A high performance flexible all solid state supercapacitor based on the MnO2 sphere coated macro/mesoporous Ni/C...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state supercapacitors face limitations due to high contact resistance, low ionic conductivity, and dense electrode structures.
• Manganese dioxide (MnO2) shows promise as an active material but is hindered by these challenges.

Purpose of the Study:

• To develop a novel electrode structure for solid-state supercapacitors to overcome existing limitations.
• To enhance the capacitance and energy density of MnO2-based supercapacitors.

Main Methods:

• Fabrication of a ternary electrode system using hierarchical MnO2 spheres, macroporous Ni foam, and an ordered mesoporous carbon (OMC) membrane.
• Utilizing butyl-3-methylimidazolium chloride (BMIMCl) modified gels as the ionic conducting electrolyte.
• Characterization of electrochemical performance, including capacitance, energy density, power density, and cycling stability.

Main Results:

• Achieved 88% utilization efficiency of MnO2, resulting in a high volumetric capacitance of 81 F cm⁻³.
• Demonstrated exceptional volumetric energy (6.6 Wh L⁻¹) and power density (549 W L⁻¹).
• Exhibited excellent cycling stability with only an 8.5% capacity loss after 6000 cycles, even under twisting conditions.

Conclusions:

• The novel electrode design effectively overcomes the energy bottleneck in MnO2-based solid-state supercapacitors.
• This work highlights the potential of macro/mesoporous materials in developing high-performance flexible energy storage devices.