Polygonal CuS Nanoprisms Fabricated by Grinding Reaction for Advanced Quasi-Solid-State Asymmetry Supercapacitors

Abstract

The construction of advanced electrode materials with well-connected channels and a satisfactory specific surface area for energy storage techniques, such as supercapacitors, is promising but still challenging. Herein, applying the copper Prussian blue analogue (CuFe-PBA) as the precursor, a polygonal prism-like CuS was synthesized through a grinding method at ambient temperature. The reaction between CuFe-PBA and Na2S led to the substitution of S2– for [Fe­(CN)6]3–, and then, CuS was obtained. Benefitting from the porous precursor, the increased electrochemically active surface area enabled CuS to fully expose the electrochemically active sites and facilitated the effective contact between them and the electrolyte. Moreover, the energy storage mechanism was investigated based on ex situ X-ray photoelectron spectroscopy. The results demonstrated that both the copper and sulfur in CuS are electrochemically active sites, contributing to the distinguished specific capacitance. When used as a negative electrode, the as-fabricated CuS showed the excellent specific capacitance of 1850 F g–1 at 1 A g–1. Then, a quasi-solid-state asymmetry supercapacitor was assembled with CuS as the negative electrode and CuFe-PBA as the positive electrode, possessing an energy density of 56.01 W h kg–1 at a power density of 250.05 W kg–1. Furthermore, the capacitance retention of the asymmetry supercapacitor after 5000 cycles is 83.3%, showing good cycle stability. This work provides an effective strategy toward the design of CuS negative electrode materials with continuously connected channels and outstanding electrochemical properties for energy storage applications.

Heteroatom Modification of Heterostructured CuS/Mn3O4 with Rich Defects for Solid-State Supercapacitors

“…The unchanged peak shape at various scan rates indicates the superior rate capability. The redox peaks suggest the faradic charge storage mechanism, and the reactions involved in the electrochemical process of CuS include the transitions of Cu 3+ /Cu 2+ and Cu 2+ /Cu + . , In the plot of log (peak current density) vs log (scan rate), the b value of O-CuS/Mn 3 O 4 is 0.81, validating the dominated contribution of the adsorption-controlled process (Figure g). Additional fitting results (plot of scan rate vs current density and plot of scan rate 1/2 vs current density) also confirm that CuS/Mn 3 O 4 and O-CuS/Mn 3 O 4 are capacitive-controlled charge storage processes (Figure S14).…”

“…The redox peaks suggest the faradic charge storage mechanism, and the reactions involved in the electrochemical process of CuS include the transitions of Cu 3+ /Cu 2+ and Cu 2+ /Cu + . 48,49…”

CuCoNi–S anchored CoMoO4/MoO3 forming core–shell structure for high-performance asymmetric supercapacitors

“…50 The Cu 2p spectrum displays peaks at 932.6 and 952.5 eV, and 934.8 and 954.8 eV which are assigned to Cu + and Cu 2+ , 51 respectively, demonstrating that Cu + exists in Cu 2+ . 52,53 The peaks at 161.8 and 163.1 eV are attributed to characteristic metal–sulfur bond S 2p 3/2 and S 2p 1/2 , respectively, and the peak at 168.4 eV suggests the appearance of sulfate (S–O) species, 54 which is typical for samples exposed to the atmosphere.…”

“…Dalton Transactions and Cu 2+ , 51 respectively, demonstrating that Cu + exists in Cu 2+ . 52,53 The peaks at 161.8 and 163.1 eV are attributed to characteristic metal-sulfur bond S 2p 3/2 and S 2p 1/2 , respect-ively, and the peak at 168.4 eV suggests the appearance of sulfate (S-O) species, 54 which is typical for samples exposed to the atmosphere. BET specific surface areas and pore diameter distributions of the samples are investigated.…”

Flexible Self-Supporting 3D Electrode Based on 3D Graphene-PPy@Fe-MnCo2O4 Nanostructure Arrays toward High-Performance Wearable Supercapacitors

“…To address this problem, design and construction of three-dimensional (3D) flexible electrodes can provide promising approaches to enhance the specific surface area, ion transportation, and robust structure. − It is well-known that ion diffusion and electron transport rate in the process of energy storage are key points for improving electrode performance. 3D electrodes offer ordered channels for electrolyte ions to sufficiently contact electroactive materials and provide electrolyte ions rapidly at charging and discharging, which is beneficial to cycling stability. − Moreover, 3D electrode architectures have an excellent 3D conductive network and high mass loading of active material, given the supercapacitor high volumetric energy density and good mechanical properties. − Recently, a variety of 3D electrode materials has been reported for supercapacitors, such as 3D graphene/Ni­(OH) 2 , 3D graphene/CoMoO 4 , N-doped 3D graphene networks, 3D graphene/MnO 2 , carbon nanotube, graphene oxide, etc. Among these 3D materials, 3D graphene (G)-based materials have received a great deal of attention as electrode materials because they can quickly transport electrons and have large specific surface area .…”