水溶性Janus型POSS的设计合成及其对PAA/PAM水凝胶力学性能影响的研究

利用丙烯酰氧丙基多面体低聚倍半硅氧烷（Acrylo-POSS）和3-巯基-1-丙烷磺酸盐（MPS）之间的巯基点击反应，一步合成水溶性Janus型多面体低聚倍半硅氧烷（AS-POSS）。通过改变投料比可以调控AS-POSS的水溶性和双键与磺酸钠基团的物质的量比。将AS-POSS与丙烯酸（AA）和丙烯酰胺（AM）共聚制备了一系列不同AS-POSS含量的AS-POSS/PAA/PAM水凝胶，其中AS-POSS质量占单体总质量1%的1% AS-POSS/PAA/PAM水凝胶的平衡溶胀比达到512，断裂伸长率达到1074%，压缩强度为583 kPa，压缩应变为89%，屈服应变为330%，均大于对照组MBA/PAA/PAM水凝胶，表明AS-POSS的引入显著提高了水凝胶的溶胀度，明显增强了水凝胶的韧性、抗压缩性能和动态力学性能。AS-POSS/PAA/PAM水凝胶具有良好的导电性，离子电导率最高可达0.401 S/m。     

Reversibly highly stretchable and self-healable zwitterion-containing polyelectrolyte hydrogel with high ionic conductivity for high-performance flexible and cold-resistant supercapacitor

It remains challenging to develop stretchable and self-healable polymer electrolytes with improved ion-conductive nature for high-performance multifunctional flexible supercapacitors. Herein, a P(AM-SBMA-AMPS)-SiO₂ zwitterion-containing polyelectrolyte hydrogel is fabricated via copolymerization of acrylamide (AM), sulfobetaine methacrylate (SBMA) zwitterionic monomer, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) anionic monomer grafted from the surface of vinyl silica nanoparticles (VSNPs). The hydrogen bonding among polymer chains and the high-density dynamic ionic interactions between SBMA and AMPS work as reversible “sacrificial bonds” to toughen hydrogel, while the VSNPs function as multifunctional crosslinkers and stress transfer centers, which makes these hydrogels tough (fracture energy 2.7 MJ m⁻³), stretchable (fracture strain 4,016%), and self-healable (fracture strain of healable sample 775%). More importantly, this zwitterion-containing polyelectrolyte hydrogel exhibits high ionic conductivities (3.4 S m⁻¹) owing to the highly hydration capacity of the zwitterionic polyelectrolyte copolymer which produced efficient ion migration channels for ion transport. Accordingly, a flexible supercapacitor based on this multifunctional hydrogel as electrolyte demonstrates a high electric double-layer capacitive capacitance of 60.6 F g⁻¹ at 0.5 A g⁻¹ and excellent capacitance retention of ~98% over 1,000 cycles as well as encouraging electrochemical properties at subzero temperature. This work provides new insights into the synthesis of highly conductive and multifunctional polyelectrolyte hydrogels for high-performance flexible supercapacitors. © 2020 Wiley Periodicals, Inc.     

抗冻水凝胶的制备及其在柔性电子领域的应用

水凝胶具有优异的柔韧性、离子运输性和可调的机械性,在柔性电子领域具有广阔的应用前景,然而,水凝胶电子器件在严寒气候下容易冻结失效,严重限制了其在低温环境下的应用潜力,通过向水凝胶中引入低温防护剂可以赋予水凝胶抗冻性能,拓宽水凝胶电子器件的工作温度。该文从溶质离子、离子液体、有机溶剂以及抗冻蛋白改性水凝胶4个方面,综述了近年来抗冻水凝胶的制备方法和抗冻机理,阐述了抗冻水凝胶在超级电容器、传感器和电池等柔性电子领域的应用进展,归纳了抗冻水凝胶电子材料面临的问题与挑战,并展望了抗冻水凝胶电子材料的发展趋势,指出以天然可再生资源为原料开发具有优异机械性能、电化学性能、生物无毒性、生物相容性和生物可降解的抗冻水凝胶成为下一步研究重点,同时设计优化柔性电子装置、提高器件安全可靠性和输出稳定性也将成为重要的研究方向之一。抗冻水凝胶的制备及其应用研究将促进柔性电子功能材料领域的快速发展。     

