Boron-Doped Diamond Powders for Aqueous Supercapacitors with High Energy and High Power Density

Abstract

The electrochemical properties of boron-doped diamond powder (BDDP) were investigated as a step toward its application to aqueous electric double-layer capacitors (EDLCs). Conductive BDDPs (particle size: 150, 350, and 3500 nm) were prepared by depositing a BDD layer on the surface of a diamond powder (DP) core with various particle sizes (100, 300, and 2600 nm) via microwave plasma-assisted chemical vapor deposition. The 150-nm-sized BDDP (BDDP-150) had a relatively large Brunauer-Emmett-Teller (BET) specific surface area (106 m 2 /g). Cyclic voltammetry of the BDDP electrodes in 1.0 M H 2 SO 4 with a symmetric two-electrode system showed an operating voltage of 1.5 V, which is much larger than that of an activated carbon (AC) electrode (0.8 V). In addition, compared to the AC electrode, the BDDP electrodes showed lower capacitance-decrease ratios at fast scan rates. Hence, BDDP-150 had greater energy and power densities than the AC electrode under high rate conditions in the aqueous electrolyte. As the BDDP electrode had a larger bulk density than the AC electrode, aqueous EDLC using BDDP can be expected to be used as a space-saving electric energy storage system suitable for high-speed charging and discharging.

Heteroatom‐Doped and Oxygen‐Functionalized Nanocarbons for High‐Performance Supercapacitors

“…[119] Since the potential window of sp 2 -bonded carbons is limited to only 1.2 V in aqueous electrolyte, [120] the focus is shifted to the conductive B-doped diamond owing to their ability to operate in a broader potential window along with notable electrochemical properties. [79,121] The results examined in this section suggest that in spite of remarkable changes in the properties of B-doped nanocarbons, the specific capacitance mostly remains within a similar range compared to pristine nanocarbons. Therefore, introduction of alternative dopants or codoping may be a likely promising solution, as discussed in the following sections.…”

Boron-doped Nanodiamond as an Electrode Material for Aqueous Electric Double-layer Capacitors

“…The higher suitability of the BDND is further evinced when considering the volumetric capacitance (Fig. 6b) because the bulk density of the BDND electrode layer (0.52 g/cm 3 ) was larger than that of the AC electrode layer (0.23 g/cm 3 ) 27 . The energy density was calculated using the capacitance extracted from Figs.…”

“…The capacitance of the BDDP was found to increase upon decreasing the diameter. Furthermore, cyclic voltammetry (CV) measurements performed with a symmetric two-electrode cell showed a large cell voltage of 1.5 V in 1 M H 2 SO 4 , whereas that for activated carbon (AC) was 0.8 V 27 .…”

Capacitors Consisting of an Aqueous Electrolyte of the Widest Potential Window —Development towards the Recovery of Regenerating Energy of Automobiles—

“…Under such a highly concentrated condition, less than four water molecules exist per one sodium ion, which is smaller than the first coordination sphere of Na + . Furthermore, ClO 4 ¹ also restricts the movement of water. Since water molecule is highly restricted by Na + and ClO 4 ¹ , hydrogen bond could be weakened or destroyed.…”

“…Recently, a number of papers were concerned for the development of capacitor using aqueous electrolytes. [4][5][6][7][8][9][10][11][12][13][14][15] Kondo and Yuasa et al 4 used SSPAS as an electrolyte for the capacitor containing boron-doped diamond powders to determine the energy density of approximately 20 Wh/kg. In a paper by Chinese Academy of Science, various aqueous electrolytes were compared with organic ones based on the costs as well as the electro-chemical performances of these electrolytes.…”