Electrochemical Supercapacitors from Diamond

Abstract

Boron doped diamond has been utilized as an electrode material to construct an electric double layer capacitor (EDLC) as well as an electrode support to form a pseudocapacitor. In a 1.0 M NaSO 4 solution, the capacitance of diamond EDLC is in the range of 3.6-7.0 µF cm -2 , comparable with those of EDLCs based on other carbon materials. During a charge/discharge process for 1000 cycles at a scan rate of 100 mV s -1 , the capacitance only decreases 5%, indicating high stability and a long life-time of such an EDLC. To improve the capacitance of diamond EDLCs, diamond was coated with a MnO 2 film to construct a pseudosupercapacitor. The MnO 2 films were electrodeposited at a constant potential of 0.9 V vs. Ag/AgCl in 0.2 M MnSO 4 solution. The mass of MnO 2 deposited per unit area, so-called the area density, calculated from the deposition charge, was controlled via the deposition time. The MnO 2 films were characterized using various techniques like SEM, XPS, and Raman spectroscopy, etc. In a 1.0 M NaSO 4 solution, the capacitance of the MnO 2 /diamond based pseudosupercapacitor rises with an increase of the mass of MnO 2 on diamond. Its maximum capacitance was found to be reached at a MnO 2 area density of 24 µg cm -2 . The capacitance obtained from voltammetry is 384 µF, or 326 F g -1 at a scan rate of 10 mV s -1 , which is comparable with the value of 406 µF, or 349 F g -1 , obtained from charge/discharge process at a current density of 3 A g -1 in the potential range 0 to 0.8 V. The capacitance was reduced by 34% after 1000 subsequent charge/discharge cycles carried out at a scan range of 100 mV s -1 .The comparison of the performance of the MnO 2 /diamond pseudosupercapacitor with that of those pseudosupercapacitors based on MnO 2 and other carbon materials indicates that diamond could be suitable for electrochemical supercapacitor applications.

Insight into boron-doped diamond Raman spectra characteristic features

“…It is also recognized as one of the best working electrochemical electrodes with high chemical stability, low capacitive current and a large potential window [2]. Diamond electrodes can be used for fabrication of chemical and biological sensors [3], water treatment systems [4], super capacitors [5], dye sensitized solar cells [6e9], etc. Measurement of boron concentration is an important feedback parameter and is usually determined by Secondary Ions Mass Spectroscopy (SIMS) and Hall effect measurements with the assumption that the acceptor concentration is equal to the hole concentration.…”

Battery‐like Supercapacitors from Vertically Aligned Carbon Nanofiber Coated Diamond: Design and Demonstrator

“…Such a process is automatically controlled by a single-board microcontroller which is also possible to be connected with a USB connector to a computer ( Figure 6a). [2] , diamond network (network) [3] , diamond/silicon nanowires (SiNW) [4] , diamond foam (Foam) [5] , honeycomb diamond (Honeycomb) [6] , porous diamond (Porous) [7] , BDD/Nanotube (Nanotube) [8] , BDD/carbon fiber (CF) [9] , BDD/'black silicon' (bSi) [10] , nitrogen included ultrananocrystalline diamond (N-UNCD) [11] , diamond paper (Paper) [12] , CNFs/BDD (CNF, this [14] , MnO 2 /BDD (MnO 2 ) [2] , Ni(OH) 2 /Diamond Nanowire (Ni(OH) 2 ) [15] , poly(3,4-(ethylenedioxy)thiophene)-coated diamond@silicon nanowires (PEDOT) [16] ; BDD based PC using redox electrolyte (Dia) [3a] , diamond network PC using redox electrolyte (Network) [3a] , CNFs/BDD PC using redox electrolyte (CNF, this work). [18] Cross-linked N-doped CNF network 1.0M H 2 SO 4 5.9 10.0 [19] Mesoporous CNF 6.0 M KOH 5.1 16.0 [20] CNF paper 6.0 M KOH 7.1 9.0 [21] Porous CNF composites 6.0 M KOH 17.0 20.0 [22] Porous CNF 1.0 M H 2 SO 4 ~6.0 20.0 [23] CNFs/BDD [24] ZnO/porous activated CNF 6.0 M KOH 22.7 4.0 [25] MnO 2 /CNF // CNF 0.5 M Na 2 SO 4 36 4.4 [26] CNFs/BDD …”

“…Besides large surface areas, it is more essential for them to facilitate high electron and ion mobility. To grow capacitor electrodes owning such properties, several strategies have been proposed through [2] : 1) improving the conductivity of the electrodes; 2)…”

“…In these studies, various carbon materials with different hybridization of atomic orbitals (sp 2 and sp 3 ), altered allotrope forms of carbon (e.g. fullerenes, nanotubes, graphene and diamond etc.…”

Diamond Nanostructures and Nanoparticles: Electrochemical Properties and Applications

“…Due to their wide electrochemical potential windows, enhanced surface areas, as well as high chemical stability, diamond nanostructures have been used for energy storage and related applications [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56].…”