Solid Gel Electrolyte Research Articles

Nanorod-based smart windows with solid-gel electrolyte: An integrated electrochromic and pseudocapacitive technology for energy-saving and conversion

We fabricated two emerging nanorod-based smart windows with WO3 and NiO nanorods grown on the ITO/glass and ITO/muscovite mica (MM) substrates, respectively. The WO3/ITO/glass and WO3/ITO/MM substrates are excellent working electrodes, while the NiO/ITO/glass and NiO/ITO/MM substrates are exceptional counter electrodes. The nanorod-based WO3/Li+(s)/NiO@glass smart window consists of a WO3/ITO/glass working electrode, a NiO/ITO/glass counter electrode, and a solid-gel LiClO4 electrolyte (labeled as Li+(s)), respectively. The other nanorod-based WO3/Li+(s)/NiO@MM is comprised of a WO3/ITO/MM working electrode, a NiO/ITO/MM counter electrode, and a solid-gel LiClO4 electrolyte, respectively. Both the nanorod-based WO3/Li+(s)/NiO@glass and WO3/Li+(s)/NiO@MM smart windows have brilliant dual-band (red and near-infrared lights) electrochromic behaviors, such as large transmittance differences (ΔT), fast response times (bleaching time, tb, and coloration time, tc) at red (680nm) and near infrared (1000nm) lights and great electrochromic retention (4,000 cycles), and outstanding pseudocapacitive performances like good specific capacitances of ~18.4F/g and ~7.6F/g, intensive power densities of ~1779W/kg and ~2100W/kg with corresponding energy densities of ~5.4Wh/kg and ~2.2Wh/kg, enormous pseudocapacitive retention (10,000 cycles), and so on. Therefore, the brilliant dual-band electrochromic behaviors and outstanding pseudocapacitive performances make the nanorod-based WO3/Li+(s)/NiO@glass and WO3/Li+(s)/NiO@MM smart windows tremendous for use in multifunctional energy-saving-conversion devices.

“Seaweed Structure” design for solid gel electrolyte with hydroxide ion conductivity enabling flexible zinc air batteries

The construction of solid-state electrolytes for flexible zinc-air batteries is extremely challenging. A flexible and highly conductive solid electrolyte designed with a “seaweed structure” is reported in this work. Sodium alginate serves as the backbone to form a robust network structure, and the grafted quaternary ammonium groups provide channels for rapid ion transport, achieving excellent flexibility and hydroxide conductivity. The conductivity of the modified electrolyte membrane (QASA) is 5.23 × 10−2 S cm−1 at room temperature and reaches up to 8.51 × 10−2 S cm−1 at 75 °C. In the QASA based battery, bending at any angle is realized, and the power density is up to 57.28 mW cm−2. This work provides a new way to prepare high conductivity, green solid-state zinc-air batteries, and opens up a research line of thought for flexible energy storage materials.

Fabrication of CNT-N@Manganese Oxide Hybrid Nanomaterials through a Versatile One-Pot Eco-Friendly Route toward Engineered Textile Supercapacitors.

The expansion of the Internet of Things market and the proliferation of wearable technologies have generated a significant demand for textile-based energy storage systems. This work reports the engineered design of hybrid electrode nanomaterials of N-doped carbon nanotubes (CNT-N) functionalized with two types of manganese oxides (MOs)-birnessite (MnO2) and hausmannite (Mn3O4)-and their application in solid-state textile-based hybrid supercapacitors (SCs). A versatile citric acid-mediated eco-friendly one-pot aqueous precipitation process is proposed for the fabrication of the hybrids. Remarkably, different types of MOs were obtained by simply changing the reaction temperature from room temperature to 100 °C, without any post-thermal treatment. Asymmetric textile SCs were developed using cotton fabrics coated with CNT-N and the hybrids as textile electrodes, and poly(vinyl) alcohol/orthophosphoric acid as the solid-gel electrolyte. The asymmetric devices presented enhanced energy storage performance relative to the symmetric device based on CNT-N and excellent cycling stability (>96%) after 8000 charge/discharge cycles owing to synergistic effects between CNT-N and the MOs, which endowed nonfaradaic and pseudocapacitive features to the SCs. The asymmetric SC based on CNT-N@MnO2 featured 47% higher energy density and comparable power density to the symmetric CNT-N-based device (8.70 W h cm-2 at 309.01 μW cm-2 vs. 5.93 W h cm-2 at 346.58 μW cm-2). The engineered hybrid CNT-N@MO nanomaterials and the eco-friendly citric acid-assisted one-pot precipitation route open promising prospects not only for energy storage, but also for (photo)(electro)catalysis, wastewater treatment, and (bio)sensing.

