In this work, manganese dioxide (MnO2) nanosheets
in
situ loaded on a high-purity graphite flake (GF) were prepared by
one-step hydrothermal deposition. It was found that the specific capacitance
value of a single MnO2/GF electrode was 882 F/g at a current
density of 1.0 A/g in a KOH electrolyte, and the specific capacitance
retention of the MnO2/GF electrode can reach about 90.1%
after 5000 charge–discharge cycles at a current density of
10 A/g. Furthermore, a MnO2/GF∥MnO2/GF
symmetric supercapacitor device was fabricated with two pieces of
MnO2/GF electrodes and ordinary filter paper with a 1 M
KOH/PVA gel electrolyte as a separator. The single symmetric device
displayed a high energy density of 64.2 Wh/kg at a power density of
400 W/kg within an applied voltage of 1.6 V, and this value was superior
to those of previously reported MnO2-based systems. A tandem
device consisting of a five-series tandem device (the applied voltage
of a single device was 0.7 V) and a three-series tandem device (the
applied voltage of a single device was 1.6 V) was prepared to drive
a red light-emitting diode (LED). These findings open up application
prospects for MnO2-based composite electrode materials
for high-performance supercapacitors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.