Influence of chromium content on microstructural and electrochemical supercapacitive properties of vanadium nitride thin films developed by reactive magnetron co-sputtering process

Two-dimensional nanostructured transition metal nitride-based thin film electrodes have been gaining importance in the electrochemical supercapacitor applications. In this work, Cr doped vanadium nitride (VN) thin films as an electrode material for high-performance supercapacitors have been demonstrated. In this study, reactive magnetron co-sputtering technique was adopted to fabricate phase pure VN as well as VN films doped with different Cr contents. These films were directly investigated as electrodes without using any additional binders. The phase purity and the surface chemistry of the Cr doped VN thin films were investigated using XRD and XPS techniques. Furthermore, EDS and X-ray elemental mappings were used to confirm the content of Cr and its distribution in these electrode films. The Cr −5.7 at. % doped VN thin film electrodes exhibited an extraordinary supercapacitor performance with the maximum areal capacitance of 190 mF/cm² compared to the areal capacitance of 27 mF/cm² for the un-doped VN at a scan rate of 10 mV/s. Moreover, the Cr-5.7 at. % doped VN thin film electrodes showed excellent electrochemical cycling stability and excellent reversibility with the capacitance retention of 92.4 %. It could be noticed that the incorporation of metal such as Cr could be a viable method to improve the electronic or ionic conductivity of the metal nitrides for supercapacitor applications.     

Quickly self-healing hydrogel at room temperature with high conductivity synthesized through simple free radical polymerization

The use of conductive self-healing hydrogels in electronic devices not only reduces replacement and maintenance costs but also prolongs their lifetime. Therefore, developing hydrogels with autonomous self-healing properties and electronic conductivity is vital for the advancement of emerging fields, such as conductors, semiconductors, sensors, artificial skin, and electrodes and solar cells. However, it remains a challenge to fabricate a hydrogel with high conductivity that can be healed quickly at room temperature without any external stimulus. In this work, we report an effective and simple free radical polymerization approach to synthesizing a hydrogel using modified rGO and acrylate monomers containing abundant ion groups. The hydrogel exhibits excellent electronic conductivity, extremely fast electronic self-healing ability, and excellent repeatable restoration performance at 25 °C. The conductivity of the hydrogel reaches 27.2 S/m, the hydrogel recovers its original shape, and scoring scratched on the surface totally disappears after holding at 25 °C for 40 s. This conductive, room-temperature self-healing hydrogel takes unique advantage of supramolecular chemistry and polymer nanoscience and has potential applications in various fields such as self-healing electronics, artificial skin, soft robotics, biomimetic prostheses, and energy storage. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47379.     

Dual Cross-Linked Polymethacrylic Acid Hydrogels with Tunable Mechanical Properties and Shape Memory Behavior

Herein, a series of poly(methacrylic acid) hydrogels are prepared via bulk polymerization of methacrylic acid (MAAc) and grafting of Triton X-100 (TX-100). One-pot and extremely simple chemistry consist of only mixing and subsequently heating of commercially available monomer and surfactant. The polymer chains are interconnected through dual physical cross-link points formed by the hydrophobic associations in the center of TX-100 micelles and hydrogen bonds stabilized by hydrophobic α-methyl groups of MAAc. The hydrogels exhibit tunable mechanical properties ranging between softness and stiffness by adjusting the surfactant/monomer molar ratio, such as Young modulus of 0.6−22 MPa, elongation at break of 750−1700%, tensile strength of 0.21−3.6 MPa, and compressive strength of 41−93 MPa. The synergistic effect of high-density hydrogen bonds with hydrophobic associations endows a plastic-like hydrogel with high strength and shape memory (SM) behavior, while a high concentration of micelles with low-density hydrogen bonds endows a stretchable elastic hydrogel. The combination of temperature-induced SM property and wide-ranging mechanical performance will make such hydrogels useful in diverse applications.     