Plastic turned into MXene–based pyro-piezoelectric hybrid nanogenerator-driven self-powered wearable symmetric supercapacitor

Today, the world is facing two major issues. First, there isa lack of available energy resources (conventional ones) to fulfill our energy requirements, and second, non-biodegradable plastic wastes spread over our planet, destroying its natural habitat. To provide a simplified solution to these problems, the authors of this work proposed a facile approach to convert plastic into titanium carbide–MXene (TiC–Ti3C2O2)–based pyro-piezoelectric hybrid nanogenerator driven wearable self-powered symmetric supercapacitor (SPSSC). NiSnO3–PVA–KOH and FeSnO3–PVA–KOH have been used as solid gel electrolytes, and their combined pyro-piezoelectric effect gives rise to the self-charging of the device. Moreover, the self-charging potential has been explored by incorporating normal forces, angular bending, heating, and increasing the device area. A maximum of 700 mV open-circuit voltage has been recorded. The specific capacitance of the SPSSC is 556 F g−1, an energy density of 111.11 W h kg−1 at a high-power density of 4 kW kg−1, and excellent cyclic stability of 93% after 10,000 repeated GCD cycles.

Solid Gel Electrolytes with Highly Concentrated Liquid Electrolyte in Polymer Networks and Their Physical and Electrochemical Properties and Application to Sodium Secondary Batteries

Gel polymer electrolytes consisting of sulfolane (SL)-NaN(SO2CF3)2 liquid electrolyte and a polyether-based host polymer were prepared, and their physicochemical and electrochemical properties were investigated. The prepared gel electrolytes generally exhibited high thermal stability regardless of the NaN(SO2CF3)2 concentrations. The glass transition temperature decreased with the NaN(SO2CF3)2 concentration owing to the strong interaction between SL and Na+. The ionic conductivities of all gel polymer electrolytes were higher than 10−4 S cm−1 at 303.15 K as a result of the plasticizer effect of SL. Although a relatively large interfacial resistance of the electrolyte/Na metal electrode was observed owing to the high reactivity of the SL-NaN(SO2CF3)2 electrolyte, the fabricated [Na metal negative electrode∣gel polymer electrolyte∣sulfur-modified polyacrylonitrile positive electrode] cell, i.e., the Na-S battery, achieved reversible charge-discharge operation at 333 K and demonstrated its potential to serve as an electric power storage system capable of low-temperature operation.

Immobilizing Ceramic Electrolyte Particles into a Gel Matrix Formed In Situ for Stable Li-Metal Batteries.

Hybrid solid/gel electrolytes (SGEs) have generated much research attentions because of their capability to suppress Li dendrite growth and improve battery safety. However, the interfacial compatibility of the electrode/electrolyte or polymer/inorganic ceramics within hybrid electrolytes remains challenging for practical applications. Herein, an SGE is fabricated by confining ceramic particles (Li7La3Zr2O12; LLZO) into in situ formed tetraethylene glycol dimethyl ether (G4)-based gel electrolytes within assembled cells. A hierarchical layered structure is formed when LLZO settles near the Li anode within the liquid electrolyte during the gradual gelatinization process. Good interfacial compatibility is obtained from good contact with the liquid G4 component. The LLZO layer also serves as an ionic sieve to redistribute the Li deposition. This SGE endows stable Li stripping/plating cycling over 800 h at 0.5 mA/cm2 (60 °C). Moreover, Li-metal batteries with an SGE coupled with LiFePO4 and an air cathode both exhibit superior cycling performance. This work presents a promising strategy for hierarchically layered SGEs for high-performance Li-metal batteries.

