Search results for "Capacitor"

Structure of nanoporous carbon materials for supercapacitors

2012

Activated carbons with highly developed porous structure and nanosized pores (8 - 11 A) were prepared from alder wood using thermochemical activation method with sodium hydroxide. Properties of the obtained activated carbons were examined by benzene and nitrogen sorption, X-Ray diffraction and Raman spectroscopy. Tests of activated carbons as electrodes in supercapacitors were performed as well. It was found that specific surface area of above mentioned activated carbons was 1800 m 2 /g (Dubinin - Radushkevich). Raman spectroscopy demonstrated the presence of ordered and disordered structures of graphite origin. The performance of activated carbons as electrodes in supercapacitors have show…

Layered double hydroxide nanocomposites based on carbon nanoforms

2020

Abstract Carbon nanoform (CNF)/layered double hydroxide (LDH) nanocomposites have been widely studied in recent years thanks to the combination of properties of both LDH and carbon nanomaterials. They exhibit improved or unexpected properties as a consequence of their hierarchical structures. There are three main reported approaches to prepare the nanocomposites: reassembly of nanocarbons and LDHs, direct formation of LDHs on nanocarbon materials, and the direct synthesis of nanocarbons on the LDH phase. The resulting CNF/LDH nanocomposites exhibit improved conductivity, mechanical properties, and redox reactivity; moreover, the hybridization confers hierarchical porosities and better dispe…

Metal-functionalized covalent organic frameworks as precursors of supercapacitive porous N-doped graphene

2017

Covalent Organic Frameworks (COFs) based on polyimine with several metal ions (FeIII, CoII and NiII) adsorbed into their cavities have shown the ability to generate N-doped porous graphene from their pyrolysis under controlled conditions. These highly corrugated and porous graphene sheets exhibit high values of specific capacitance, which make them useful as electrode materials for supercapacitors.

Cover Picture: Direct Metal‐Free Chemical Vapor Deposition of Graphene Films on Insulating Substrates for Micro‐Supercapacitors with High Volumetric …

2019

A Novel Approach Towards Carbon–Ru Electrodes with Mesoporosity for Supercapacitors

2007

Energy Storage: Giant Enhancement in the Supercapacitance of NiFe–Graphene Nanocomposites Induced by a Magnetic Field (Adv. Mater. 28/2019)

2019

Magnetic Nanocomposites Formed by FeNi3 Nanoparticles Embedded in Graphene. Application as Supercapacitors

2013

A general family of magnetic nanocomposites formed by FeNi3 ferromagnetic nanoparticles (NPs) embedded in a graphitized carbon matrix is reported. The soft chemical approach used relies on the catalytic effect of the NPs resulting from the thermal decomposition of the layered double hydroxide precursor, which acts as a multilayered nanoreactor enabling the formation of a range of carbon nanoforms (CNFs). This is followed by acid treatment of the as-prepared nanocomposites to isolate the different CNFs formed. These range from carbon nano-onions to graphene depending on the temperature of the thermal decomposition. This synthetic process paves the way for the rational design of metal–carbon …

Power management of a battery/supercapacitor system for E-mobility applications

2019

Hybrid Energy Storage Systems (HESS) have been very popular in recent years in different applications, from electric vehicles (EVs) to smart grids and renewable energies, due to the growing need to accumulate electricity. The concept of hybridization arises from the requirement of both high energy and specific power. The battery/supercapacitor (SC) system offers great advantages in a DC bus, giving the opportunity to provide high amounts of power to the loads. In this paper, a system composed of two bidirectional DC-DC converters, one connected to a battery pack and one to a stack of supercapacitors, is presented for a DC bus in electrical mobility (E-Mobility) applications. The proposed co…

A fuel cell-supercapacitor power supply for portable applications

2008

Due to the increasing number and complexity of the available functions, modern handheld devices require higher and higher current slew rates. Customers' requirements lead to a growing interest in longer-lasting power, fast transient response power supply systems and minimization of system weight, volume and cost. Fuel cell based hybrid systems are designed to meet all requirements. In this paper, a fuel cell-supercapacitor hybrid power supply for portable applications is proposed. The power management subsystem is designed and simulation results are shown to test the efficiency of the control algorithm. ©2008 IEEE.

Diagnostic of Supercapacitors based on State Estimation through Extended Kalman Filter

This thesis aimed to analyze the supercapacitor behavior to verify the possibility of the estimation of its internal parameters for diagnostic purposes. The target has been reached firstly by a theoretical analysis which showed that the crucial parameters for diagnostic purposes are the voltage of the non-linear capacitance, since it gives a measure of the stored charge, and the parasitic resistance which limits the maximum allowable current and influences losses. Secondly it has been verified when a supercapacitor parameters are observable and finally an extended Kalman filter to obtain such parameters has been set up. The Thesis demonstrated that a supercapacitor can be modelled by a 2-br…