A redox‐mediator‐doped gel polymer electrolyte applied in quasi‐solid‐state supercapacitors

Methylene blue (MB) redox mediator was introduced into polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) blend host to prepare a gel polymer electrolyte (PVA‐PVP‐H₂SO₄‐MB) for a quasi‐solid‐state supercapacitor. The electrochemical properties of the supercapacitor with the prepared gel polymer electrolyte were evaluated by cyclic voltammetry, galvanostatic charge–discharge, electrochemical impedance spectroscopy, and self‐discharge measurements. With the addition of MB mediator, the ionic conductivity of gel polymer electrolyte increased by 56% up to 36.3 mS·cm^?1, and the series resistance reduced, because of the more efficient ionic conduction and higher charge transfer rate, respectively. The electrode specific capacitance of the supercapacitor with PVA‐PVP‐H₂SO₄‐MB electrolyte is 328 F·g^?1, increasing by 164% compared to that of MB‐undoped system at the same current density of 1 A·g^?1. Meanwhile, the energy density of the supercapacitor increases from 3.2 to 10.3 Wh·kg^?1. The quasi‐solid‐state supercapacitor showed excellent cyclability over 2000 charge/discharge cycles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39784.     

纳米SiO2填料对离子凝胶电解质及高压超级电容器性能的影响

以SiO2纳米颗粒为填料,通过溶液浇筑法合成了纳米复合离子凝胶电解质,研究了SiO2填料对离子输运的影响规律。基于离子凝胶电解质构筑了准固态电容器,探讨了无机填料对电容器性能的影响,以活性炭为电极、凝胶电解质为隔膜,构筑了准固态双电层电容器。结果表明,SiO2的加入没有改变隔膜电解质的微观形貌,但有效改善了浸润性,提高了离子电导率。高SiO2添加量的隔膜电解质电化学性能更优,当添加8wt% SiO2时凝胶电解质电化学性能最优。SiO2的加入可有效提高活性炭准固态电容器的性能,电容器的比容提升约15%,经4000次循环后容量保持可达100%。电解质高温稳定性良好,器件最高使用温度可达60℃。基于该复合电解质构筑的电容器具有良好的高温性能,电容器比容随温度升高而逐渐提升,60℃时能量密度可达81.36 Wh/kg。     

硅酸盐水泥基复合电解质的制备及其在建筑储能器件中的应用

近几年,将水泥基复合材料用于建筑储能已成为研究热点之一。本文将硅酸盐水泥、丙烯酰胺(AM)混合制备了一种优化的水泥基复合结构电解质,并研究了AM质量分数分别为0%、25.0%、27.5%、30.0%、32.5%和35.0%时对结构电解质的离子电导率、力学性能及微观结构的影响。研究结果表明,增加AM的掺量有助于提高硅酸盐水泥基复合电解质的离子电导率,同时会不可避免地降低电解质的抗压强度。当AM掺量为30.0%时,可以使离子电导率和抗压强度达到理想平衡,抗压强度高达41.1 MPa,离子电导率最大为22.47 mS·cm^-1。此外,对结构电解质与还原氧化石墨烯(rGO)电极组装成一体式的结构超级电容器进行了一系列电化学性能测试,发现AM掺量为30.0%的硅酸盐水泥基复合电解质构成的结构超级电容器的面积比电容最大可以达到96.8 mF·cm^-2。在恒定电流为0.1 mA·cm^-2下充放电循环5 000次后,该结构超级电容器的面积比电容值保持率为91.08%,该结构超级电容器在建筑储能领域具有广阔的应用前景。     

离子液体型超级电容器软包高温老化性能评测研究

构筑了介孔炭,离子液体（EMIMBF₄）与泡沫铝极片结构的超级电容器软包（容量为40 F）,评测了其在2.7 V,65℃,1500 h老化实验中的性能。利用恒流充放电、恒流-恒压充放电模式评测,该电容器经过连续1500 h的高温处理后电容值衰减约10%,内阻增加比例低于40%。与传统的乙腈基电解液软包对比,虽然乙腈基软包起始内阻低,但产气多,且高温循环条件下容量衰减比例和内阻增加比例均劣于离子液体基电解液。上述对比说明,离子液体基电解液在泡沫铝三维导电导热结构的配合下,具有了良好的长周期循环性能。同时,由于其无毒性,可以用于封闭的楼宇空间或其他场所,提供本质安全性。     