Smart dual-functional energy storage/fluorescent textile device based on a new redox-active Mn-doped ZnS solid-gel electrolyte

The evolution of wearable technologies boosted the development of energy storage textiles that can be charged faster and store energy for longer time. Achieving multifunctionality on textiles is a key milestone towards higher value-added smart products.Herein, we report on the fabrication of a novel dual-functional textile device merging enhanced energy storage performance with optical properties. A redox-active solid-gel electrolyte based on fluorescent manganese(II)-doped zinc(II) sulfide was for the first time used to endow the dual functionality to the device when combined with MWCNT-coated textile electrodes. The textile electrodes were prepared through an eco-sustainable straightforward dip-pad-dry process using a natural cotton fabric substrate.The fluorescent hybrid textile supercapacitor exhibited enhanced energy storage performance relative to the EDLC-type analogue containing the undoped electrolyte, namely 20% higher working voltage (1.64 V), 48% higher energy density (1.63 W h kg−1) and 74% higher power density (641.6 W kg−1). Additionally, it presented excellent cycling stability (100%) after 8000 charge/discharge cycles. The device exhibited intense yellow-orange fluorescence under UV light, while preserving the energy storage functionality. This work demonstrated the versatility of this type of devices for dark environment applications, namely in reflective/safety electronic clothing for nighttime users.

Flexible asymmetric solid-state supercapacitor of boron doped reduced graphene for high energy density and power density in energy storage device

Environment safe, cost-effective, reusable and portable asymmetric solid-state supercapacitor (ASSC) device, working at higher operating potential with high energy density was the challenging criteria for practical application. To satisfy all these we fabricated the ASSC device with boron doped reduced graphene (BRG) as positive and reduced graphene oxide as negative electrode with H2SO4/PVA solid gel electrolyte. Using three different precursors at different weight ratio of boric acid (HBG), boron powder (BG) and boron trioxide (BTG) boron doped reduced graphene oxide was prepared by hydrothermal treatment followed by pyrolysis at 1000 °C in CVD for 2 h. All electrode material exhibits a EDLC and pseudocapacitance in CV and GCD with high capacitance, HBG exhibits 225 Fg−1, BG shows 216 Fg−1 and BTG exhibits 266 Fg−1. Our BTG2//rGO ASSC device exhibits the specific capacitance of 122 Fg−1 with an energy density of 67.8 Wh Kg−1, also exerts an excellent stability of 94% capacitance retention with 99% of coulombic efficiency even after 5000 cycles. Using the device 5 mm red light emitting diode (LED) and DC motors was demonstrated for potential applications.

Exploring the impact of MoS2 on the performance of the planar solid micro-supercapacitor

A symmetric micro-supercapacitor (MSC) is constructed by electrochemically co-depositing molybdenum disulfide nanoflakes and poly-naphthalenemethylamine onto micro-patterned (100 μm track/gap) palladium current collectors over a plastic substrate. Within this structure, the polymer/MoS2 nanocomposite provides the percolating framework necessary to facilitate the charge transport and intercalation of ions through the entire electrode volume and functional chemical groups and/or defects, increasing the pseudocapacitance contribution. The hybrid MSC gave a high volumetric capacitance of 130 mF/cm3 at a scan rate of 5 mV/s, affording a 3.1 V potential window using a PVA-H2SO4 solid gel electrolyte. Overall, the strategy developed in this work on commercial interdigitated electrodes is based on an easily scalable technology, and further fine-tuning of the electrode design or active material volume can lead to supplementary improvement of the MSC's performance and cycling stability.

