hydrogels with High Stretchability and Ultralow Hysteresis for Soft Electronics.

Stretchable sensors based on conductive hydrogels have attracted considerable attention for wearable electronics. However, their practical applications have been limited by the low sensitivity, high hysteresis, and long response times of the hydrogels. In this study, we developed high-performance poly(vinyl alcohol) (PVA)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) based hydrogels post-treated with NaCl, which showed excellent mechanical properties, fast electrical response, and ultralow hysteresis properties. The hydrogels also demonstrated excellent self-healing properties with electrical and mechanical properties comparable to those of the original hydrogel and more than 150% elongation at break after the self-healing process. The high performance of the optimized hydrogels was attributed to the enhanced intermolecular forces between the PVA matrix and PEDOT:PSS, the favorable conformational change of the PEDOT chains, and an increase in localized charges in the hydrogel networks. The hydrogel sensors were capable of tracking large human motion and subtle muscle action in real time with high sensitivity, a fast response time (0.88 s), and low power consumption (<180 μW). Moreover, the sensor was able to monitor human respiration due to chemical changes in the hydrogel. These highly robust, stretchable, conductive, and self-healing PVA/PEDOT:PSS hydrogels, therefore, show great application potential as wearable sensors for monitoring human activity.

Sewable high-performance poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/layered double hydroxide core-shell fiber electrodes for flexible supercapacitors

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based fibers are one of the most competitive fiber-type electrodes but still suffer from low electrochemical surface areas (ECSAs) and oversensitivity to humidity for fiber supercapacitor applications. Herein, through rational design, a sewable core-shell fiber electrode of PEDOT:PSS/waterborne polyurethane (WPU) fiber wrapped with nickel/cobalt-layered double hydroxides (NiCo-LDH) has been synthesized via wet-spinning and solution reaction. The fiber core acts as a conductive channel for charge carrier transport. The NiCo-LDH shell possesses unique hybrid architectures of honeycomb-like nanosheet array and hollow nanocages, which provide numerous electrochemical active sites. Simultaneously, the water barrier effect of the NiCo-LDH shell and the interaction between Co2+/Ni2+ and PSS reduce fiber water uptake, thus endowing the fiber with a better geometric stability with low swelling ratio. The as-prepared PEDOT:PSS/LDH fiber has a large ECSA (4060 cm2 g−1) and ultrahigh conductivities no matter in dry (1237.3 S cm−1) or wet (1018.7 S cm−1) state. It also exhibits a high capacitance (188.5 F g−1 at 1 A g−1) and long lifespan (capacitance retention of 94% after 10,000 cycles). The fiber-based supercapacitor shows superb flexibility with stable capacitive behavior under deformation. These characteristics manifest the potential of PEDOT:PSS/LDH fibers for stable high-performance energy storage to support wearable electronics.

Mechanistic and kinetics insights into structure sensitivity of 2,6-Diamino-3,5-Dinitropiridine hydrogenation over Ni catalysts

Designing cost-effective Ni-based catalysts with satisfactory performance for the hydrogenation of 2,6-diamino-3,5-dinitropyridine (DADNP) to 2,3,5,6-tetraaminopyridine (TAP) is highly essential for producing high-performance poly (pyridobisimidazole) but remains a great challenge due to the limited mechanistic and kinetics understandings. Herein, a series of differently sized Ni catalysts but similar electronic properties are synthesized to explore the size-dependent kinetics behaviors of the hydrogenation of DADNP via two competitive routes. The results unravel that the hydrogenation of DADNP to TAP via the route 2, i.e., the formation of TAP from the direct hydrogenation of DADNP without being intermediated by the 2,3,6-triamino-5-nitropyridine (TANP), appears to be more prominent on larger sized Ni catalysts. Microkinetics studies based on the Langmuir-Hinshelwood-Hougen-Watson model indicate that the ratio of the TAP formation rates via these two routes, i.e., k´TAP2/k´TAP1, increases with the increasing Ni particle size, confirming the more favorable formation of TAP via the route 2 on larger sized Ni catalysts. These size-dependent kinetics behaviors are further rationalized by DFT calculations, which reveal that the simultaneous activation of both nitro groups of DADNP via flat adsorption is more likely to occur on the larger size Ni catalysts than that on the smaller sized ones.

