Synergistic effects of nanoarchitecture and oxygen vacancy in nickel molybdate hollow sphere towards a high-performance hybrid supercapacitor

Periyasamy Sivakumar, C. Justin Raj, Jeong Won Park, Hyun Jung

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The facile design and fabrication of nanoarchitectured binary transition metal oxide electrode materials are essentially required for the advancement of high-performance supercapacitors (SCs). Herein, we prepared an oxygen-vacant NiMoO4 (Ov-NiMoO4) hollow sphere via a simple hydrothermal approach and subsequent heat treatment under an argon atmosphere. In particular, the oxygen vacancy is confirmed by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Raman, and differential reflectance spectroscopy (DRS) UV-Vis spectra studies. Furthermore, the generation of the oxygen vacancy could enhance the electrical conductivity and improve Faradaic redox sites. Significantly, the Ov-NiMoO4 hollow sphere depicts a larger specific capacity (Csp) of 496 mA h g−1 at 1 A g−1 than the bare-NiMoO4 (b-NiMoO4; 279 mA h g−1) thermally treated under air. Furthermore, the hybrid SC (HSC) is fabricated based on the Ov-NiMoO4//activated carbon, revealing a high specific capacitance (Cs) of 120 F g−1 and providing a large energy density (ED) of 37.49 W h kg−1 and power density (PD) of 36.61 kW kg−1. Moreover, the HSC shows considerable cyclic stability of ~91.14% over 20 000 cycles. The results divulge that the poor crystallinity and the introduction of oxygen vacancies play a vital role in enhancing the charge-storage capability of the materials.

Original languageEnglish
Pages (from-to)21516-21526
Number of pages11
JournalInternational Journal of Energy Research
Issue number15
StatePublished - Dec 2021
Externally publishedYes

Bibliographical note

Funding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) of Korea, South Korea, funded by the Ministry of Education (Grant No. NRF‐2016R1D1A1B01009640).

Funding Information:
Ministry of Education, National Research Foundation of Korea, Grant/Award Number: NRF‐2016R1D1A1B01009640 Funding information

Publisher Copyright:
© 2021 John Wiley & Sons Ltd.


  • NiMoO
  • energy storage
  • hollow sphere
  • hybrid supercapacitor
  • oxygen vacancy


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