Higher-power supercapacitor electrodes based on mesoporous manganese oxide coating on vertically aligned carbon nanofibers

Abstract

A study on the development of high-power supercapacitor materials based on formation of thick mesoporous MnO2 shells on a highly conductive 3D template using vertically aligned carbon nanofibers (VACNFs). Coaxial manganese shells of 100 to 600 nm nominal thicknesses are sputter-coated on VACNFs and then electrochemically oxidized into rose-petal-like mesoporous MnO2 structure. Such a 3D MnO2/VACNF hybrid architecture provides enhanced ion diffusion throughout the whole MnO2 shell and yields excellent current collection capability through the VACNF electrode. These two effects collectively enable faster electrochemical reactions during charge-discharge of MnO2 in 1 M Na2SO4. Thick MnO2 shells (up to 200 nm in radial thickness) can be employed, giving a specific capacitance up to 437 F g(-1). More importantly, supercapacitors employing such a 3D MnO2/VACNF hybrid electrode illustrate more than one order of magnitude higher specific power than the state-of-the-art ones based on other MnO2 structures, reaching ∼240 kW kg(-1), while maintaining a comparable specific energy in the range of 1 to 10 Wh kg(-1). This hybrid approach demonstrates the potential of 3D core-shell architectures for high-power energy storage devices.

A facile one-step approach to hierarchically assembled core–shell-like MnO2@MnO2 nanoarchitectures on carbon fibers: An efficient and flexible electrode material to enhance energy storage

“…), different growth methods have been investigated [45][46][47][48]. Among these methods, electrochemical deposition (ED) is a facile approach because it is quick, operates at low-temperature, and has a simple experimental setup.…”

Hierarchically Porous N-Doped Carbon Nanosheets Derived From Grapefruit Peels for High-Performance Supercapacitors

“…Supercapacitors (SCs), also known as ultracapacitors or electrochemical capacitors, have been identified as one of the most promising energy‐storage devices due to their high power density, ultralong cycling life, short charging time and good reversibility . According to their different charge‐storage mechanisms, supercapacitors can be classified into two types: pseudocapacitors and electrical double‐layer capacitors (EDLCs) . Pseudocapacitors store electrical energy by redox reactions, electrosorption and intercalation processes .…”

Symmetric/Asymmetric Supercapacitor Based on the Perovskite-type Lanthanum Cobaltate Nanofibers with Sr-substitution.

“…In this sense, improving the energy density of TMOs, while maintaining their high power capability is an alternative solution to meet development of supercapacitors [13,14] . As the energy density is related by the operating potential window (V) and the specific capacitance (C), we should increase both V and C to enhance the energy density [15][16][17] .…”