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Updated: Oct 1, 2025
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Evaluating the Electrochemical Properties of Supercapacitors using the Three-Electrode System
Published on: January 7, 2022
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A π-Conjugated Polyimide-Based High-Performance Aqueous Potassium-Ion Asymmetric Supercapacitor
Yaoyao Zhao1,2, Shicong Zhang3, Shumao Xu1
1State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai, 200050, China.
Macromolecular Rapid Communications
|March 8, 2022
Summary
Researchers developed stable, high-performance organic electrodes for aqueous asymmetric supercapacitors. Molecular engineering of polyimide with alkyl chains enhances energy storage capacity and cycle life in potassium-ion electrolytes.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Aqueous asymmetric supercapacitors offer sustainable high-power energy storage.
- Organic electrode materials provide sustainability and redox reactivity but face stability and power density challenges.
Purpose of the Study:
- To engineer π-conjugated polyimide-based organic electrodes with varying alkyl chain lengths for enhanced performance in aqueous potassium-ion electrolytes.
- To investigate the relationship between molecular structure and electrochemical properties for supercapacitor applications.
Main Methods:
- Fabrication of asymmetric supercapacitors using polyimide-based organic electrodes with different alkyl chain lengths.
- Electrochemical characterization including capacity measurements at various current densities and long-term cycling stability tests.
- Material characterization using electrochemical quartz crystal microbalance, ex-situ Fourier transformed infrared spectroscopy, and X-ray photoelectron spectroscopy.
Main Results:
- The supercapacitor demonstrated high capacities of 107 mAh g⁻¹ at 2 A g⁻¹ and 67 mAh g⁻¹ at 90 A g⁻¹.
- Exceptional cycling stability was achieved, retaining 65 mAh g⁻¹ (over 70% of initial performance) after 65,000 cycles.
- Molecular engineering with long alkyl chains improved stability by reducing π-conjugation and blocking active sites, leading to enhanced durability.
Conclusions:
- The study showcases a promising polyimide-based polymer with an extended π-conjugated system for high-performance asymmetric supercapacitors.
- Pseudocapacitance behavior was confirmed, originating from redox reactions involving potassium ions and hydrated potassium ions with the polyimide structure.
- Tailoring alkyl chain lengths in polyimide offers a viable strategy to balance redox activity and structural stability for advanced energy storage devices.
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