In-Situ Synthesis of Heterostructured Carbon-Coated Co/MnO Nanowire Arrays for High-Performance Anodes in Asymmetric Supercapacitors.

Guoqing Chen,Xuming Zhang,Jijiang Fu,Biao Gao,Chaoran Pi,Paul K Chu,Yang Zheng,Hao Song,Yuanhang Ma

doi:10.3390/molecules25143218

Abstract

Structural design is often investigated to decrease the electron transfer depletion in/on the pseudocapacitive electrode for excellent capacitance performance. However, a simple way to improve the internal and external electron transfer efficiency is still challenging. In this work, we prepared a novel structure composed of cobalt (Co) nanoparticles (NPs) embedded MnO nanowires (NWs) with an N-doped carbon (NC) coating on carbon cloth (CC) by in situ thermal treatment of polydopamine (PDA) coated MnCo2O4.5 NWs in an inert atmosphere. The PDA coating was carbonized into the NC shell and simultaneously reduced the MnCo2O4.5 to Co NPs and MnO NWs, which greatly improve the surface and internal electron transfer ability on/in MnO boding well supercapacitive properties. The hybrid electrode shows a high specific capacitance of 747 F g−1 at 1 A g−1 and good cycling stability with 93% capacitance retention after 5,000 cycles at 10 A g−1. By coupling with vanadium nitride with an N-doped carbon coating (VN@NC) negative electrode, the asymmetric supercapacitor delivers a high energy density of 48.15 Wh kg−1 for a power density of 0.96 kW kg−1 as well as outstanding cycling performance with 82% retention after 2000 cycles at 10 A g−1. The electrode design and synthesis suggests large potential in the production of high-performance energy storage devices.

Highlights

Growing concerns about environmental pollution arising from consumption of fossil fuels have spurred the development of green and sustainable energy and efficient energy storage devices for portable electronics and electric vehicles are in high demand [1,2]
More efficient structures must be designed to make it commercial viable [21,22,23,24]. Such as core-shell MnO@N-rich carbon nanosheets as the positive supercapacitor electrode with a capacitance of 570 F g−1 at 2 A g−1 as well as capacitance retention of 99% for 6000 cycles [18], hierarchical porous and hollow core-shell MnO2 @C microspheres with a specific capacitance of 280 F g−1 at a current density of 0.1 A g−1 [25], amorphous MnO2 decorated TiC/C core/shell nanofiber electrode with a high specific discharge capacity of 645 F g−1 at 1 A g−1 together with 99% capacity retention after
The morphology and crystal structure of the samples were characterized by field-emission scanning electron microscopy (FE-SEM, FEI Nova 450 Nano), transmission electron microscopy (TEM, JEOL 2010), X-ray diffraction (XRD, Philipa X’Pert Pro), and X-ray photoelectron spectroscopy (XPS, PHI-5000 V)

Summary

Introduction

Growing concerns about environmental pollution arising from consumption of fossil fuels have spurred the development of green and sustainable energy and efficient energy storage devices for portable electronics and electric vehicles are in high demand [1,2]. More efficient structures must be designed to make it commercial viable [21,22,23,24] Such as core-shell MnO@N-rich carbon nanosheets as the positive supercapacitor electrode with a capacitance of 570 F g−1 at 2 A g−1 as well as capacitance retention of 99% for 6000 cycles [18], hierarchical porous and hollow core-shell MnO2 @C microspheres with a specific capacitance of 280 F g−1 at a current density of 0.1 A g−1 [25], amorphous MnO2 decorated TiC/C core/shell nanofiber electrode with a high specific discharge capacity of 645 F g−1 at 1 A g−1 together with 99% capacity retention after. Metal NPs incorporated into TMOs have been reported to enhance capacitive performance by reducing the electron transfer depletion, such as Ag-Co3 O4 [28], Au-MnO2 [29], and Au-NiO [30].

Experimental Details

Materials Characterization

Electrochemical Assessment

Preparation of Asymmetric Supercapacitor

Results and Discussion

Conclusions