An efficient synthesis of 3-substituted-5-arylamino-1,2,4-thiadiazoles through intramolecular oxidative S-N bond formation of imidoyl thioureas by phenyliodine(III) bis(trifluoroacetate) is reported. The protocol features a metal-free approach, broad substrate scope, very short reaction times, good to excellent yields, and simple starting materials.

The rechargeable Zn 2+ ion batteries are promising for the sustainable energy storage device applications. Recently they have been extensively evaluated for finding new cathode material and prevention of dendrite growth at Zn plate anode. Herein we have evaluated redox active organic molecule 7,7,8,8Tetracyanoquino dimethane (TCNQ) as a cathode material for aqueous zinc battery with zinc plates as anode in 1 M ZnSO 4 . The charging/discharging of the battery was associated with formation and deformation of Zn-TCNQ complex, which was confirmed by XRD and FTIR. The specific capacity of cathode was found to be 123.2 mAh g −1 at 100 mA current density with 96% coulombic efficiency. Whereas specific capacity at 1 A current density was found to be 60 mAh g −1 with 94% coulombic efficiency. In a cycling experiments we observed the fading of capacity with time by partial dissolution of Zn-TCNQ complex. The fading of capacity was prevented by confining TCNQ molecules inside the nano structures of newly prepared covalent organic polymers. The confinement remarkably increased the capacitance to 171 mAh g −1 at 1 A current density. As the material is readily available and the absence of toxic inflammable volatile organic electrolytes in our battery this material offers a very good choice as cathode material for zinc battery.

Low voltage, non‐gassing electroosmotic pump (EOP) was assembled with poly(2‐ethyl aniline) (EPANI)‐Prussian blue nanocomposite electrode and commercially available hydrophilic PVDF membranes. The nanocomposite material combines excellent oxidation/reduction capacity of EPANI with exceptional stability by shuttling of proton between Prussian blue nanoparticles and EPANI redox matrix. The flow rate was highly dependent on the electrode composition but it was linear with applied voltage. The flow rate at 5 V for different nanocomposite, EPANI, EPANI‐A, EPANI‐B, and EPANI‐C were 127.29, 187.41, 148.51, and 95.47 µL/min cm2, respectively, which increases substantially with increase in the Prussian blue content. The obtained best electro osmotic flux was 43 µL/min/V/cm2 for EPANI‐A. It was higher than most of the EOP assembled using polyquinone and polyanthraquinone redox polymers. The assembled EOP remained exceptionally stable until the electrode charge capacity was fully utilized. The best EOP produces a maximum stall pressure of 1.2 kPa at 2 V. These characteristics make it suitable for a variety of microfluidic/device applications.

Small redox active organic molecules present the challenges of excessive dissolutions, interfacial crystallization, side reactions such as self-coupling and polymerizations. To address this, we have developed a quinone containing methylene bridged covalent organic framework (COF) as electrode material for aqueous zinc-based storage device. The capacity of the neat polymer was found to be 162.27 mAhg−1 at 0.1 A current density. Owing to the outstanding insolubility of the polymer, the excessive dissolution as well as the interfacial crystallization of the material were ruled out. We anticipated that the low capacity was due to the dendrite formation on Zinc anode surface during prolonged cycling experiment. The dendrite formation was controlled by performing the experiments in a silica dispersed electrolyte which was identified by analyzing the scanning electron microscopy images. Under this condition remarkable capacity retention was achieved with nearly 100% columbic efficiency. For further electrochemical enhancement, carbon nanotubes were loaded during the synthesis of the COF and the capacity was found to be 248 mAhg−1 and remained showing 241 mAhg−1 after 1000 continuous cycling and remained 218 mAhg−1 after 5000 cycles in the fumed silica dispersed electrolyte. Having specific structural robustness as well as their chemical inertness and extensive pi conjugation in addition to their good conductivity, carbon nano tubes (CNTs) impart very significant role to enhance the electrochemical characteristics of our material. A pouch cell was assembled to evaluate the applicability of the material and the open circuit potential (OCP) was found to be 1.196 V for 48 h which indicates the suitability of the material as pseudocapacitor.

