scholarly journals Effect of KOH on the Energy Storage Performance of Molasses-Based Phosphorus and Nitrogen Co-Doped Carbon

Electrochem ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 29-41
Author(s):  
Iris Denmark ◽  
Samantha Macchi ◽  
Fumiya Watanabe ◽  
Tito Viswanathan ◽  
Noureen Siraj

In this study, we have evaluated the effect of potassium hydroxide (KOH) on the energy storage performance of metal-free carbon-based materials prepared from molasses. Molasses are a renewable-resource biomass and economical by-product of sugar refinement, used here as a carbon precursor. Two co-doped carbon materials using molasses were synthesized via a time and cost-efficient microwave carbonization process, with ammonium polyphosphate as a phosphorus and nitrogen doping agent. The phosphorus and nitrogen co-doped carbon (PNDC) samples were prepared in the presence and absence of a chemical activating agent (KOH), to study the role of chemical activation on PNDCs. Physical characterizations were performed to gain insight into the composition, pore size and topographical data of each material. Electrochemical characterization via cyclic voltammetry in 1 M sulfuric acid (H2SO4) as well as in 6 M KOH as electrolytes, revealed high current density and specific capacitance for the chemically activated material (PNDC2) compared to one without chemical activation (PNDC1). The capacitance value of 244 F/g in KOH electrolyte was obtained with PNDC2. It is concluded that addition of KOH prior to carbonization increases the surface functionality, which significantly enhances the electrochemical properties of the PNDC material such as current density, stability, and specific capacitance.

NANO ◽  
2017 ◽  
Vol 12 (08) ◽  
pp. 1750103 ◽  
Author(s):  
Guofu Ma ◽  
Wei Tang ◽  
Kanjun Sun ◽  
Zhiguo Zhang ◽  
Enke Feng ◽  
...  

Coprinus comatus-based nitrogen-doped activated carbon (N-ACC) is prepared by chemical activation and nitrogen-doped methods. The N-ACC possesses large specific surface areas (976.96[Formula: see text]m2[Formula: see text]g[Formula: see text]), high nitrogen contents (11.53[Formula: see text]wt.%), and super hydrophilicity. As electrode material for supercapacitors, the N-ACC shows remarkable electrochemical performance, such as 346[Formula: see text]F[Formula: see text]g[Formula: see text] maximum specific capacitance at a current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text], which retains 260[Formula: see text]F[Formula: see text]g[Formula: see text] even at a high current density of 10[Formula: see text]A[Formula: see text]g[Formula: see text] (about 75% capacitance retention) in 2[Formula: see text]M KOH aqueous electrolyte. The assembled N-ACC//N-ACC symmetric supercapacitor exhibits energy density of 14.63[Formula: see text]Wh[Formula: see text]kg[Formula: see text] at power density of 810[Formula: see text]W kg[Formula: see text], and excellent cycling stability with 92% specific capacitance retention after 10000 cycles in the voltage range 0–1.8[Formula: see text]V in 0.5[Formula: see text]M Na2SO4 aqueous solution. These results indicate that the N-ACC as electrode materials can be used for high performance supercapacitors.


2015 ◽  
Vol 44 (19) ◽  
pp. 9221-9229 ◽  
Author(s):  
K. Bhattacharya ◽  
P. Deb

Here, the novel Fe3O4-C hybrid nanocomposite demonstrates high specific capacitance (S.C.) than the pristine Fe3O4nanospheres due to the presence of the highly conducting carbon quantum dots.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Guo-Qun Zhang ◽  
Bo Li ◽  
Mao-Cheng Liu ◽  
Shang-Ke Yuan ◽  
Leng-Yuan Niu

Transition metal phosphide alloys possess the metalloid characteristics and superior electrical conductivity and are a kind of high electrical conductive pseudocapacitive materials. Herein, high electrical conductive cobalt phosphide alloys are fabricated through a liquid phase process and a nanoparticles structure with high surface area is obtained. The highest specific capacitance of 286 F g−1 is reached at a current density of 0.5 A g−1. 63.4% of the specific capacitance is retained when the current density increased 16 times and 98.5% of the specific capacitance is maintained after 5000 cycles. The AC//CoP asymmetric supercapacitor also shows a high energy density (21.3 Wh kg−1) and excellent stability (97.8% of the specific capacitance is retained after 5000 cycles). The study provides a new strategy for the construction of high-performance energy storage materials by enhancing their intrinsic electrical conductivity.


Nanoscale ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 5581-5590 ◽  
Author(s):  
Lin Zhu ◽  
Ziliang Chen ◽  
Yun Song ◽  
Pei Wang ◽  
Yingchang Jiang ◽  
...  

