AUTHOR=Liang Wenyu , Zhitomirsky Igor 

TITLE=Zn-Fe Double Hydroxide-Carbon Nanotube Anodes for Asymmetric Supercapacitors

JOURNAL=Frontiers in Materials

VOLUME=Volume 7 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2020.00137

DOI=10.3389/fmats.2020.00137

ISSN=2296-8016

ABSTRACT=Zn-Fe double hydroxide (Zn-Fe-DH) – multiwalled carbon nanotube (MWCNT) composite has been developed for energy storage in negative electrodes of asymmetric supercapacitors. A conceptually new approach is based on the use of celestine blue (CB) dye as a multifunctional additive. We discovered that CB acted as a dispersant for Zn-Fe-DH and MWCNT, facilitated their mixing and interfacial charge transfer. The electrodes showed a capacitance of 5.2 F cm-2 in 0.5 M Na2SO4 electrolyte in a voltage window of -1.0 - -0.2 V vs saturated calomel electrode and good cyclic stability. A new asymmetric device has been developed, containing Zn-Fe-DH-MWCNT negative electrodes and polypyrrole coated MWCNT positive electrodes. Good capacitive behaviour of cathode and anode materials was achieved at high active mass of 40 mg cm-2 in partially overlapping potential windows. The device showed promising performance in a voltage window of 1.6 V. The capacitance of 2.2 F cm-2 was obtained at a scan rate of 2 mV s-1.