Zinc-based energy storage is increasingly getting attention owing to its outstanding characteristics over to the other systems. Their high abundance, user-friendliness, environmental benignity, and low reduction potential which can avoid unwanted hydrogen evolution are some of the attractive features. Appropriate membrane selection for the zinc-based redox flow battery is challenging. Herein we report the composite of SPEEK (sulfonated polyether ether ketones) with covalent organic frameworks (COF) as a potential membrane for zinc-based redox flow battery. Biphenyl-based knitting type COF was prepared, post sulfonated, and blended with SPEEK. In a Zn/I2 redox flow battery system, the discharge capacity was found to be 19.8 AhL-1, 17.4 AhL-1, 15.1 AhL-1 for 20%, 15%, 10% SCOF loading, respectively, against 14.5 AhL-1 for pristine SPEEK at 20 mAcm-2 current density. The capacity was improved by about 36% higher than the neat SPEEK membrane. This improvement in the battery performance might be due to the higher ionic conductivity and hydrophilicity after SCOF loading. We found that the 15% loading was the maximum limit for the battery performance, beyond which the energy efficiency was found to be fading, which is due to the excessive dendrite growth on the membrane surface.

Aqueous zinc batteries are increasingly gaining attention of the researchers in recent years because of their environmental and user friendliness as well as the economic benefits of the zinc metal. Herein we report a ferrocene based organic cathode synthesized by following green chemistry principle and stabilized by low temperature thermal encapsulation in multiwalled carbon nano tubes (MWCNTs) for stable electrochemical performance. Successful intercalation was confirmed by XRD, Raman, FTIR spectra, TEM-HAADF imaging. Without encapsulation, material exhibited initial capacity of 64.7 mAhg-1 which was drastically faded with time due to dissolution of active material. However, by low temperature thermal encapsulation, the capacity was remarkably improved to 71.3 mAhg-1 with 94% columbic efficiency and 91% capacity retention at a current density of 75mAg-1 in a 100 charge/discharge cycles. The stability of the electrode has been explained on the basis of a friendly host-guest interaction between CNTs and the organic molecules by π-π stacking, dipole-dipole and dipole induced dipole interactions with detailed electrochemical and spectroscopic characterization. From this study we conclude that the thermal intercalation in MWCNTs has been found to be excellent method to stabilize the electrode materials in battery application.

Phenothiazine is a p-type cathode that follows the anion pairing mechanism, where the electrode undergoes extensive expansion and contraction during cycling, which affects deleteriously the battery performance. Herein, we tried...

Self-doping strategy is well-known for enhanced ion transport in electrode materials. Herein we report self-doped thiophenebased conducting polymer (SDTP), where the dopant SO 3 À groups function as the hanging ion carrier mimicking a 'pendulum hand'. It synergistically improves the battery performance, ideally mitigating the dissolution and the enhance ion diffusion kinetics. The diffusion coefficient was determined by three different techniques, i. e., electrochemical impedance spectroscopy (EIS), galvanostatic intermittent titration technique (GITT), and cyclic voltammetry at different sweep rates. The calculated diffusion coefficient for the SDTP was found to be much better than the neat thiophene polymer (NTP). The material was evaluated as a cathode for an aqueous zinc-ion battery. The specific capacitance of the NTP was found to be 178 mAh g À 1 at 50 mA g À 1 current density. It was drastically reduced to 167, 118.2, and 83 mAh g À 1 after the 5 th , 10 th , and 30 th respective cycles. The polymer SDTP outperformed with a specific capacity of 274, 208, 159, 127, 108 mAh g À 1 at current densities of 50, 100, 200, 300, 400 mA g À 1 . It exhibited good rate reversibility, and excellent rate stability with ~99 % Coulombic efficiency in an over 4000 continuous cycles at 50 mA g À 1 suggesting wise molecular engineering is necessary to improve battery performance.