Crosslinked quaternized poly(arylene ether sulfone) copolymer membrane applied in an electric double-layer capacitor for high energy density

The low energy density of supercapacitors, especially supercapacitors based on aqueous electrolytes, is the main factor limiting their application, and the energy density is closely related to the operating potential window of the supercapacitor. The polymer electrolyte is the main contributor to the safe operation and good ion conductivity of the supercapacitor. In this study, a crosslinked quaternized poly(arylene ether sulfone) (PAES) membrane was prepared via crosslinking during membrane formation with a thermal-only treatment and applied in an electric double-layer capacitor (EDLC). The pre-prepared PAES membrane formed a polymer electrolyte with 1 mol/L Li₂SO₄ and was then fabricated into an EDLC single cell. The properties of both the membrane and ELDC were investigated. The preferred cPAES-N-0.2 polymer electrolyte showed an ionic conductivity of 1.18 mS/cm. The optimized EDLC exhibited a single-electrode gravimetric capacitance of 104.92 F/g at a current density of 1.0 A/g and a high operating potential window (1.5 V); it, thereby, achieved a high energy density of 8.20 W h/kg. The EDLC also exhibited excellent cycling properties over 3000 charge–discharge cycles. The crosslinked structures promoted the tensile strength and thermal stability of the PAES membranes; this was accompanied by a slight decrease in the ionic conductivity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47759.     

Synthesis of multifunctional high strength,highly swellable,stretchable and self‐healable pH‐responsive ionic double network hydrogels

The multifunctional double network (DN) soft hydrogels reported here are highly swellable and stretchable pH‐responsive smart hydrogel materials with sufficient strength and self‐healing properties. Such multifunctional hydrogels are achieved using double crosslinking structures with multiple physical and chemical crosslinks. They consist of a copolymer network of acrylamide (AM) and sodium acrylate (Na‐AA) and other reversible network of poly(vinyl alcohol)–borax complex. They were characterized by Fourier transform IR analysis and studied for their hydrogen bonding and ionic interaction. The degree of equilibrium swelling was observed to be as high as 5959% (at pH 7.0) for a hydrogel with AM/Na‐AA = 25/75 wt% in the network (GS‐6 sample). The highest degree of swelling was observed to be 6494% at pH 8.5. The maximum tensile strength was measured to be 1670, 580 and 130 kPa for a DN hydrogel (GS‐2 sample: AM/Na‐AA =75/25 wt% with 20, 40 and 60 wt% water content, respectively). The self‐healing efficiency was estimated to be 69% for such a hydrogel. These multifunctional DN hydrogels with amalgamation of many functional properties are unique in hydrogel materials and such materials may find applications in sensors, actuators, smart windows and biomedical applications. © 2018 Society of Chemical Industry     

Ultratough and recoverable ionogels based on multiple interpolymer hydrogen bonding as durable electrolytes for flexible solid-state supercapacitor

The emerging application of ionogels in flexible devices require it enough durable under repeated mechanical deformation while maintaining their superior electrochemical properties. In this work, ultratough and recoverable ionogels, where ionic liquids are confined in chemically and interpolymer hydrogen-bonding hybrid crosslinked network, were fabricated by in situ copolymerization of acrylic acid and 1-vinylimidazole monomer within 1-buty-3-methylimidazolium chloride ionic liquid. The reversible hydrogen bonds between imidazole and carboxylic acid groups of polymer chains in the network work as reversible “sacrificial bonds” to toughen ionogel, which makes the ionogels tough (tensile strength 1.62 MPa, toughness 8.7 MJ m⁻³), stretchable (elongation at break 1090%), and recoverable (91% recovery resting for 30 min, at 534 kPa stress and 500% strain). Moreover, the hydrogen-bonded ionogels exhibit high ionic conductivity of 2.3 S m⁻¹ at 80°C to 3.2 S m⁻¹ at 150°C. Furthermore, the ionogel-based flexible electrical double-layer capacitor can be operated up to 1.5 V with a capacitance of 341.47 F g⁻¹ at 0.5 A·g⁻¹ and exhibits excellent capacitance retention after 1000 cycles as well as superior electrochemical performance over a wide range of temperature. This work provides new insights into the synthesis of tough and recoverable ionogels for high-performance flexible supercapacitors.     

