Directly Grown Multiwall Carbon Nanotube and Hydrothermal MnO2 Composite for High-Performance Supercapacitor Electrodes.

Li Li,Fei Xie,Changkun Dong,Weijin Qian,Lihui Chen

doi:10.3390/nano9050703

Abstract

MnO2–MWNT–Ni foam supercapacitor electrodes were developed based on directly grown multiwalled carbon nanotubes (MWNTs) and hydrothermal MnO2 nanostructures on Ni foam substrates. The electrodes demonstrated excellent electrochemical and battery properties. The charge transfer resistance dropped 88.8% compared with the electrode without MWNTs. A high specific capacitance of 1350.42 F·g−1 was reached at the current density of 6.5 A·g−1. The electrode exhibited a superior rate capability with 92.5% retention in 25,000 cycles. Direct MWNT growth benefits the supercapacitor application for low charge transfer resistance and strong MWNT–current collector binding.

Highlights

The supercapacitor, mainly the electrical double-layer capacitor (EDLC) and the pseudocapacitor, is of interest for quick charging/discharging capacity, high power density, and long cycle life [1,2]
Supercapacitor devices constructed upon carbon nanomaterials, including carbon nanotube (CNT) and graphene, have been widely investigated and have shown remarkable electrochemical properties [7,8,9,10]
Wei et al prepared a 3D nanostructure by growing carbon nanotubes between graphene layers, which exhibited good electrochemical properties with a specific capacitance of 385 F·g−1 [11]

Summary

Introduction

The supercapacitor, mainly the electrical double-layer capacitor (EDLC) and the pseudocapacitor, is of interest for quick charging/discharging capacity, high power density, and long cycle life [1,2]. Wei et al prepared a 3D nanostructure by growing carbon nanotubes between graphene layers, which exhibited good electrochemical properties with a specific capacitance of 385 F·g−1 [11]. Excellent cycle stability, and an environmentally friendly nature, MnO2 is typically employed as the active material to further improve the energy efficiency of CNT-based electrodes, and CNT–MnO2 composite electrodes have shown great advantages in pseudocapacitors [16,17,18,19,20].

Results

Conclusion