scholarly journals Influences of internal resistance and specific surface area of electrode materials on characteristics of electric double layer capacitors

2017 ◽  
Author(s):  
Yoshiyuki Suda ◽  
Akitaka Mizutani ◽  
Toru Harigai ◽  
Hirofumi Takikawa ◽  
Hitoshi Ue ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electric Double Layer ◽  
Electrode Materials ◽  
Internal Resistance ◽  
Double Layer Capacitors ◽  
Electric Double Layer Capacitors

Electrochemical Properties of Supercapacitors Using Boron Nitrogen Double-Doped Carbon Nanotubes as Conductive Additive

NANO ◽  
2019 ◽  
Vol 14 (07) ◽  
pp. 1950080
Author(s):  
Hao Hu ◽  
Xiaogang Sun ◽  
Wei Chen ◽  
Jie Wang ◽  
Xu Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electric Double Layer ◽  
X Ray ◽  
Nitrogen Doped ◽  
Conductive Additive ◽  
Double Layer Capacitors ◽  
Boron Nitrogen

Carbon nanotubes (CNTs) were doped by ammonium borate as the sources of nitrogen and boron. Under the protection of Ar gas, boron-nitrogen doped CNTs were prepared through nitriding and boronization at high temperature. It is a conductive additive. Then, the obtained CNTs were mixed with activated carbon (AC), SP, sodium dodecyl sulfate (SDS), and cellulose fiber to prepare electrodes. With all the materials, a symmetric electric double-layer supercapacitor (EDLC) was assembled. Next, the materials and electrodes were also characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The factors, chemical connections, and specific surface area of the CNTs were analyzed by X-ray energy spectrum analysis (EDS), X-ray photoelectron spectroscopy (XPS), as well as a specific surface area and porosimetry analyzer (BET). In addition, the electrochemical performances of electric double-layer capacitors were tested with the help of cyclic voltammetry, constant-current charging and discharging, and so on. From the results, we can make a conclusion, that is, both B and N atoms were added into the CNTs and formed bonds successfully with carbon atoms mutually. Besides, the specific surface area is about 1.5 times than that of the CNT. When the charge/discharge current density reaches 50[Formula: see text]mA/g, we can find that the mass specific capacitance of the capacitor can run up to 32.19[Formula: see text]F/g. Also, we observe that the maximum power density is close to 220[Formula: see text]W/kg (700[Formula: see text]mA/g), and the energy density can arrive 9.31[Formula: see text]Wh/kg (50[Formula: see text]mA/g). Based on the impedance test, the electrodes are characterized with low impedance. After 2000 cycles, the boron-nitrogen doped double-layer capacitors maintain a capacitance retention ratio of above 95%. Its power density can still achieve 220[Formula: see text]W/kg when the energy density keeps at 3.46[Formula: see text]Wh/kg. In other words, the electrochemical performance functions of the electric double-layer capacitors are enhanced while the CNTs serve as the electrodes.

Fabrication and Basic Investigation of Flat Lignocellulosic Carbon Material for Self-Supporting Electrodes in Electric Double-Layer Capacitors

2013 ◽  
Vol 1497 ◽  
Author(s):  
Tsubasa Funabashi ◽  
Masamichi Sato ◽  
Masao Kitajima ◽  
Shuichi Shoji ◽  
Jun Mizuno
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Carbon Material ◽  
Electric Double Layer ◽  
Vacuum Ultraviolet ◽  
Electrode Materials ◽  
Picea Jezoensis

ABSTRACTA novel flat, wood-based carbon material with heterogeneous pores, referred to as flat lignocellulosic carbon material (FLCM), was successfully fabricated by carbonizing samples of the softwood Picea jezoensis (Ezomatsu or Jezo spruce, a Japanese conifer). Simultaneous improvements of the specific surface area of the FLCM and the affinity of electric double-layer capacitor (EDLC) for electrolyte solvents were achieved by vacuum ultraviolet/ozone (VUV/O3) treatment. The specific surface area of the VUV/O3-treated FLCM showed a 50% increase over that of the original FLCM. The spectra measured by X-ray photoelectron spectroscopy (XPS) indicated that the number of O-C=O (carboxyl or ester) bonds increased, whereas the number of C-C bonds decreased. Additionally, the feasibility of using the FLCM as a self-supporting electrode in EDLCs was examined by measuring the electrochemical properties in a three-electrode system. The FLCM was confirmed as an appropriate self-supporting EDLC electrode material without warps and cracks. In addition, the FLCM can be used without any binder. Realization of FLCM-based EDLC electrodes with bendability, an area of several tens of square centimeters, and no risk of warp or crack formation, were indicated. Thus, FLCMs present a fascinating class of self-supporting carbon electrode materials for EDLCs.

