Ni (Nickel) doped zeolitic-imidazolate framework (ZIF-67) has been prepared in presence of reduced graphene oxide (rGO) to realize a ZIF-67/rGO composite. The doping level of Ni and the ratio of rGO ...(wt%) in the composite have been optimized to attain desirable redox activity and electrical conductivity. A partial incorporation of redox active Ni ions to substitute Co (cobalt) ions in ZIF-67 has resulted in better electrochemical characteristics by inducing additional pseudocapacitance. A finalized composite with 33% Ni and 20% of rGO (i.e, Ni33/ZIF-67/rGO20) has been used as a supercapacitor electrode material to achieve a high specific capacitance of 304 F/g at a current density of 1 A/g in the presence of 1 M H2SO4 as an aqueous electrolyte. The above electrode has also been tested for an all-solid-state symmetric supercapacitor in the presence of a polymer gel electrolyte (PVA/1 M H2SO4). This device delivered high values of power and energy densities, i.e., 1 kW/kg and 21.5 Wh/kg, respectively. The device also exhibited an excellent cyclic stability. About 87% of capacitance could be retained even after 4500 charge-discharge cycles. The device has shown superior results for a working potential window of 0–2 V. The practical usefulness of the device has been demonstrated by preparing a symmetrical supercapacitor, which could energize a white LED for 8 min upon a charging of only 40 s.
Display omitted
•High surface area and conductive composite of Ni doped ZIF-67/rGO is synthesized.•The as synthesized composite is studied for 2V symmetrical supercapacitor device.•Supercapacitor displays long cycle life of 87% after 4500 charge-discharge cycles.•High values of energy (21.5 W h/kg) and power (1 kW/kg) densities are obtained.
High-energy rechargeable lithium metal batteries have attracted soaring attention because of high specific capacity and low electrochemical potential of lithium metal. Unfortunately, the lithium ...dendrite growth upon Li plating severely hinders its practical application. Herein, we report the preparation of ionic liquid (IL) immobilized polymer gel electrolytes with strong ion-dipole interactions between imidazolium-based IL and fluorinated copolymer gel for stable and dendrite-free Li+ plating/stripping. The adoption of IL leads to the formation of a tightly cross-linked gel framework with tethered anions, providing greatly-improved mechanical strength, good heat resistance, favorable self-healing capability, high ionic conductivity, and a stable electrochemical window up to 4.5 V vs. Li+/Li that can satisfy the demand of high-voltage cathodes. The membrane of IL-immobilized polymer gel electrolyte enabled dendrite-free Li deposition, showing stable cycling durability for 1000 h at 0.5 mA cm−2, and the functional mechanism was carefully investigated. By coupling with this gel electrolyte membrane, the LiFePO4/Li cell exhibit much superior cycling stability and rate performance. Moreover, the lithium-sulfur batteries assembled with the IL-immobilized polymer gel electrolyte also show efficient suppression of polysulfide shuttling and self-discharge, bringing high specific capacity and long cycling life.
Display omitted
•The tightly cross-linked gel network with tethered TFSI anions provides greatly enhanced mechanical strength and good thermal resistance.•The IL immobilized gel electrolyte possesses intriguing self-healing properties that can recover from severe mechanical damage/breakage.•The IL immobilized gel electrolyte provide high ionic conductivity and stable electrochemical window for Li anodes and high-voltage cathodes.
Dye-Sensitized Solar Cells Hagfeldt, Anders; Boschloo, Gerrit; Sun, Licheng ...
Chemical reviews,
11/2010, Letnik:
110, Številka:
11
Journal Article
Recenzirano
Dye-sensitized solar cells have the potential to design cells with flexibility in transparence, color and shape. The topic of sensitization with the use of molecular dyes is discussed.
Display omitted
•Rational design of novel CuS@PEDOT hybrid negative electrode is demonstrated.•Faradaic nanoarchitectured Co–V–Se arrays are investigated as a positive electrode.•A high energy ...density flexible quasi-solid-state ASC device is fabricated.•The ASC device can blow different colored LEDs and power an electrical motor fan.