Solvent-Exchange-Assisted Wet Annealing: A New Strategy for Superstrong, Tough, Stretchable, and Anti-Fatigue Hydrogels.

Hydrogels are widely used in tissue engineering, soft robots, wearable electronics, etc. However, it remains a great challenge to develop hydrogels possessing simultaneously high strength, large stretchability, great fracture energy, and good fatigue threshold to suit different applications. Herein, a novel solvent-exchange-assisted wet-annealing strategy is proposed to prepare high performance poly(vinyl alcohol) hydrogels by extensively tuning the macromolecular chain movement and optimizing the polymer network. The reinforcing and toughening mechanisms are found to be "macromolecule crystallization and entanglement". These hydrogels have large tensile strengths up to 11.19 ± 0.27MPa and extremely high fracture strains of 1879 ± 10%. In addition, the fracture energy and fatigue threshold can reach as high as 25.39 ± 6.64kJ m-2 and ≈1233 J m-2 , respectively. These superb mechanical properties compare favorably to those of other tough hydrogels, organogels, and even natural tendons and synthetic rubbers. This work provides a new and effective method to fabricate superstrong, tough, stretchable, and anti-fatigue hydrogels with potential applications in artificial tendons and ligaments.

Cu(I) catalyzed ATRP for the preparation of high-performance poly (vinylidene fluoride)-g-poly 2-(dimethylamino)ethyl methacrylate crosslinked anion exchange membranes for enhanced acid recovery

The exclusive selectivity feature of an anion exchange membrane (AEM) makes it a core component of the diffusion dialysis (DD) process. Herein, we have developed a novel synthetic route for the preparation of AEMs with a controlled graft length and density by grafting 2-(dimethylamino)ethyl methacrylate (DMA) chains from the backbone of poly(vinylidene fluoride) (PVDF) by Cu(I) catalyzed atom transfer radical polymerization to produce PVDF-g-PDMA copolymer, which is converted to AEM by the reaction with α,α’-dichloro-p-xylene (XDC). XDC induces positive charge on the membrane surface and increases the hydrophilicity of the membrane. It also acts as a crosslinker and helps to create a network structure in the membrane, which increases overall membrane stability. The AEMs are used to separate hydrochloric acid from its mixture with metal salts by diffusion dialysis. A representative AEM containing 12% w/w PDMA, abbreviated as ATM-2, show diffusion coefficient (UH+) and separation factors (S) of 0.049 m/h and 117, respectively during the separation of HCl from 2 M HCl + 0.09 M FeCl2 solution. ATM-2 also shows higher UH+ and S values for the separation of HCl with its mixture of different metal salts, i.e., NaCl, CuCl2, and AlCl3. ATM-2 membrane endures a small loss of 1.5% and 3.2% in UH+ and S values, respectively, after submerging in a 2 M acid/salt mixture solution for 60 days. This confirms the good acid stability of the AEM. The results indicate the reasonable potency of the prepared AEMs to be a suitable candidate for DD applications.

Gas-solid fluidization modification of calcium carbonate for high-performance poly (butylene adipate-co-terephthalate) (PBAT) composites.

Modifying biodegradable poly (butylene adipate-co-terephthalate) (PBAT) plastic with inorganic fillers is critical for improving its overall performance, lowering the costs, and expanding its application scope. The chemical modification method for the inorganic filler determines the application performance of PBAT composites. In this work, gas-solid fluidization method was developed as a simple, efficient, and scalable strategy for chemically modifying CaCO3 filler. The modified CaCO3 filler was mixed with PBAT and melt extruded to prepare biodegradable PBAT/CaCO3 composites. The characterization results show that gas-solid fluidization method combines the traditional wet modification method's excellent modification effect with the scalability of the traditional dry modification method. The effects of modification methods and amount of CaCO3 filling on the crystallinity, mechanical, and rheological properties of PBAT/CaCO3 composites were compared. The results demonstrated that PBAT/CaCO3 composites containing 30% gas-solid fluidization modified CaCO3 could still maintain excellent overall performance. As a result, this work provides a simple, efficient, and scalable method for chemically modifying inorganic fillers and preparing biodegradable composites.

