Oxalic acid assisted rapid synthesis of mesoporous NiCo2O4 nanorods as electrode materials with higher energy density and cycle stability for high-performance asymmetric hybrid supercapacitor applications

Jiwan Acharya; Tae Hoon Ko; Min-Kang Seo; Myung-Seob Khil; Hak-Yong Kim; Byoung-Suhk Kim

doi:10.1016/j.jcis.2019.12.098

Oxalic acid assisted rapid synthesis of mesoporous NiCo₂O₄ nanorods as electrode materials with higher energy density and cycle stability for high-performance asymmetric hybrid supercapacitor applications

J Colloid Interface Sci. 2020 Mar 22:564:65-76. doi: 10.1016/j.jcis.2019.12.098. Epub 2019 Dec 24.

Authors

Jiwan Acharya¹, Tae Hoon Ko², Min-Kang Seo³, Myung-Seob Khil⁴, Hak-Yong Kim², Byoung-Suhk Kim⁵

Affiliations

¹ Department of BIN Convergence Technology, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
² Department of BIN Convergence Technology, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Department of Organic Materials & Fiber Engineering, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
³ Korea Institute of Carbon Convergence Technology, Jeonju 54852, Republic of Korea.
⁴ Department of Organic Materials & Fiber Engineering, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
⁵ Department of BIN Convergence Technology, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Department of Organic Materials & Fiber Engineering, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: kbsuhk@jbnu.ac.kr.

PMID: 31901835
DOI: 10.1016/j.jcis.2019.12.098

Abstract

In this study, mesoporous nickel cobaltite (NiCo₂O₄) nanorods as electrode materials for high-performance hybrid supercapacitor were fabricated onto Ni foam by a simple and cost effective oxalic acid (OA) assisted rapid co-precipitation method. The effects of different metal precursors (NCO-Nitrate, NCO-Chloride and NCO-Acetate) on the electrochemical capacitive properties were studied. FE-SEM analysis confirmed that all samples exhibited highly dense mesoporous NiCo₂O₄ nanorods vertically grown on the surface of Ni foam with excess accessible surfaces and unique sizes and morphologies. The resultant NiCo₂O₄ nanorod electrodes (for NCO-Nitrate, NCO-Chloride and NCO-Acetate) delivered the maximum specific capacitances of 790, 784, 776 F g^-1 at the current density of 1 A g^-1 with ultra-high capacitance retention of 82.27, 81.63 and 81.71% even at 20 A g^-1 and excellent cyclic stability of 84.25, 83.33 and 83.24% capacitance retention at 5 A g^-1 after 5000 cycles. The asymmetric supercapacitor (ASC) device was also sandwiched by using NCO-Nitrate as positive electrode and N-doped graphene hydrogel (NGH) as negative electrode. The fabricated ASC device delivered superior energy density (42.5 W h kg^-1) at high power density (746.34 W kg^-1) with excellent long cyclic stability (90% initial capacitance retention after 5000 cycles at 5 A g^-1).

Keywords: Cycle stability; Energy density; Mesoporous; Nanorod; Supercapacitor.