Gel Polymer Electrolyte with Anion‐Trapping Boron Moieties via One‐Step Synthesis for Symmetrical Supercapacitors

A novel gel polymer electrolyte (GPE) which is based on new synthesized boron‐containing monomer, benzyl methacrylate, 1 m LiClO₄/N,N‐dimethylformamidel liquid electrolyte solution is prepared through a one‐step synthesis method. The boron‐containing GPE (B‐GPE) not only displays excellent mechanical behavior, favorable thermal stability, but also exhibits an outstanding ionic conductivity of 2.33 mS cm^?1 at room temperature owing to the presence of anion‐trapping boron sites. The lithium ion transference in this gel polymer film at ambient temperature is 0.60. Furthermore, the symmetrical supercapacitor which is fabricated with B‐GPE as electrolyte and reduced graphene oxide as electrode demonstrates a broad potential window of 2.3 V. The specific capacitance of symmetrical B‐GPE supercapacitors retains 90% after 3000 charge–discharge cycles at current density of 1 A g^?1.     

Investigation of electrochemical behaviour of storage device prototypes with carbon electrodes

The electrochemical behavior of storage device prototypes with carbon electrodes and ionic liquids as electrolyte was investigated. The current-voltage dependences using different working electrodes and the dependences of specific capacitance, charge and discharge dynamics of supercapacitor cells on time were obtained. The optimal values of specific capacitance and specific energy of film-like supercapacitor samples at different voltages were obtained.     

Improvement of the performance for quasi-solid-state supercapacitor by using PVA–KOH–KI polymer gel electrolyte

A quasi-solid-state supercapacitor was assembled by using alkaline polyvinyl alcohol and potassium iodide (PVA–KOH–KI) as gel electrolyte and activated carbons electrodes. The electrocapacitive properties of the supercapacitor were evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. The introduction of KI increases the ionic conductivity of electrolyte, and improves the pseudocapacitance of the electrode. The specific capacitances of the supercapacitor is 236.90 F g⁻¹, increasing by 74.28% compared to the PVA–KOH system at the same current density. The energy density and power density of the supercapacitor reach 7.80 Wh kg⁻¹ and 15.34 kW kg⁻¹, respectively. In addition, the supercapacitor exhibits excellent cycle-life stability.     

Properties of biodegradable hydrogels prepared by γ irradiation of microbial poly(ϵ-lysine) aqueous solutions

Poly(?-lysine) (PL) hydrogels have been prepared by means of γ irradiation of PL produced by Streptomyces albulus in aqueous solutions. When the dosage of γ irradiation was 70 kGy or more and the concentration of PL in water was 1–7 wt %, transparent hydrogels (opaque hydrogels for 1–3 wt % PL concentration) could be produced. In the case of 70 kGy of γ irradiation and 5 wt % PL concentration, the specific water content (wt of absorbed water/wt of dry hydrogel) of the PL hydrogel was approximately 160. Specific water contents of PL hydrogels decreased markedly with an increase in the dosage of γ irradiation. The specific water contents were increased with an increase in PL concentration in the irradiated solution. This result indicates the presence of a radical scavenger in the PL solution. Swelling equilibria of PL hydrogels were measured in water or in aqueous solutions of various pHs or concentrations of NaCl, Na₂SO₄, and CaCl₂. Under acid conditions, the PL hydrogel swelled due to the ionic repulsion of the protonated amino groups in the PL molecules. The degree of deswelling in electrolyte solution was smaller than that of other ionic hydrogels [poly(γ-glutamic acid), poly(acrylic acid) etc.]. In addition, the enzymatic degradations of PL hydrogel were studied at 40°C and pH 7.0 in an aqueous solution of the neutral protease [Protease A (Amano)] produced from Aspergillus oryzae. The rate of enzymatic degradation of the respective PL hydrogels was much faster than the rate of simple hydrolytic degradation. The rate of enzymatic degradation decreased with the increase in γ-irradiation dose during preparation of the PL hydrogel. © 1995 John Wiley & Sons, Inc.     

