Localized Electron Density Regulation Effect for Promoting Solid-Liquid Ion Adsorption to Enhance Areal Capacitance...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Flexible microelectronic systems require high-energy-output planar micro-supercapacitors (MSCs).
• Current MSCs face limitations in energy density due to confined spaces and interfacial ion adsorption.
• Surface modification strategies are crucial for enhancing MSC performance.

Purpose of the Study:

• To regulate localized electron density on MSC electrodes using graphene quantum dots (GQDs).
• To investigate the impact of GQDs on ion electrostatic adsorption and energy density.
• To explore the potential of this strategy for flexible microelectronic applications.

Main Methods:

• Introducing graphene quantum dots (GQDs) onto electrode surfaces.
• Investigating local electronic structure via topological analysis of electron localization function (ELF) and electron density.
• Fabricating and testing all-carbon-based symmetric MSCs, Zn-ion hybrid MSCs, and ion-gel electrolyte MSCs.

Main Results:

• GQDs enhance local field intensity, promoting ion adsorption and improving energy density.
• Edge electron density distribution in GQDs reinforces electrical double-layer capacitance (EDLC) and pseudocapacitance.
• All-carbon symmetric MSCs achieved ultra-high areal capacitance (21.78 mF cm⁻²) and excellent cycle stability (86.74% retention after 25,000 cycles).
• The strategy was successfully applied to polyvalent and non-metallic ion systems.

Conclusions:

• Surface local charge regulation using GQDs is an effective strategy to significantly improve MSC energy density and stability.
• This approach offers a pathway for developing high-performance flexible microelectronic devices.
• The method shows versatility for various ion systems and potential applications in timing and environmental monitoring.