Search

Ternary transition metal sulfides have emerged as promising electrode materials for next-generation supercapacitors because of their potential ability to simultaneously ensure high conductivity and stability during electrochemical reactions. In the present investigation, MoS2 incorporated CuCo2S4 nanocomposites have been successfully synthesized using a hydrothermal technique. The structural, morphological, elemental and chemical properties of the prepared CuCo2S4–MoS2 nanocomposite were investigated extensively. High resolution transmission electron microscopy imaging demonstrated the successful synthesis of CuCo2S4–MoS2 nanocomposites. The electrochemical capacitor performance of the nanocomposite has been evaluated both in three-electrode and symmetric two-electrode systems. In the three-electrode cell, a specific capacitance of 820 F g−1 was achieved for the CuCo2S4–MoS2 electrode at a current density of 0.5 A g−1 which is considerably higher than that of the CuCo2S4 electrode (249 F g−1). We observed that the charge storage capacity, conductivity and stability of CuCo2S4 improved significantly due to the incorporation of MoS2. Finally, an asymmetric supercapacitor was fabricated by assembling the CuCo2S4–MoS2 electrode with an activated carbon electrode which demonstrated a large stable working potential window of 1.6 V. Excellent long-term cyclic stability of 89% retention after 1000 galvanostatic charge-discharge cycles was evident. As a solid state device, it delivered a high energy density of 38.22 W h kg−1 at a power density of 400 W kg−1 and lit up one red LED for 170 s, indicating its superiority over the conventional Cu-Co based supercapacitors. [ABSTRACT FROM AUTHOR]

We demonstrate a facile efficient way to fabricate activated carbon nanosheets (ACNSs) consisting of hierarchical porous carbon materials. Simply heating banana leaves with K2CO3 produce ACNSs having a unique combination of macro‐, meso‐ and micropores with a high specific surface area of ∼1459 m2 g−1. The effects of different electrolytes on the electrochemical supercapacitor performance and stability of the ACNSs are tested using a two‐electrode system. The specific capacitance (Csp) values are 55, 114, and 190 F g−1 in aqueous 0.5 M sodium sulfate, organic 1 M tetraethylammonium tetrafluoroborate in acetonitrile, and pure ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIM][PF6]) electrolytes, respectively. The ACNSs also shows the largest potential window of 3.0 V, the highest specific energy (59 Wh kg−1) and specific power (750 W kg−1) in [BMIM][PF6]. A mini‐prototype device is prepared to demonstrate the practicality of the ACNSs. [ABSTRACT FROM AUTHOR]

This study reports a simple one-step hydrothermal method for the preparation of a Ni(OH) 2 and MnO 2 intercalated rGO nanostructure as a potential supercapacitor electrode material. Having highly amorphous rGO layers with turbostratic and integrated wrinkled flower-like morphology, the as-prepared electrode material showed a high specific capacitance of 420 F g -1 and an energy density of 14.58 Wh kg -1 with 0.5 M Na 2 SO 4 as the electrolyte in a symmetric two-electrode. With the successful intercalation of the γ-MnO 2 and α-Ni(OH) 2 in between the surface of the as-prepared rGO layers, the interlayer distance of the rGO nanosheets expanded to 0.87 nm. The synergistic effect of γ-MnO 2 , α-Ni(OH) 2 , and rGO exhibited the satisfying high cyclic stability with a capacitance retention of 82% even after 10 000 cycles. Thus, the as-prepared Ni(OH) 2 and MnO 2 intercalated rGO ternary hybrid is expected to contribute to the fabrication of a real-time high-performing supercapacitor device., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

A variety of methods for removing heavy metal ions from wastewater have been developed but because of their low efficiency, further production of toxic sludge or other waste materials, high expense, and lengthy procedures, limited progress has been achieved to date. Polymeric hydrogel has been attracting particular attention for the effective removal of heavy metal ions from wastewater. Here, ionogenic polymeric hydrogels were prepared by free-radical copolymerization of a neutral acrylamide (AAm) monomer with an ionic comonomer in the presence of a suitable initiator and a cross-linker. Different types of ionic comonomers such as strongly acidic: 2-acrylamido-2-methylpropane sulfonic acid, weakly acidic: acrylic acid (AAc), and zwitterionic: 2-methacryloyloxy ethyl dimethyl-3-sulfopropyl ammonium hydroxide with varying amounts were incorporated into the poly(AAm) networks to fabricate the hydrogels. The heavy metal ions (Fe 3+ , Cr 3+ , and Hg 2+ ) removal capacity of the fabricated hydrogels from an aqueous solution via electrostatic interactions, coordination bond formation, and a diffusion process was compared and contrasted. The poly(AAm) hydrogel containing weakly acidic AAc groups shows excellent removal capacity of heavy metal ions. The release and recovery of heavy metal ions from the hydrogel samples are also impressive. The compressive strength of hydrogels was found to be significantly high after incorporating heavy metal ions that will increase their potential applications in different sectors., Competing Interests: The authors declare no competing financial interest., (© 2020 The Authors. Published by American Chemical Society.)