A method to obtain a Ragone plot for evaluation of carbon nanotube supercapacitor electrodes

2010 ◽  
Vol 25 (8) ◽  
pp. 1500-1506 ◽  
Author(s):  
Akshay S. Raut ◽  
Charles B. Parker ◽  
Jeffrey T. Glass

Electrochemical double layer capacitors, also referred to as supercapacitors, are a promising technology in the field of energy storage. Carbon nanotube (CNT)-based supercapacitors are particularly interesting because of CNTs' high surface area and conductivity. CNT supercapacitors can potentially be used in hybrid electric vehicles due to their higher power density. Comparing energy storage systems that store energy in different ways, such as batteries, fuel cells, supercapacitors, and flywheels, requires that an appropriate set of performance data be collected. A Ragone plot is a log-log plot of a device's energy density versus power density, giving insight into its operational range. A method to obtain Ragone plots for CNT-based supercapacitors in a three-terminal electrochemical cell was adapted from a technique to test commercial capacitors for electric vehicles. Ragone plots for different types of as-grown CNT electrodes in different electrolytes are presented, along with the procedural details of this new method to obtain electrode-specific energy and power densities. Additionally, a theoretical weight calculation for a carbon nanotube film was derived and validated with a direct weight measurement of a CNT film. This weight was used in the specific energy and power densities for the Ragone plot.

2016 ◽  
Vol 4 (38) ◽  
pp. 14586-14594 ◽  
Author(s):  
Helena Matabosch Coromina ◽  
Beatrice Adeniran ◽  
Robert Mokaya ◽  
Darren A. Walsh

The energy/power density of EDLCs containing high surface area carbon nanotube-based electrodes bridges the performance gap between conventional EDLCs and batteries.


2012 ◽  
Vol 1440 ◽  
Author(s):  
Aaron S. George ◽  
Maziar Ghazinejad ◽  
Wei Wang ◽  
Isaac Ruiz ◽  
Mihrimah Ozkan ◽  
...  

AbstractSustainable energy is currently limited by the ability of materials to store energy and deliver it on demand. Allotropes of carbon are attractive for their potential for use in energy storage due to low weight, high chemical stability and low production cost. Carbon nanotubes and graphene can be combined to provide an effective three-dimensional material with high conductivity and high surface area. We demonstrate the use of block copolymers to obtain patterned arrays of iron nanoparticles which give rise to ordered carbon nanotubes with good size distribution. A one-step chemical vapor deposition process for large-area fabrication of the graphene and carbon nanotube hybrid structure is described. Following chemical vapor deposition the hybrid material is demonstrated in a supercapacitor device. The fabricated supercapacitor exhibits high electrical conductivity, and has potential for extremely high energy storage capability.


2020 ◽  
Author(s):  
Ranganatha Sudhakar

Supercapacitors are the integral part of electrochemical energy conversion and storage media. Energy storage mechanism is different in supercapacitors compared to batteries and results in exhibition of excellent power density. The supercapacitor performance is sensitive to material used as electrode, nature of electrolyte, etc. and the very significant is electrode surface nature. Based on the type of energy storage mechanism, supercapacitors are divided as electrochemical double-layer capacitors and pseudocapacitors. There is a practice to have both kind of these materials as electrode materials to achieve high electrochemical performance. Aerogels with inherent characteristics such as large pores, very high surface area, and superior mechanical stability make them superior candidates for electrode materials for high performance electrochemical supercapacitors. In this chapter, aerogels derived from different sources, their suitability and performance in view of electrochemical supercapacitors are discussed.


