Zinc-Based Metal–Organic Frameworks for High-Performance Supercapacitor Electrodes: Mechanism Underlying Pore Generation

Shigeyuki Umezawa, Takashi Douura, Koji Yoshikawa, Daisuke Tanaka, Vlad Stolojan, S. Ravi P. Silva, Mika Yoneda, Kazuma Gotoh, Yasuhiko Hayashi

Research output: Contribution to journalArticlepeer-review

Abstract

Heat treatment of metal–organic frameworks (MOFs) has provided a wide variety of functional carbons coordinated with metal compounds. In this study, two kinds of zinc-based MOF (ZMOF), C16H10O4Zn (ZMOF1) and C8H4O4Zn (ZMOF2), were prepared. ZMOF1 and ZMOF2 were carbonized at 1000 °C, forming CZMOF1 and CZMOF2, respectively. The specific surface area (SBET) of CZMOF2 was ~2700 m2 g−1, much higher than that of CZMOF1 (~1300 m2 g−1). A supercapacitor electrode based on CZMOF2 achieved specific capacitances of 360, 278, and 221 F g−1 at 50, 250, and 1000 mA g−1 in an aqueous electrolyte (H2SO4), respectively, the highest values reported to date for ZMOF-derived electrodes under identical conditions. The practical applicability of the CZMOF-based supercapacitor was verified in non-aqueous electrolytes. The initial capacitance retention was 78% after 100 000 charge/discharge cycles at 10 A g−1. Crucially, the high capacitance of CZMOF2 arises from pore generation during carbonization. Below 1000 °C, pore generation is dominated by the Zn/C ratio of ZMOFs, as carbon atoms reduce the zinc oxides formed during carbonization. Above 1000 °C, a high O/C ratio becomes essential for pore generation because the oxygen functional groups are pyrolyzed. These findings will provide insightful information for other metal-based MOF-derived multifunctional carbons.

Original languageEnglish
JournalEnergy and Environmental Materials
DOIs
Publication statusAccepted/In press - 2022

Keywords

  • metal–organic frameworks
  • pore generation
  • porous carbons
  • supercapacitor
  • zinc oxides

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy (miscellaneous)
  • Materials Science(all)
  • Waste Management and Disposal
  • Water Science and Technology
  • Environmental Science (miscellaneous)

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