Flexible all solid-state niobium nitride//activated carbon lithium-ion hybrid capacitor with high volumetric power and energy densities

Debasish Mandal, Jong Yeob Jeong, Bal Sydulu Singu, Seojun Lee, Woo Jin Mun, Hansung Kim

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6 Citations (Scopus)


Flexible electrochemical energy storage devices are gaining considerable interest for use in smart portable flexible electronic devices. Herein, a (Niobium nitride) NbN// Activated carbon (AC) flexible (bendable and twistable) solid-state lithium-ion hybrid capacitor (LIHC) enabled by a thin graphite-layer-coated adhesive tape-based flexible current collector is reported. NbN is synthesized by a solvothermal treatment of the niobium pentachloride (NbCl5) precursor and a subsequent nitridation treatment of the intermediate solvothermal product. Microscopic, spectroscopic, and X-ray studies signify the formation of porous 2D nanoflake units with a cubic crystalline phase, which aggregate to form microspheres. The NbN displays a high specific capacity of 347.73 mAh g−1 at 0.2 A g−1 with excellent cyclic stability (98.1% capacity retention after 10,000 cycles). The outstanding cyclic stability is clarified by the analysis of electrochemical impedance spectroscopy (EIS). The designed highly flexible LIHC with a high electrode mass loading of 280 mg cm−3 possesses a high capacitance of 2597 mF cm−3 at a current density of 60 mA cm−3. The device displays a high-energy density of 3.25 mWh cm−3, high power density of 254.2 mW cm−3, and excellent cyclic stability at 133 mA cm−3 (97.7% capacity retention after 10,000 cycles). Therefore, the designed flexible LIHC can be utilized for the development of smart flexible electronic devices.

Original languageEnglish
Article number104031
JournalJournal of Energy Storage
Publication statusPublished - 2022 Apr

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation (NRF) grant funded by the Ministry of Science, ICT, and Future Planning ( NRF-2018M3A7B4071535 ), and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education ( NRF-2019R1A6A1A11055660 ).

Publisher Copyright:
© 2022 Elsevier Ltd

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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