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 ◽  
...  

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.

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2750
Author(s):  
Ju-Hwan Kim ◽  
Hye-Min Lee ◽  
Sang-Chul Jung ◽  
Dong-Chul Chung ◽  
Byung-Joo Kim

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.


2013 ◽  
Vol 1497 ◽  
Author(s):  
Tsubasa Funabashi ◽  
Masamichi Sato ◽  
Masao Kitajima ◽  
Shuichi Shoji ◽  
Jun Mizuno

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.


ChemSusChem ◽  
2015 ◽  
Vol 8 (11) ◽  
pp. 1875-1884 ◽  
Author(s):  
Hee-Chang Youn ◽  
Seong-Min Bak ◽  
Myeong-Seong Kim ◽  
Cherno Jaye ◽  
Daniel A. Fischer ◽  
...  

ChemSusChem ◽  
2015 ◽  
Vol 8 (11) ◽  
pp. 1822-1822
Author(s):  
Hee-Chang Youn ◽  
Seong-Min Bak ◽  
Myeong-Seong Kim ◽  
Cherno Jaye ◽  
Daniel A. Fischer ◽  
...  

RSC Advances ◽  
2017 ◽  
Vol 7 (71) ◽  
pp. 44735-44742 ◽  
Author(s):  
Da Sol Jeong ◽  
Je Moon Yun ◽  
Kwang-Ho Kim

The highly porous nitrogen-doped carbon material pyrolyzed from one of PVP/NaOH mixtures with different NaOH contents exhibited a large specific surface area of up to 2400 m2 g−1 and an excellent supercapacitive performance of maximum 478 F g−1.


2020 ◽  
Author(s):  
Tsubasa Okamura ◽  
Kiyoharu Nakagawa

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.


Author(s):  
Yaqi Yang ◽  
Ziqiang Shao ◽  
Feijun Wang

Abstract Due to the low specific capacitance and small specific surface area of conventional carbon materials used as electrode materials for double-layer capacitors, the search for more ideal materials and ingenious preparation methods remains a major challenge. In this study, fractional porous carbon nanosheets were prepared by co-doping Fe and N with chitosan as nitrogen source. The advantage of this method is that the carbon nanosheets can have a large number of pore structures and produce a large specific surface area. The presence of Fe catalyzes the graphitization of carbon in the carbon layer during carbonization process, and further increases the specific surface area of the electrode material. This structure provides an efficient ion and electron transport pathway, which enables more active sites to participate in the REDOX reaction, thus significantly enhancing the electrochemical performance of SCs. The specific surface area of CS-800 is up to 1587 m2 g−1. When the current density is 0.5 A g−1, the specific capacitance of CS-800 reaches 308.84 F g−1, and remains 84.61 % of the initial value after 10,000 cycles. The Coulomb efficiency of CS-800 is almost 100 % after a long cycle, which indicates that CS-800 has more ideal double-layer capacitance and pseudo capacitance.


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