Sheet-like ZnCo2O4 microspheres and pomelo peel waste-derived activated carbon for high performance solid state asymmetric supercapacitors

Kiran Kumar Reddy Reddygunta, Lidija Šiller, Aruna Ivaturi

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
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Abstract

A novel asymmetric supercapacitor based on zinc cobalt oxide (ZnCo 2O 4) as a positive electrode and pomelo peel-based activated carbon (PPAC-4) as a negative electrode was fabricated. ZnCo 2O 4 was synthesized using hydrothermal method and shows a distinct sheet-like structure clubbed together to form microspheres. PPAC-4 was synthesized via the chemical activation of pomelo peel hydrochar using KHCO 3 as the activation agent. The as-prepared ZnCo 2O 4 microspheres displayed maximum specific capacitance of 422 F g −1 at an applied current density of 1 A g −1, whereas PPAC-4 demonstrated a capacitance of 356 F g −1 at a current density of 1 A g −1. Moreover, the novel ZnCo 2O 4//PPAC-4 asymmetric solid-state supercapacitor with hydroxyethyl cellulose/potassium hydroxide (HEC/KOH) gel electrolyte displayed maximum operating voltage of 1.6 V with a superior energy density of 29.8 W h kg −1 at a power density of 796.3 W kg −1. Besides, a long-term cycling stability of 83% was achieved after 10 000 charge/discharge cycles, indicating its promise for future energy storage applications.

Original languageEnglish
Pages (from-to)2751-2761
Number of pages11
JournalSustainable Energy and Fuels
Volume8
Issue number12
Early online date17 May 2024
DOIs
Publication statusPublished - 21 Jun 2024

Funding

AI gratefully acknowledges Scottish Funding Council (SFC) Global Challenges Research Fund (GCRF) and Strathclyde Centre for Doctoral Training (SCDT), Centre for Interdisciplinary Sustainable Practices of Research in Energy (C-INSPRE), for co-funding Kiran’s studentship and this project. She also gratefully acknowledges UK Research and Innovation (UKRI), Engineering and Physical Sciences Research Council (EPSRC) for the Fellowship grant (EP/P011500/1). LŠ would like to thank Engineering and Physical Sciences Research Council (EPSRC) UK, for NEXUS facility at Newcastle University (NS/A000015/1).

Keywords

  • supercapacitor
  • energy storage
  • food waste

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