Fabrication and electrochemical properties of flexible ZnO doped PVA-Borax based solid-gel electrolytes

The flexible solid electrolytes are important for flexible batteries and supercapacitors. For that reason, we fabricated ZnO doped PVA-Borax based solid-gel electrolytes for 5%, 10% and 15% ZnO amounts in this study by chemical composition. The obtained ZnO doped PVA-Borax electrolytes were characterized by cyclic voltammetry (CV) measurements for 100, 200 and 400 mV scanning speeds and Raman spectroscopy. Furthermore, the two-electrode method was employed to determine the capacitance within the range of 0–1 V by 400 mV per second constant scan speed and then capacitance values of samples were calculated. Raman spectroscopy of the samples confirmed the ZnO doping in the PVA-Borax matrix. The obtained CV results revealed that the electrolytes exhibited rectangular shape due to its supercapacitor behavior. Also, the ZnO doping positively affected the supercapacitor behaviors. The results highlighted that the fabricated electrolytes can be improved for supercapacitor applications.

Single-pot hydrothermal synthesis of manganese phosphate microrods as a cathode material for highly stable flexible solid-state symmetric supercapacitors

Here, we report a binder-free synthesis of microrods-like manganese phosphate thin film over stainless steel substrate by a facile, single-pot hydrothermal method. The XRD analysis reveals that, the formation of manganese phosphate [Mn3(PO4)2] material of a monoclinic crystal structure. From SEM images observed microrods like morphology of manganese phosphate with an average width of ∼25 μm. The manganese phosphate electrode shows a better electrochemical performance with a specific capacitance of 145 F g−1 at 0.2 mA cm-2 current density in 1.0 M Na2SO4 electrolyte. Moreover, the flexible solid-state symmetric electrochemical energy storage device was assembled with PVA-Na2SO4 solid gel-electrolyte consists of manganese phosphate as anode and cathode electrode. The corresponding symmetric supercapacitor achieves a high energy density of 11.7 Wh kg−1 at a high power density of 1.41 kW kg−1 with an excellent specific capacitance of 37 F g−1 at 0.1 mA cm-2 current density. Manganese phosphate shows long-term electrochemical cyclic stability at a current density of 0.8 mA cm-2 for 9000 galvanostatic charge-discharge cycles with excellent capacitance retention (99 %). This excellent capacitive performance confirms that the manganese phosphate is promising material and fabricated flexible solid-state symmetric supercapacitor has high potential in the field of portable and bendable energy storage devices.

Thermal regulation of satellites using adaptive polymeric materials

This paper focuses on the thermal performances of an adaptive radiator made of 16 electroemissive devices (EEDs) acting as electro-active materials for thermal control of satellites. EEDs are similar to an electrochemical cell where one electrode serves as active layer in the infrared and is made of a conducting polymer, the poly(3,4-ethylenedioxythiophene) (PEDOT), interpenetrated into a polyethylene oxide/nitrile butadiene rubber (PEO/NBR) solid gel electrolyte as supporting matrix. First, EEDs were placed in moderate vacuum (10-3 bars) to estimate their optical cyclability c.a. 4000 cycles in neutral and oxidized state. Then, an electro-emissive radiator (EER) assembled with 16 EEDs (total area of 80cm2) was tested under space vacuum conditions. “Hot” and “cold” operating cases of the satellite were simulated and ability of the radiator to control radiative exchanges between the satellite and its environment was estimated by comparison with the currently used optical solar reflector (OSR) radiators. In low emissivity state, the EER can slow down the rejection of heat in a cold environment which is an interesting feature in terms of energy saving. Also when the EER is not directly exposed to the sun, it is able to reject the heat in the same way as the OSR radiator in a hot phase. By comparing the electrical consumption with a system operating with OSR, an energy saving in the order of 25% was demonstrated. Finally the EER exhibits bistability during many hours, i.e. memory effect once electrically switched into a given emissivity state, allowing to further reduce the electrical consumption.

