Hierarchical Manganese–Iron-Layered Double Hydroxide Nanosheets for Asymmetric Supercapacitors

Dipali S. Patil,Sachin A. Pawar,Hyo Jin Kim,Jae Cheol Shin

doi:10.3390/en13184616

Dipali S. Patil, Sachin A. Pawar + Show 2 more

Open Access

https://doi.org/10.3390/en13184616

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Abstract

This work presents a synthesis of hierarchical manganese–iron-layered double hydroxide (MnFe-LDH) nanostructured electrodes using the hydrothermal synthesis route by varying the reaction time for electrochemical energy storage applications. The electrochemical behavior of the MnFe-LDH electrodes synthesized at different reaction times was analyzed in a three-electrode cell configuration using 2 M KOH electrolyte. The uniform and well-organized MnFe-LDH nanosheet electrode (MnFe-12h) showed the maximum areal capacitance of 2013 mFcm−2 at a 5 mVs−1 scan rate, and 1886 mFcm−2 at a 25 mA applied current. Furthermore, the electrochemical behavior of MnFe-12h was examined by assembling an asymmetric cell device using activated carbon (AC) as a negative electrode and MnFe-12h as a positive electrode and it was tested in a wide voltage window range of 0.0 to 1.6 V. This asymmetric cell device achieved an appropriate energy density of 44.9 µW h cm−2 (55.01 W h kg−1), with a power density of 16 mW cm−2 (5000 W kg−1) at an applied current of 10 mA, and had a long-term cycling stability (93% capacitance retention after 5000 cycles) within the 1.6 V operating voltage window.

Highlights

The current global situation due to climate change demands green energy alternatives such as renewable energies in order to preserve our ecosystem
The probable chemical reactions happening during the formation of MnFe-hydroxide through hydrothermal treatment can be signified by the following reactions: CO(NH2 )2 + H2 O → 2NH3 + CO2 (1)
We modified the morphological features of MnFe-Layered double hydroxides (LDHs) using the hydrothermal method and examined in detail its supercapacitive electrochemical performance

Summary

Introduction

The current global situation due to climate change demands green energy alternatives such as renewable energies in order to preserve our ecosystem. Fabricated Co-Ni LDH using the electrophoretic deposition technique, which produced a specific capacitance of 1931 Fg−1 [13]. An asymmetric supercapacitor was fabricated by Li et al based on a (Ni,Co)Se2/NiCo-LDH core-shell with a specific capacitance of 1224 Fg−1 [16]. Despite the fact that many LDH composites are involved in supercapacitor studies, MnFe-LDH is a versatile electrode material for pseudocapacitor studies as it can replace the carbon-based supercapacitor that is capable of producing a high energy density. An asymmetric cell device using activated carbon as a negative electrode and MnFe-12h as a positive electrode was assembled and tested in a wide voltage window range of 0.0 to 1.6 V This asymmetric cell device achieved an appropriate energy density of 44.9 μW h cm−2 (50.01 W h kg−1 ), with a power density of. Capacitance retention after 5000 cycles) within the 1.6 V operating voltage window

Experimental Details

M KOHand between assembled by inserting filterassembled paper soaked

Results and Discussion

Galvanostatic

Conclusions