Mesoporous Gold Electrodes for High-Areal-Capacitance Supercapacitors
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Solution Overview
Problem
Existing micro-supercapacitors suffer from low energy density and limited capacitance per unit area, making them inadequate for powering wireless sensor nodes and microelectronic devices, and there is a need for a method to fabricate porous electrodes suitable for micro-supercapacitors.
Innovation Solution
A method involving dynamic hydrogen bubble templating is used to create a porous gold electrode, followed by electrodeposition of hydrous ruthenium oxide, resulting in a porous gold/RuO2·xH2O structure with high electrochemical active surface area and interconnected pores, enhancing capacitance and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional micro-supercapacitor structures are used, then power performance is maintained, but energy density remains low
Solution Approach 1:
The patent employs a porous gold substrate with controlled pore sizes (2-20 μm) and high porosity (60-80%) to dramatically increase the electrochemically active surface area. This porous structure allows RuO2 capacitive material to deposit throughout the three-dimensional network, achieving areal capacitances exceeding 3 F/cm² while maintaining excellent power performance through the conductive gold framework that facilitates ion transport.
Solution Approach 2:
The invention transitions from traditional planar two-dimensional electrode structures to a three-dimensional porous network architecture. The vertical penetration of RuO2 into the porous gold substrate creates a volumetric energy storage structure, increasing the effective surface area by factors of 10-100 times compared to flat electrodes, thereby simultaneously improving energy density and maintaining power performance.
2Use of energy by moving object
If Li-ion micro-batteries are used, then energy density is achieved, but lifetime and maintainability become problematic
Solution Approach 1:
The patent changes the fundamental operating parameters by using a porous gold substrate with controlled pore size distribution (2-20 μm) and optimized RuO2 deposition conditions. These parameter changes enable the system to achieve battery-like energy density (1 J/cm²) while maintaining the inherent reliability advantages of supercapacitors, including long cycle life and maintenance-free operation.
3Quantity of substance
If higher areal capacitance is achieved through porous structures, then manufacturing complexity increases
Solution Approach 1:
The porous gold substrate serves a dual function: it provides the conductive framework and simultaneously acts as the template that defines the pore structure. The RuO2 capacitive material self-assembles within the porous network through electrochemical deposition, eliminating the need for separate template fabrication and material deposition steps. This self-organizing approach achieves high areal capacitance while simplifying the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The porous gold/RuO2·xH2O electrode achieves unprecedented areal capacitance of 3.25 F/cm² and energy density of 1 J/cm², surpassing state-of-the-art micro-batteries and micro-supercapacitors, suitable for all-solid-state supercapacitors and integration on silicon chips.
Implementation Method 1
dynamic hydrogen bubble templating is used to create a porous gold electrode
Implementation Method 2
electrodeposition of hydrous ruthenium oxide
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
A method comprising forming a mesoporous conductive layer and depositing a capacitive material within pores of the mesoporous conductive layer through a thickness of the mesoporous conductive layer. The mesoporous conductive layer may be formed by physical deposition or electrodeposition of gold, platinum or titanium, and the capacitive material may be Ru, Ni, Fe, Co, Ir or Mn, yielding a mesoporous electrode. Two such electrodes may be assembled using a solid electrolyte, yielding an all-solid-state supercapacitor. The mesoporous conductive layer may be deposited on a substrate provided with an interdigitated electrode resin mask, and the resin mask removed after depositing the capacitive material within pores of the mesoporous conductive layer, to yield interdigitated electrodes.