Highly Concentrated Aqueous Gel Electrolytes for Diverse Battery Applications

The development of aqueous solutions containing comparatively high amounts of dissolved salts has brought water, an unlikely solvent, into the ongoing development of new battery chemistries. Aqueous electrolytes have the advantage of being inherently non-flammable materials, while demonstrating high cation transference number behavior and cation conductivity in the range of 1-10 mS/cm2 in the case of Li+. As a reaction medium, highly concentrated aqueous electrolytes allow for polymerization reactions such as radical polymerization to occur, and it has been demonstrated that the kinetics of these reactions are fast enough to allow rapid processing into films of solid gel electrolytes. While lithium ion batteries were one of the first applications of aqueous gel electrolytes, we have synthesized gel electrolytes for the increasingly popular sodium and zinc systems as well. This talk will focus on the kinetics of polymerization of various radicalized monomers, the formation and properties of the solid gels that result, and the electrochemical behavior and application tree that follow using the new electrolyte materials.

High-Performance Double-Network Ion Gels with Fast Thermal Healing Capability via Dynamic Covalent Bonds

A tough double-network (DN) ion gel composed of chemically cross-linked poly(furfuryl methacrylate-co-methyl methacrylate) (P(FMA-co-MMA)) and physically cross-linked poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-co-HFP)) networks with 80 wt % of ionic liquid (IL) was fabricated via a one-pot method. This ion gel exhibits excellent mechanical strength and considerable ionic conductivity, which can be used as a solid gel electrolyte. Upon an adjustment of the weight ratio of P(FMA-co-MMA) to P(VDF-co-HFP) and the content of the cross-linker, remarkably robust DN ion gel (failure tensile stress 660 kPa, strain 268%; failure compressive stress 17 MPa, strain 85%) was obtained. The high mechanical strength is attributed to the chemical/physical interpenetrating networks. The rigid chemically cross-linked P(FMA-co-MMA) network dissipates most of the loading energy, and the ductile physically cross-linked P(VDF-co-HFP) network provides stretchability for the whole gel. More importantly, the P(FMA-co-M...

Metal Precursor Dependent Synthesis of NiFe2O4 Thin Films for High-Performance Flexible Symmetric Supercapacitor

Herein, we report the chemical synthesis of NiFe2O4 thin films forming nanosheet-, nanoflower-, and nanofeather-like morphologies using NiCl2·6H2O, Ni(NO3)2·6H2O, and NiSO4·6H2O nickel salt precursors, respectively, while using the same iron salt precursor. A nanostructure formation mechanism is proposed in detail using coordination chemistry theory. Interestingly, nanostructures of NiFe2O4 nanosheets revealed a maximum surface area of 47 m2 g–1, which was higher than those of nanoflowers and nanofeathers (25 and 11 m2 g–1). Similarly, the supercapacitive properties of the individual NiFe2O4 nanosheet-based electrode demonstrated maximum specific capacitance of 1139 F g–1, which is found to be better than that of NiFe2O4 nanoflowers (677 F g–1) and nanofeathers (435 F g–1) in 6 M KOH electrolyte. Furthermore, the symmetric device fabricated using NiFe2O4 nanosheet electrodes and PVA-KOH solid gel electrolyte shows higher specific capacitance of 236 F g–1 with 98% retention after 7000 cycles and higher spe...