scholarly journals Application of Porous Carbon Material As Electrode Material of Polyvalent Cation Electric Double Layer Capacitor (EDLC) for High Capacity

2020 ◽  
Author(s):  
Tsubasa Okamura ◽  
Kiyoharu Nakagawa
Keyword(s):  
Energy Density ◽  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electrode Material ◽  
Electric Double Layer ◽  
Electrode Materials ◽  
Power Supplies ◽  
Adsorption And Desorption

Electric double layer capacitors (EDLC) are charged and discharged by the physical adsorption and desorption of electrolyte ions on the electrode surface. EDLC has the advantages of high-speed charge and discharge and long life. EDLC is used in memory backup power supplies such as personal computers and energy regenerative systems for power regenerative brakes in hybrid vehicles. In recent years, demand for applications such as in-vehicle power supplies has increased. Therefore, high energy density is required. The energy density increases by increasing the electrostatic capacity and the potential. In the conventional adsorption and desorption of monovalent cations, only one electron can be exchanged for each cation. In adsorption and desorption, two electrons can be exchanged for each cation. Therefore, it was considered that the capacitance can be increased by using an electrolyte of divalent cations.In this study, Ca2+ was used as the divalent cation. As an organic electrolyte, propylene carbonate (PC) and γ-butyrolactone (GBL), which are commonly used in EDLC research as a solvent and can dissolve the electrolyte used. In addition, the dependence of the specific surface area and pore characteristics of the electrode material on the capacity was examined. Activated carbon and carbon gel were used as electrode materials. The capacitance of Ca2+ electrolyte increased when GBL was used as the solvent. Capacitance increased depending on the specific surface area of electrode materials.

scholarly journals Bamboo-Based Mesoporous Activated Carbon for High-Power-Density Electric Double-Layer Capacitors

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2750
Author(s):  
Ju-Hwan Kim ◽  
Hye-Min Lee ◽  
Sang-Chul Jung ◽  
Dong-Chul Chung ◽  
Byung-Joo Kim
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electrode Material ◽  
Electric Double Layer ◽  
Mesoporous Activated Carbon ◽  
Double Layer Capacitors

Demand for hybrid energy storage systems is growing, but electric double-layer capacitors (EDLCs) have insufficient output characteristics because of the microporous structure of the activated carbon electrode material. Commercially, activated carbon is prepared from coconut shells, which yield an activated carbon material (YP-50F) rich in micropores, whereas mesopores are desired in EDLCs. In this study, we prepared mesoporous activated carbon (PB-AC) using a readily available, environmentally friendly resource: bamboo. Crucially, modification using phosphoric acid and steam activation was carried out, which enabled the tuning of the crystal structure and the pore characteristics of the product. The structural characteristics and textural properties of the PB-AC were determined, and the specific surface area and mesopore volume ratio of the PB-AC product were 960–2700 m2/g and 7.5–44.5%, respectively. The high specific surface area and mesopore-rich nature originate from the phosphoric acid treatment. Finally, PB-AC was used as the electrode material in EDLCs, and the specific capacitance was found to be 86.7 F/g for the phosphoric-acid-treated sample steam activated at 900 °C for 60 min; this capacitance is 35% better than that of the commercial YP-50F (64.2 F/g), indicating that bamboo is a suitable material for the production of activated carbon.

scholarly journals Insights into the influence of the pore size and surface area of activated carbons on the energy storage of electric double layer capacitors with a new potentially universally applicable capacitor model

2019 ◽  
Vol 21 (6) ◽  
pp. 3122-3133 ◽  
Author(s):  
Ruben Heimböckel ◽  
Frank Hoffmann ◽  
Michael Fröba
Keyword(s):  
Energy Storage ◽  
Pore Size ◽  
Surface Area ◽  
Double Layer ◽  
Electric Double Layer ◽  
Activated Carbons ◽  
Porous Carbons ◽  
Pore Sizes ◽  
Double Layer Capacitors ◽  
Electric Double Layer Capacitors

A new capacitor model that confirms the non-constant capacitive contribution of different pore sizes and provides the possibility of simulating the capacitance values of porous carbons.

scholarly journals Preparation and characterization of bamboo-based activated carbons as electrode materials for electric double layer capacitors

Carbon ◽  
2006 ◽  
Vol 44 (8) ◽  
pp. 1592-1595 ◽  
Author(s):  
Yong-Jung Kim ◽  
Byoung-Ju Lee ◽  
Hiroaki Suezaki ◽  
Teruaki Chino ◽  
Yusuke Abe ◽  
...  
Keyword(s):  
Double Layer ◽  
Electric Double Layer ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Double Layer Capacitors ◽  
Electric Double Layer Capacitors
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