Carbon-Nanotubes@MnO2-Nanosheets Core-Shell Arrays on Carbon Cloth for
High Volumetric Capacitance Flexible Supercapacitors
Abstract
Supercapacitors hold great promise as energy storage devices due to
their rapid charge-discharge rates and exceptional durability. However,
their low energy density has constrained their practical applications.
In this study, we synthesize carbon-nanotubes@MnO2-nanosheets core-shell
nanotube arrays on carbon cloth to enhance the volumetric capacitance of
supercapacitors. Our method utilizes radially grown ZnO nanowires as
sacrificial supports to fabricate carbon-nanotube-supported MnO2
structures. The resulting electrode exhibits a high specific capacitance
of 0.52 F cm⁻² at 2 mV s⁻¹ and demonstrates excellent rate performance,
maintaining a capacitance of 0.25 F cm⁻² at a high scan rate of 100 mV
s⁻¹. The asymmetric solid-state supercapacitor, constructed using this
composite and paired with a carbon electrode, displays outstanding
electrochemical performance, including a voltage window of up to 1.8 V,
a high volumetric energy density of 2.85 mWh cm⁻³, and a power density
of 453.8 mW cm⁻³. These findings provide valuable insights for the
development of next-generation energy storage devices, capable of
meeting the growing demands for portable and flexible electronics.