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Towards High-Energy and Anti-Self-Discharge Zn-Ion Hybrid Supercapacitors with New Understanding of the Electrochemistry.
- Source :
- Nano-Micro Letters; Jan2021, Vol. 13 Issue 1, p1-16, 16p
- Publication Year :
- 2021
-
Abstract
- Highlights: A surface engineering strategy was proposed to design hierarchically porous structure on fibrous carbon cathodes with O/N heteroatom functional groups. High-energy and anti-self-discharge Zn-ion hybrid supercapacitors (ZHSs) were realized. ZHS electrochemistry was investigated and new insights were provided.Aqueous Zn-ion hybrid supercapacitors (ZHSs) are increasingly being studied as a novel electrochemical energy storage system with prominent electrochemical performance, high safety and low cost. Herein, high-energy and anti-self-discharge ZHSs are realized based on the fibrous carbon cathodes with hierarchically porous surface and O/N heteroatom functional groups. Hierarchically porous surface of the fabricated free-standing fibrous carbon cathodes not only provides abundant active sites for divalent ion storage, but also optimizes ion transport kinetics. Consequently, the cathodes show a high gravimetric capacity of 156 mAh g<superscript>−1</superscript>, superior rate capability (79 mAh g<superscript>−1</superscript> with a very short charge/discharge time of 14 s) and exceptional cycling stability. Meanwhile, hierarchical pore structure and suitable surface functional groups of the cathodes endow ZHSs with a high energy density of 127 Wh kg<superscript>−1</superscript>, a high power density of 15.3 kW kg<superscript>−1</superscript> and good anti-self-discharge performance. Mechanism investigation reveals that ZHS electrochemistry involves cation adsorption/desorption and Zn<subscript>4</subscript>SO<subscript>4</subscript>(OH)<subscript>6</subscript>·5H<subscript>2</subscript>O formation/dissolution at low voltage and anion adsorption/desorption at high voltage on carbon cathodes. The roles of these reactions in energy storage of ZHSs are elucidated. This work not only paves a way for high-performance cathode materials of ZHSs, but also provides a deeper understanding of ZHS electrochemistry. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 23116706
- Volume :
- 13
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Nano-Micro Letters
- Publication Type :
- Academic Journal
- Accession number :
- 149387420
- Full Text :
- https://doi.org/10.1007/s40820-021-00625-3