High-Energy-Density Asymmetric Supercapacitor Based on Layered-Double-Hydroxide-Derived CoNi₂S₄ and Eco-friendly Biomass-Derived Activated Carbon

Abstract

Current work presents a high-performance asymmetric supercapacitor (ASC) using nanostructured cobalt nickel sulfide (CoNi2S4) derived via African marigold flower-like layered double hydroxide (CoNi-LDH) as a cathode and Manihot esculenta-derived activated carbon (MAC) synthesized from oxygen-rich hydrochar as an anode. Optimization for LDH precursors with different times of synthesis was carried out, and best performed CoNi-LDH-12 displayed a specific capacitance of 928 F/g at 1 A/g in a three-electrode system, which was further sulfurized with two different sulfur ratios to obtain CoNi2S4. As-prepared spinel CoNi2S4-800 achieved a remarkable specific capacitance of 1637 F/g at 2 A/g, and the specific capacity was found to be 184 mAh/g, whereas the capacitance for synthesized MAC was found to be 315 F/g at 0.5 A/g in a three-electrode system. The ASC device CoNi2S4//MAC fabricated offered remarkable energy densities of 55.37 and 10.66 Wh/kg at power densities of 3200 W/kg and 10.66 kW/kg, respectively. The prolonged cycle life studies of the ASC device for 5000 cycles achieved a coulombic efficiency of 95.90% with a capacitance retention of ∼90.03%, proving the electrode materials to be promising for energy storage application.

Nickel MXene Nanosheet and Heteroatom Self-Doped Porous Carbon-Based Asymmetric Supercapacitors with Ultrahigh Energy Density

“…The electrochemical performance of NiMX- and EMAC-700-based asymmetric supercapacitors is higher in comparison to that of recently reported MXene-based asymmetric supercapacitors as shown in Table . In all these reports, the poor performance could be ascribed to the (i) instability of MXene (i.e., Ti-, V-, and Nb-based MXene), (ii) incompatibility in the selection of the cathode and anode, and (iii) electrocatalytic activity of electrode materials. ,− By resolving this, we have demonstrated a highly stable nickel-based MXene and activated carbon-based supercapacitor with a 47.6 W h/kg energy density with outstanding stability representing an ideal combination for an asymmetric supercapacitor.…”

Facile Synthesis of Pineapple Waste-Derived Carbon and Polyaniline Composite for High-Energy-Density Asymmetric Supercapacitors

“…The variation of diffusion charge contributions with scan rate shows that the diffusion contribution of PP-800/PANI is significantly higher. This is because PANI improves the polarity of the material and also facilitates a short conduction transport route, which in turn enhances the diffusion contribution and hence results in a high performance. − …”

Synergistic coupling of NiVAl-layered double hydroxide with few-layered Ti3C2Tx–MXene nanosheets for superior asymmetric supercapacitor performance

“…The influence of the aforementioned elements is what causes the Ti 3 C 2 T x -MXene/NiVAl-LDH in this article to demonstrate its exceptional performance when compared with the recently reported similar electrodes, as shown in Table S2 (ESI †). 1,23,28,34,[54][55][56][57][58][59] After it was shown that Ti 3 C 2 T x -MXene/NiVAl-LDH performed remarkably well as the positive electrode material for supercapacitors, a hybrid supercapacitor device was built using these materials: activated carbon (AC) as the negative electrode, 1 M KOH as the electrolyte, and the positive electrode as Ti 3 C 2 T x -MXene/NiVAl-LDH. In order to determine the mass ratio of positive and negative electrodes, cyclic voltammetry (CV) and constant current charge-discharge (GCD) tests were conducted on AC in advance (Fig.…”