2021 ◽  
Vol 1 (3) ◽  
pp. 208-218
Author(s):  
Arsal Mehmood

Graphene, a magical development of 2004, has revolutionized today's energy storage technologies. It is nothing but a graphite two-dimensional (2D) allotropic pure carbon layer which is derived from a three-dimensional (3D) shape. Since batteries have been the most common storage device from the invention of the first electrical battery by an Italian physicist Alessandro Volta in 1799 A.D but batteries offer many drawbacks, such as length, weight, poor transient response, low power density, and high internal resistance. In this contrast, the impressive and unique properties of graphene supercapacitor such as high peak current, high surface area, high electrical conductivity, low internal resistance, high load current, long life cycle, high power density, low-temperature charging, and discharging make graphene supercapacitor a replacement of traditional energy storage devices and sets trend for the future. This analytical comparative analysis presents an overview between four traditional batteries and graphene-based supercapacitor. For this regard, dynamic models, modeling equations, and an integrated simulation model for batteries and graphene-supercapacitors under MATLAB/Simulink® 2020a environment is developed. In addition, the effect of temperature on battery output and graphene-supercapacitor is also addressed.


2021 ◽  
Vol 8 ◽  
Author(s):  
Evangelos Koliolios ◽  
Daniel G. Mills ◽  
James J. C. Busfield ◽  
Wei Tan

The high surface area, electrical and mechanical properties of carbon nanotube (CNT) composites has rendered them promising candidates for structural power composites. Nevertheless, it is important to understand their mechanical behaviour before they are applied in energy storage devices amid the safety concerns. This work explores the nail penetration behaviours of supercapacitor specimens consisting of CNT electrodes and pseudocapacitor specimens with carbon nanotube-polyaniline (CNT/PANI) electrodes. Specimens with and without electrolyte were tested. The dry cells without electrolyte follow a power law behaviour, while the wet cells with the electrolyte exhibit a piece-wise nonlinear relationship. The force, voltage and temperature of the supercapacitor were recorded during the nail penetration test. No temperature change or overheating was observed after short-circuit. Moreover, electrochemical testing is performed before and after the specimen penetration. The cyclic voltammetry shows the dramatic loss of capacitance, changing the cell behaviour from capacitor to resistor-like manner. Johnson-Cook model was used to predict the nail penetration behaviour. The coefficients of Johnson-Cook model are calibrated from the experimental load-displacement curves. The finite element model predictions are in a good agreement with the experimental results.


2021 ◽  
Author(s):  
Gurwinder Singh ◽  
Rohan Bahadur ◽  
Ajanya Maria Ruban ◽  
Jefrin Marykala Davidraj ◽  
Dawei Su ◽  
...  

Nanoporous biocarbons derived from waste biomass have created significant attention owing to their great potential for energy storage and conversion and water purification. However, the fabrication technology for these materials...


Author(s):  
Sergey I. Shkuratov ◽  
Jason Baird ◽  
Vladimir G. Antipov ◽  
Christopher S. Lynch ◽  
Shujun Zhang ◽  
...  

The search for ferroelectric materials capable of producing high electric charge and power densities is important for developing a new generation of ultrahigh-power-density ferroelectric energy storage devices and autonomous megawatt power supplies.


Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-26 ◽  
Author(s):  
Helge Skarphagen ◽  
David Banks ◽  
Bjørn S. Frengstad ◽  
Harald Gether

Borehole thermal energy storage (BTES) exploits the high volumetric heat capacity of rock-forming minerals and pore water to store large quantities of heat (or cold) on a seasonal basis in the geological environment. The BTES is a volume of rock or sediment accessed via an array of borehole heat exchangers (BHE). Even well-designed BTES arrays will lose a significant quantity of heat to the adjacent and subjacent rocks/sediments and to the surface; both theoretical calculations and empirical observations suggest that seasonal thermal recovery factors in excess of 50% are difficult to obtain. Storage efficiency may be dramatically reduced in cases where (i) natural groundwater advection through the BTES removes stored heat, (ii) extensive free convection cells (thermosiphons) are allowed to form, and (iii) poor BTES design results in a high surface area/volume ratio of the array shape, allowing high conductive heat losses. The most efficient array shape will typically be a cylinder with similar dimensions of diameter and depth, preferably with an insulated top surface. Despite the potential for moderate thermal recovery, the sheer volume of thermal storage that the natural geological environment offers can still make BTES a very attractive strategy for seasonal thermal energy storage within a “smart” district heat network, especially when coupled with more efficient surficial engineered dynamic thermal energy stores (DTES).


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.


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