Lithium ferrite (α-LiFe5O8) nanorod based battery-type asymmetric supercapacitor with NiO nanoflakes as the counter electrode?

New Journal of Chemistry Pub Date: 2019-09-16 DOI: 10.1039/C9NJ03774H

Abstract

Over the past few decades, most of the work on electrochemical charge storage devices has been focused on the development of positive electrodes in the field of supercapacitors. Besides, the development of negative electrodes is very rare and also they deliver poor specific capacitance and hence more attention should be paid to the development of the same. The present study deals with the fabrication of a battery-type asymmetric supercapacitor (α-LiFe5O8//NiO) and examination of its electrochemical performance. Herein, a facile and cost-effective route was adopted to prepare α-LiFe5O8 nanorods and they demonstrate battery-type Faradaic behaviour with a Fe3 ? Fe0 quasi-conversion reaction in a negative potential window. In a three electrode cell, they exhibit a specific capacity of 999 C g?1 at 2 A g?1. Similarly, the nanoflakes of NiO electrodes exhibit Faradaic behaviour in a positive potential window, which results in an excellent specific capacity of 477 C g?1 at a specific current of 2 A g?1. The fabricated asymmetric supercapacitor device indicates a Faradaic nature of the energy storage process and it provides a specific capacity of 134 C g?1 at a specific current of 4 A g?1. Moreover, the asymmetric cell delivers a specific energy of 30 W h kg?1 at a specific power of 621 W kg?1. These appreciable features of the asymmetric supercapacitor are explained on the basis of the synergy between NiO and α-LiFe5O8.

Graphical abstract: Lithium ferrite (α-LiFe5O8) nanorod based battery-type asymmetric supercapacitor with NiO nanoflakes as the counter electrode
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