Carbon Nanotubes on Highly Interconnected Carbonized Cotton for Flexible and Light‐Weight Energy Storage

Development of novel light‐weight materials with high areal/volumetric energy density using bioresources provides a sustainable solution for portable energy storage devices. Most of the existing materials are powders or disordered textures with marginal interconnectivity among micro‐/mesoporous structures, leading to a low specific capacitance per geometric area and higher internal resistance as electrode materials. This work describes a simple strategy to develop carbon nanotubes on highly interconnected fibers in a carbonized cotton cloth using a single‐step chemical vapor deposition method. The developed material shows hierarchical structures with low weight (0.27 g cm−3), high surface area (137 m2 g−1), and excellent electrical conductivity (3.0 S cm−1). When employing the developed material as electrodes for aqueous and solid–gel electrolyte based supercapacitors, the sample exhibits specific areal capacitances of 1286 mF cm−2 (at 1 mA cm−2 current density) and 1140 mF cm−2 (at 2.5 mA cm−2 current density), respectively, which are much higher than recently reported carbon‐based electrode materials. The superior capacitance and high flexibility of fibrous carbon cloth endow the material great potential for light‐weight energy storage applications.

Solid gellan gum polymer electrolyte for energy application

In this paper a carbohydrate polymer (Phytagel/gellan gum) based solid gel electrolyte synthesis and its application in dye sensitized solar cell is reported. Potassium iodide has been added in Gelrite/Phytagel biopolymer matrix to develop solid gel electrolyte. Complex impedance spectroscopy shows liquid like ionic conductivity, with maximum conductivity 2.5 × 10−2 S cm−1 at 60:40 composition. Infrared spectroscopy (IR) confirms the formation of complex nature while x-ray diffraction (XRD) affirms the composite nature and suppression in crystallinity by salt doping. Polarized microscopy (POM) shows enhancement in amorphousity of gel matrix by salt doping which is a known favourable condition for ionic conductivity enhancement in gel electrolyte system and supported by our XRD data. A dye sensitized solar cell (DSSC) has been fabricated using maximum conductivity which shows with Jsc = 3.2 × 10−3 mA/cm2, Voc = 0.57, FF = 0.90, ɳ = 1.47 at 1 sun condition.

An efficient quasi solid state dye sensitized solar cell based on polyethylene glycol/graphene nanosheet gel electrolytes

A poly(ethylene glycol)/graphene nanosheet quasi solid gel electrolyte was synthesized using an in situ polymerization technique for dye-sensitized solar cells (DSSCs).

Cost-effective dye-sensitized solar cells based on commercial nanocrystalline titania and a ureasil gel electrolyte

Nanocomposite organic-inorganic dye-sensitised solar cells have been constructed by using solution processed materials that are easily deposited, they do not necessitate sealing or encapsulation and offer satisfactory efficiency. The main components of the cell are a nanocrystalline titania layer made of commercial Degussa P25 and a solid gel electrolyte made of a ureasil precursor. Details on cell construction are given and show that the whole procedure can be upscaled for massive production.

Nano-sponge ionic liquid–polymer composite electrolytes for solid-state lithium power sources

Solid polymer gel electrolytes composed of 75 wt.% of the ionic liquid, 1- n-butyl-2,3-dimethylimidazolium bis-trifluoromethanesulfonylimide with 1.0 M lithium bis-trifluoromethanesulfonylimide and 25 wt.% poly(vinylidenedifluoro-hexafluoropropene) are characterized as the electrolyte/separator in solid-state lithium batteries. The ionic conductivity of these gels ranges from 1.5 to 2.0 mS cm −1, which is several orders of magnitude more conductive than any of the more commonly used solid polymers, and comparable to the best solid gel electrolytes currently used in industry. TGA indicates that these polymer gel electrolytes are thermally stable to over 280 °C, and do not begin to thermally decompose until over 300 °C; exhibiting a significant advancement in the safety of lithium batteries. Atomic force microscopy images of these solid thin films indicate that these polymer gel electrolytes have the structure of nano-sponges, with a sub-micron pore size. For these thin film batteries, 150 charge–discharge cycles are run for Li x CoO 2 where x is cycled between 0.95 down to 0.55. Minimal internal resistance effects are observed over the charging cycles, indicating the high ionic conductivity of the ionic liquid solid polymer gel electrolyte. The overall cell efficiency is approximately 98%, and no significant loss in battery efficiency is observed over the 150 cycles.