Electrochemical Performance of Carbon/MnO₂Nanocomposites Prepared via Molecular Bridging as Supercapacitor Electrode Materials

Abstract

The chemical binding of amorphous manganese oxide and carbon particles was achieved with the diazonium chemistry. The synthesis was performed in two steps, with a first step consisting in the surface functionnalization of carbon particles with aminophenyl groups and the subsequent attachment of amorphous manganese oxide particles through generated phenyl groups. The bond between carbon and MnO 2 particles is believed to occur between the carbon from the phenyl groups attached to carbon particles, and the oxygen atoms from the manganese oxide lattice. The capacitance of the carbon/MnO 2 grafted nanocomposite electrode is doubled compared to a simple mixture of its two components. The constant increment in the study and development of energy storage devices such as electrochemical capacitors (ECs) is related to an ever-growing demand of energy of the society. Electrochemical capacitors can be classified by their energy storage mechanisms in two main systems: 1) electrical double layer capacitance which arises from the charge separation at the electrode/electrolyte interface 1 and 2) pseudocapacitive charge storage phenomena where fast and reversible reactions take place.2 At this time, carbon is the commonly used electrode material for electrical double layer capacitor (EDLC) 3 while transition metal oxides and some conductive metal nitrides have demonstrated good performance as pseudocapacitive electrodes. 4 In terms of pseudocapacitive materials, manganese oxide (MnO 2 ) has proved to be one of the most promising materials due to its high energy density, low cost, environmental friendliness and natural abundance. 5 The initial studies describing the use of MnO 2 as an electrode material for ECs were performed by Lee and Goodenough. 6 They reported that amorphous or poorly crystallized MnO 2 powders incorporated into composite electrodes exhibited a capacitor-like electrochemical response in neutral KCl electrolyte, and delivered a specific capacitance of 200 F/g for "bulk" electrodes. Since this initial report, the interest in MnO 2 for ECs applications has grown steadily.Despite its electrochemical performance, the use of MnO 2 is still limited to moderate power applications due to its poor intrinsic electrical conductivity (10 −5 to 10 −6 S.cm −1 ). 7 Up to now, one of the most viable approaches to circumvent this major drawback is the use of a conductive additive such as carbon for improving the percolation through the electrode. For example, carbon black has been used just in a simple mixture with manganese oxide. 28 From all these studies it is clear that an intimate mixture of the carbon additive and manganese dioxide leads to improved power capability, but there is no clear trend to tell which carbon additive leads to the best electrode. However, carbon black is already widely used in ECs technology and thus it should be desirable to focus on this type of carbon when designing MnO 2 based electrode.In this study, we designed a new approach for the preparation of carbon/metal oxide composite electrod...

The Development of Pseudocapacitor Electrodes and Devices with High Active Mass Loading

“…The chemical bridging between MnO 2 and carbon particles has been achieved by diazonium chemistry. [ 29 ] It has been demonstrated that this approach allowed for improved mixing of MnO 2 and carbon particles and facilitated charge transfer. [ 29 ] The capacitance of the carbon/MnO 2 grafted nanocomposite electrode was doubled compared to a simple mixture of its two components.…”

“…[ 29 ] It has been demonstrated that this approach allowed for improved mixing of MnO 2 and carbon particles and facilitated charge transfer. [ 29 ] The capacitance of the carbon/MnO 2 grafted nanocomposite electrode was doubled compared to a simple mixture of its two components. [ 29 ] In another investigation, [ 50 ] it was found that sulfasalazine molecules adsorbed on MnO 2 and carbon nanotubes.…”

“…[ 29 ] The capacitance of the carbon/MnO 2 grafted nanocomposite electrode was doubled compared to a simple mixture of its two components. [ 29 ] In another investigation, [ 50 ] it was found that sulfasalazine molecules adsorbed on MnO 2 and carbon nanotubes. The salicylate‐type bonding allowed for sulfasalazine adsorption on MnO 2 , whereas the adsorption on carbon nanotubes involved π–π and hydrophobic interactions.…”

A Synthesis Method of MnO2/Activated Carbon Composite for Electrochemical Supercapacitors

“…They grafted electroactive anthraquinone (AQ) groups on high specific surface area carbon, afterwards the specific capacitance was doubled because the grafted AQ groups had redox capacitance. [49][50][51] In the latest research of Brousse and Belanger et al, 52 they prepared carbon/MnO 2 nanocomposites via molecular bridging.…”

Lamellar-structured biomass-derived phosphorus- and nitrogen-co-doped porous carbon for high-performance supercapacitors

“…[2][3][4][5][6] Alternatively, pseudocapacitors developed from the surface redox process exhibit higher charge densities but suffer from slower charge transfer kinetics compared to EDLCs. 1,7,8 Hence, one of the most critical aspects in the development of supercapacitor technologies is to provide higher energy and power delivery, while maintaining excellent cycle stability.…”