For the development of high‐performance modern electronics, fabrication of high-energy density flexible supercapacitors (SCs) composed of advanced functional electrodes with tailored nanoarchitectures is of great significance. Faradaic copper sulphide (CuS) with high theoretical capacity promises great potential as a negative electrode in SCs and to further boost its electrochemical performance, an effective strategy of rational surface engineering by electronically conducting poly(3,4-ethylenedioxythiophene) (PEDOT) is hereby proposed. Herein, construction of novel nanostructured CuS@PEDOT hybrid negative electrode on mechanically flexible conducting carbon cloth (CC) substrate (CC/CuS@PEDOT) via a combined solvothermal and potentiostatic electrodeposition route is successfully demonstrated. Benefiting from high intrinsic reactivity and microstructural characteristics, the CC/CuS@PEDOT hybrid exhibits a marked improvement in areal capacity and ultralong electrochemical cycling stability. As the positive electrodes, nanoarchitectured CC/Co–V–Se (CC/CVS) arrays are prepared and investigated. A novel alkaline polymer gel electrolyte-based quasi-solid-state asymmetric supercapacitor (ASC) assembled with optimized CC/CuS@PEDOT hybrid negative electrode and CC/CVS positive electrode delivers a maximum volumetric energy density of 2.21 mWh cm−3 and superior cycling life (96.7% capacity retention after 10,000 cycles). Additionally, for the ASC device, no obvious performance loss upon bending or twisting is observed, ensuring its adaptability for modern portable and wearable energy storage devices.
Flexible energy storage devices gained lot of substantial research interest in the recent decade as their special features and potential applications in different portable electronic devices such as ...smart sensors, actuators, mobiles, flexible touch screens and electronic newspapers, etc. Therefore, to develop such devices, the flexible electrode and electrolytes with desired mechanical and electrochemical properties are required. In present article, porous nanostructured MnO2 thin films are prepared directly on flexible stainless steel substrate through chemical bath deposition (CBD) method. Further, flexible all-solid-state thin film symmetric supercapacitors (FASSTF-SSCs) have been fabricated using identical MnO2 electrodes with carboxymethyl cellulose- Na2SO4 (CMC-Na2SO4) gel electrolyte. Our results, demonstrate that 0.7μm thick FASSTF cell exhibits specific capacitance of 145Fg−1 with specific energy of 16Whkg−1 and excellent cycling stability after 2500 cycles. In addition, we have presented demonstration of lighting of two light emitting diodes (LEDs) for 135s which finally confirms the potential applicability of MnO2 based solid-state symmetric cells for high-performance flexible energy storage devices.
Recently, dual-graphite batteries (DGBs) receive growing attention for their advantages of high working voltage, environmental friendliness and inexpensive. However, the conventional liquid organic ...electrolytes used in DGBs still possess issues of safety and electrolyte leakage that might limit their further development. Herein, a non-flammable (DMPI+)(AlCl4−) ionic liquid (DAIL) is embedded into a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) matrix to prepare a (DMPI+)(AlCl4−) polymer gel electrolyte (DAPGE) for solving these conventional issues. The DAPGE, as both the electrolyte and separator, is characterized and electrochemically tested in DGB, which shows favourable ionic conductivity of 2.28 × 10−3 S cm−1. The DGB using a DAPGE shows a specific capacity of 80 mAh g−1 at a current density of 100 mA g−1. Moreover, the DGB pouch cell with DAPGE can work well under bending, critical temperature and even exposure to air. Besides, DAPGE decreases the utilization (around 40%) of liquid IL electrolyte as compared to that of conventional glass fibre separators does. Consequently, the application of DAPGE in DGBs shows promise for achieving higher energy density and better robustness.
Display omitted
•Ionic liquid is embedded into PVDF-HFP matrix to prepare DAPGE.•DAPGE demonstrates enhanced safety and electrolyte leakage performance.•DAPGEs are used as both the electrolyte and separator in dual graphite batteries.•DAPGE reduces the electrolyte amount and the potential electrolyte cost in battery.
The present study reports synthesis and analysis of different characteristics of sodium ion conducting polymer gel electrolytes (PGEs) containing sodium salts with BF4−, ClO4− and CF3SO3− anions ...dissolved in tetraethylene glycol dimethyl ether and immobilized in a copolymer matrix consisting of polymethyl methacrylate and poly(vinylidene fluoride-co-hexafluoropropylene). The PGE containing the NaBF4 salt could deliver an ionic conductivity of 1.4 × 10−3 S cm−1 at room temperature along with superior dielectric properties as compared to the electrolytes with NaClO4 and NaCF3SO3 salts. The feasibility of designing sodium-based batteries and EDLCs has been demonstrated using the optimized PGE containing NaBF4 salt. The prototype sodium‑sulfur (NaS) battery designed by utilizing the optimized PGE, sodium amalgam anode and sulfur cathode provides open circuit voltage of ∼2.4 V and initial discharge capacity of ∼163 mA h g−1 and 126 mA h g−1 at discharge currents of 33 mA g−1 and 66 mA g−1, respectively. This optimized PGE also demonstrate good compatibility with AC electrodes in electric double layer capacitor (EDLC) application and delivered a significant specific capacity ∼64 F g−1 at 0.5 mA cm−2 current.