Mn0.33Co0.67N nanosheets were reported as a novel anode material for LIBs with a high reversible capacity close to 900 mA h g−1 after 150 cycles at a current density of 500 mA g−1, which is superior to 749 mA h g−1 of undoped CoN due to the enhancement of regeneration of Co–N bonds.


2014 ◽  
Vol 105 (16) ◽  
pp. 162604 ◽  
Author(s):  
Yoon-Jun Kim ◽  
Jeremy D. Weiss ◽  
Eric E. Hellstrom ◽  
David C. Larbalestier ◽  
David N. Seidman

2018 ◽  
Vol 2 (2) ◽  
pp. 455-465 ◽  
Author(s):  
Yufang Cao ◽  
Lijing Xie ◽  
Guohua Sun ◽  
Fangyuan Su ◽  
Qing-Qiang Kong ◽  
...  

The N–P co-doped hollow carbon microtubules derived from kapok exhibited an excellent capability in the organic electrolyte systems.


2015 ◽  
Vol 08 (04) ◽  
pp. 1550031 ◽  
Author(s):  
Baolin Xing ◽  
Jianliang Cao ◽  
Yan Wang ◽  
Guiyun Yi ◽  
Chuanxiang Zhang ◽  
...  

A lignite-based activated carbon (LAC) for electrochemical capacitors (ECs) was prepared from high moisture lignite by KOH activation, and the as-prepared sample was characterized by the N 2-sorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performances of ECs with activated carbon as electrodes in 3 M KOH aqueous solution were evaluated by constant current charge-discharge and cyclic voltammetry. The LAC exhibits a well-developed surface area of 2581 m2/g, a relative wide pore size distribution of 0.5–10 nm. The ECs with LAC as electrode materials presents a high specific capacitance of 392 F/g at a low current density of 50 mA/g, and still remains 315 F/g even at a high current density of 5 A/g. The residual specific capacitance is as high as 92.9% after 2000 cycles. Compared with the commercial activated carbon (Maxsorb: Commercial product, Kansai, Japan), the LAC based electrode materials shows superior capacitive performance in terms of specific capacitance and charge–discharge performance at the high current density.


Author(s):  
Yihan Shi ◽  
Ming Zhang ◽  
Junshan Zhao ◽  
Liu Zhang ◽  
Xumei Cui ◽  
...  

Abstract In this work, MnO2&SDBS electrodes with nano-honeycomb morphology were prepared by ultrasound-assisted electrochemical deposition using sodium dodecylbenzene sulfonate (SDBS) as a surfactant agent. The effect and mechanism of SDBS on the morphology of MnO2 nanomaterials during the preparation of MnO2 by electrochemical anodic oxidation was systematically investigated by varying the content of SDBS in the precursor solution. When the SDBS concentration is 2 g\bulletL-1, the resulting electrode has the best electrochemical performance, and the specific capacitance is up to 407 F\bulletg-1 at the current density of 1000 mAg-1. To further enhance its performance, a carbon coating layer was deposited on the surface of the electrode using a method similar to chemical vapor deposition. Finally, the MnO2&SDBS@C electrode with a three-dimensional net-to-film composite structure with a high specific surface area, hierarchical structure and interconnect with nickel foam supports were obtained. The electrode has excellent electrochemical performance, and the specific capacitance is still up to 289 Fg-1 at a high current density of 5000 mAg-1. Furthermore, the specific capacitance of the electrode was maintained at 76.7% after 5000 cycles of charging and discharging at a current density of 2000 mAg−1.


Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 553 ◽  
Author(s):  
Hengshuo Zhang ◽  
Wei Xiao ◽  
Wenjie Zhou ◽  
Shanyong Chen ◽  
Yanhua Zhang

Hierarchical micro-mesoporous carbon (denoted as HPC-2 in this study) was synthesized by pre-carbonization of biomass Sichuan pepper followed by KOH activation. It possessed well-developed porosity with the specific surface area of 1823.1 m2 g−1 and pore volume of 0.906 cm3 g−1, and exhibited impressive supercapacitive behaviors. For example, the largest specific capacitance of HPC-2 was tested to be ca. 171 F g−1 in a three-electrode setup with outstanding rate capability and stable electrochemical property, whose capacitance retention was near 100% after cycling at rather a high current density of 40 A g−1 for up to 10,000 cycles. Furthermore, a two-electrode symmetric supercapacitor cell of HPC-2//HPC-2 was constructed, which delivered the maximum specific capacitance and energy density of ca. 30 F g−1 and 4.2 Wh kg−1, respectively, had prominent rate performance and cycling stability with negligible capacitance decay after repetitive charge/discharge at a high current density of 10 A g−1 for over 10,000 cycles. Such electrochemical properties of HPC-2 in both three- and two-electrode systems are superior or comparable to those of a great number of porous biomass carbon reported previously, hence making it a promising candidate for the development of high-performance energy storage devices.


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