I have fabricated polyethylene oxide (PEO) nanofibers doped with HCSA-polyaniline and carbon black. Interestingly, when I source more than 3-4 V through the as-spun fiber mat, an irreversible decrease in resistance occurs (3 orders of magnitude change). I have access to electrochemistry equipment. My question is, can you provide some literature references on how to measure specific capacitance, as well as any other characterization methods that may be useful?
using Cyclic Votametry, EIS in three electrode system. Also from the charge discharge test
From Cyclic Voltamogram, you should be able to calculate the specific capacitance using this equation:
Sp. Capacitance = Voltammetric charge/(potential window × composite loading)
If the shape of CV curve is not the ideal mirror-symmetry, divide integral area of CV curve by the scan rate to obtain the sum of anodic and cathodic voltammetric charges, i.e., Voltammetric charge.
Supercapacitors: Materials, Systems and Applications
Max Lu (Series Editor), Francois Beguin (Editor), Elzbieta Frackowiak (Editor)
ISBN: 978-3-527-32883-3
568 pages
April 2013
Electrochemical Supercapacitors for Energy Storage and Delivery: Fundamentals and Applications
Aiping Yu, Victor Chabot, Jiujun Zhang
For calculating specific capacitance, you should decide on which system you want to work. The calculation of specific capacitance for three electrode system and two electrode system (includes both symmetric and asymmetric system, both have different formula) are different. If you are interested in calculating the specific capacitance of a single electrode, you can opt three electrode system. Cyclic voltammetry will provide you information regarding redox reactions occurring in your system and from the required formula you can calculate the specific capacitance. Galvanostatic charge-discharge method will provide you information about charging time and discharging time of your system. From EIS, you will get the resistances (impedance) of various parameters involved within the system. If you want all the formula, I can provide you. Any other query, you are free to ask. All the best.
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