•Effect of different anions BF4, ClO4 and CF3SO3 on the properties of Na+ conducting polymer gel electrolyte is investigated.•Excellent ionic conductivity of 1.48 × 10−3 S cm−1 at room temperature for optimized polymer gel electrolyte.•The prototype Na-S battery shows open circuit voltage of ∼2.4 V and delivers discharge capacity of ∼163 mA h g−1.•The prototype EDLC delivers a significant specific capacity ∼64 F g−1 at 0.5 mA cm−2 current.
In a simple chemical bath deposition, the flexible NiCo2O4 thin films with different nanostructures such as nanoflakes, nanoflowers with the surface composed of nanorods have been synthesized on ...stainless steel by changing the urea concentration of precursor. This study showed that the concentration of urea has a crucial role in the structural conversion of nanostructures. Here, the NiCo2O4 nanoflowers with nanorods like thin film demonstrated superior supercapacitive performance exhibiting a maximum specific capacitance of 702 F g−1 ascribed to the higher electronic conductivity of NiCo2O4 and lower ionic diffusion resistance due to nanoflowers with nanorods like mixed morphology. In further, the higher concentration of urea during synthesis leads to disorientation and overgrowth of the NiCo2O4 nanoflowers which deteriorated its supercapacitive performance. The two flexible solid state symmetric supercapacitor devices have been successfully fabricated using polyvinyl alcohol–KOH and polyvinyl alcohol-LiClO4 gel electrolytes. In comparison, the device with polyvinyl alcohol-LiClO4 gel exhibited superior performance exhibiting a maximum specific capacitance of 132 F g−1 with an energy density of 18.52 Wh kg−1 and a power density of 3.13 kW kg−1.
Display omitted
•Successfully synthesis of NiCo2O4 nanoflowers with nanorods like thin films by a simple, cost effective CBD method.•Influence of urea concentration was evident on structural transformation.•NiCo2O4 nanoflowers with nanorods exhibited remarkable stability with 94.2% for 5000 cycles.•FSS-SC device fabricated with PVA-LiClO4 gel showed superior performance over FSS-SC device fabricated with PVA-KOH gel.
Full cells of structural composite batteries comprising carbon fibre reinforced anodes and cathodes decorated with lithium titanate and LiNi0.3Mn0.3Co0.3O2 (NMC111), respectively, embedded in a ...polymer gel electrolyte were produced. Spread carbon fibres were coated with cathode and anode active materials followed by impregnation with a polymer gel electrolyte consisting of PVDF particles dispersed in an ionic liquid containing a lithium salt. The resulting carbon fibre reinforced electrodes/polymer gel electrolyte prepregs could be easily stored, handled or, if needed, transported. Cathode and anode prepregs were laminated and fused by compression moulding, resulting within a time frame of couple of minutes in full cell structural composite batteries. The batteries were charged and discharged at current densities of 0.1C, resulting in a specific capacity of 35 mAh/gNMC111 and energy density of 5.6 Wh/(kg battery). The composite batteries had a Young's modulus of 4.6 GPa and tensile strength of 32 MPa. A facile layup process enabled proof-of-concept demonstration of ‘all’ carbon fibre full cell multifunctional structural composite batteries.
Display omitted
Aqueous electrolyte presents in batteries have high ionic conductivity. They are economic, non-flammable and offer high energy density. However, restricted thermodynamic electrochemical stable ...potential window of water and its spilling suppresses the use of these batteries. To address these problems, development of a polymer-based electrolyte system is an upcoming area of research. Even, the uses of sodium salts in battery electrolytes are gaining importance over lithium salts due to their abundance and economic feasibility. The present study examines the self-aggregation of star block copolymer Tetronic® 1107 in aqueous medium in the presence of sodium salts viz. sodium chloride, sodium fluoride, sodium nitrate, sodium hexafluoro phosphate and disodium hydrogen phosphate with different anions by cloud point (CP), gelation, dynamic light scattering (DLS) and small angle neutron scattering (SANS). Conductivity and DC polarization measurements are also performed for polymeric systems in the absence and also in the presence of these salts. The gelation behaviour of the block copolymer to reduce leakage problems and proper ionic conductivity of it in the presence of sodium salts make the system a credible choice as a polymer gel electrolyte (PGE).
Display omitted
•A systematic study defining the role of Tetronics® 1107 as a PGE component is reported.•Phase and gelation behaviour of block copolymer under the influence of sodium salts are discussed.•DLS and SANS are utilised for identifying shape and size of the micelles.•Ionic conductivity, transport number measurements are performed for polymer in the presence and absence of salts.•Decrease of CP and an enhanced micellar size and conductivity is observed in the presence of salts.