One-step post-treatment boosts thermoelectric properties of PEDOT:PSS flexible thin films

• High power factor of 64.4 µW m −1 K −2 is achieved in PEDOT:PSS films at 360 K. • 80 vol.% DMAC solution boosts the electrical conductivity from 5 to 964 S cm −1 . • 0.5 mol L −1 LAA improves the Seebeck coefficient from 18.7 to 25 µV K −1 . • Mott variable range hopping model explains the thermoelectric transport behavior. Developing high-performance poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) significantly widens the practical applications of flexible organic thermoelectric devices, while the water-based co-solvent dopants and/or post-treatments are still rarely studied so far. Here, we develop a one-step post-treatment to improve the power factor of PEDOT:PSS films by using a water-based solution, which is composed of co-solvent (polar solvent dimethylacetamide (DMAC) and deionized water) and organic reducing agent L-ascorbic acid (LAA). The 80 vol.% DMAC solution significantly boosts the room-temperature electrical conductivity of the films from 5 to 964 S cm −1 , while the Seebeck coefficient can be further enhanced from 18.7 to 25 µV K −1 by treating with 0.5 mol L −1 LAA, contributing to a significantly improved power factor of 55.3 µW m −1 K −2 . The boosted electrical conductivity is ascribed to the separated PEDOT and PSS phases triggered by the high dielectric constant and polarity of DMAC; while the improved Seebeck coefficient is attributed to the reduced oxidation degree of PEDOT from the reducing agent LAA, both confirmed by the comprehensive structural and morphological characterizations. Furthermore, a maximum power factor of 64.4 µW m −1 K −2 can be achieved at 360 K and the observed temperature-dependent electrical transport behavior can be well explained by the Mott variable range hopping model. Besides, a flexible thermoelectric device, assembled by the as-fabricated PEDOT:PSS films, exhibits a maximum output power of ∼23 nW at a temperature difference of 25 K, indicating the potential for applying to low-grade wearable electronics.

A facile approach towards high-performance poly(thioether-thioester)s with full recyclability

A facile approach towards high-performance poly(thioether-thioester)s with full recyclability

High-Performance Poly(vinylidene fluoride)-Based Composite Polymer Electrolytes for Lithium Batteries Based on Halloysite Nanotubes with Polyethylene Oxide Additives

Solid polymer electrolytes (SPEs) are considered to be an important move to revive high-energy-density lithium-metal batteries due to their good flexibility and high safety. However, the low room-temperature ionic conductivity of SPEs has always been a stumbling block for their practical applications. Herein, a composite SPE has been fabricated by the cooperation of polyethylene oxide (PEO) and a type of natural nanoclay-halloysite nanotube (HNT) in a poly(vinylidene fluoride) (PVDF) matrix. It is expected that the sticky PEO can improve the interfacial stability of the SPE and lithium foil, while the special structure and surface charge properties of the HNTs changed the coordination environment of lithium ions and facilitated Li+ running on highways along the HNT outer surface. The optimized SPE composite showed an outstanding room-temperature ionic conductivity of 2.45 × 10–4 S cm–1 and high ion transference number of 0.67 at 25 °C. A LiFePO4/SPE-H5/Li full battery retained a discharge capacity of 142 mAh g–1 after 200 cycles at a rate of 0.2 C (25 °C). In addition, SPE-H5 can also be used in a 4.3 V high voltage NCM/SPE-H5/Li battery due to its excellent electrochemical stability window (more than 5 V). This work also reveals that lower-cost natural clay minerals are excellent nanoceramic fillers in realizing sustainable high-energy-density energy storage.