Insights into the interfacial nanostructuring of NiCo2S4 and their electrochemical activity for ultra-high capacity all-solid-state flexible asymmetric supercapacitors

Vijay S Kumbhar; Nilesh R Chodankar; Kiyoung Lee; Do-Heyoung Kim

doi:10.1016/j.jcis.2019.08.096

Insights into the interfacial nanostructuring of NiCo₂S₄ and their electrochemical activity for ultra-high capacity all-solid-state flexible asymmetric supercapacitors

J Colloid Interface Sci. 2019 Dec 1:557:423-437. doi: 10.1016/j.jcis.2019.08.096. Epub 2019 Aug 29.

Authors

Vijay S Kumbhar¹, Nilesh R Chodankar², Kiyoung Lee³, Do-Heyoung Kim⁴

Affiliations

¹ School of Chemical Engineering, Chonnam National University, Gwangju 500-757, South Korea; School of Nano & Materials Science and Engineering, Kyungpook National University, 2559 Gyeongsang-daero, Sangju, Gyeongbuk, South Korea.
² Department of Energy and Materials Engineering, Dongguk University, Seoul 04620, South Korea.
³ School of Nano & Materials Science and Engineering, Kyungpook National University, 2559 Gyeongsang-daero, Sangju, Gyeongbuk, South Korea.
⁴ School of Chemical Engineering, Chonnam National University, Gwangju 500-757, South Korea. Electronic address: kdhh@chonnam.ac.kr.

PMID: 31539839
DOI: 10.1016/j.jcis.2019.08.096

Abstract

Ternary metal sulfide based nanostructured materials are promising for commercialization of the electrochemical energy storage devices. Herein, three different NiCo₂S₄ nanostructures (nanoflakes, nanosheets, and nanoparticles) were fabricated by electrodeposition. Of these, nanosheets consisting of interconnected nanoparticles formed a highly porous network for supercapacitive energy storage. The electrochemical properties of each electrode were studied in detail and it was observed that the self-supported NiCo₂S₄ nanosheets possess a highest specific capacity of 590 mA h g^-1 (2655 F g^-1) at 0.25 A g^-1 current density and cycling stability of 88.7% after 5000 charge-discharge cycles. This excellent behavior is attributed to several factors of the electrode such as high electrochemical active sites and ability of a nanostructure to withstand under high strain and accommodate large number of electrolyte ions during charge-discharge. The electrochemical storage properties of the NiCo₂S₄ nanosheets were further explored by fabricating battery-like solid-state asymmetric supercapacitor with activated carbon that delivered an ultra-high specific energy and power of 69.7 Wh kg^-1 and 8 kW kg^-1, respectively. These outcomes indicate that the novel nanostructured NiCo₂S₄ network has great potential for the development of energy storage devices.

Keywords: Battery-like supercapacitor; Electrodeposition; NiCo(2)S(4) nanostructures; Specific capacity; Specific energy.