All solid supercapacitor based on activated carbon and poly [2,5-benzimidazole] for high temperature application

In the present work, we report high temperature performance of solid electrolyte supercapacitor based on activated carbon (AC) and phosphoric acid doped poly [2,5 benzimidazole] (ABPBI). Supercapacitors with varying concentrations of solid electrolyte in the electrode were fabricated and unit cells were analyzed over a wide temperature range of 27–120 °C. Supercapacitor with AC/ABPBI wt ratio 1.0:0.25 exhibited a specific capacitance of 197 F g^?1 at room temperature. To the best of our knowledge, the value reported here is one of the highest for electric double layer supercapacitor with a solid electrolyte. The specific capacitance of supercapacitors having various compositions increased with temperature. The specific capacitance for AC/ABPBI wt ratio 1.0:0.25, capacitance increased to 248 F g^?1 at 120 °C. The performance of supercapacitors was also analyzed by electrochemical impedance spectroscopy. The Nyquist plots at room temperature and 100 °C were studied by fitting them using Randles equivalent circuit. Supercapacitor with AC/ABPBI wt ratio 1.0:0.25 showed phase angle of 86.8° at low frequency which indicated excellent capacitive behavior at room temperature. The supercapacitor was found to have good stability during galvanostatic charge–discharge cycling even after repeated heating and cooling.     

LiClO4 doped cellulose acetate as biodegradable polymer electrolyte for supercapacitors

The possibility of producing a biodegradable polymer electrolyte based on cellulose acetate (CA) with varied concentration of LiClO₄ for use in supercapacitors has been investigated. The successful doping of the CA films has been analyzed by FTIR and DSC measurements of the LiClO₄ doped CA films. The ionic conductivity of the films increased with increase in salt content and the maximum ionic conductivity obtained for the solid polymer electrolyte at room temperature was 4.9 × 10^?3 Ω^?1 for CA with 16% LiClO₄. The biodegradation of the solid polymer electrolyte films have been tested by soil burial, degradation in activated sludge, and degradation in buffer medium methods. The extent of biodegradation in the films has been measured by AC Impedance spectroscopy and weight loss calculations. The study indicated sufficient biodegradability of the materials. A p/p polypyrrole supercapacitor has been fabricated and its electrochemical characteristics and performance have been studied. The supercapacitor showed a fairly good specific capacitance of 90 F g^?1 and a time constant of 1 s. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Integration of MnO2 and ZIF-Derived nanoporous carbon on nickel foam as an electrode for high-performance supercapacitors

MnO₂ has the highest potential as a supercapacitor electrode; however, its disadvantage in electronic conductivity hinders its widespread use. This study reports the excellent electrochemical performance of MnMC/NF (MnO₂ and ZIF-derived nanoporous carbon on nickel foam) composites. MnMC/NF composites are produced when leaf-like Co-ZIF is annealed on nickel foam, followed by potassium permanganate treatment. When the annealing temperature reaches 700 °C, the maximum specific capacitance of 531 F/g is achieved at 1 A/g (456 F/g at 20 A/g) with a rate capability of 85.5%. MnMC/NF700 has a long cyclic stability, and the capacitance retention was 82% after 5000 cycles. The energy density of an assembled device using MnMC/NF700 composite as positive electrodes can reach 38.8 Wh/kg. This is due to the combined effect of nickel substrate's 3D porous structure and the excellent electronic conductivity of ZIF-derived nanoporous carbon. The unique configuration of MnMC/NF composites may provide a referable design for energy storage systems, including materials that have the highest potential for use as supercapacitor electrodes.