Ultrathin Supercapacitor Electrode Sheet for High Energy Retention
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Solution Overview
Problem
Existing supercapacitors, particularly ultrathin ones, face challenges in achieving miniaturization, high specific energy, and long duration time due to their large size, low capacitance, and high self-discharging rates, limiting their application in thin terminal products.
Innovation Solution
A positive-electrode sheet for capacitors is developed, comprising a carbon electrode material with a high specific surface area and a lithium-containing compound, combined with a conductive agent and binder, forming an electric double-layer structure, along with a single-layer laminated design for the ultrathin supercapacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a winding structure is used for supercapacitor, then the manufacturing process is established, but the size becomes relatively large and ultrathin design is limited
Solution Approach 1:
The supercapacitor is divided into multiple thin electrode sheets (positive and negative electrodes with separators) that are stacked in sequence. Each sheet is processed independently through coating, drying, and pressing operations, allowing for precise control of individual component thickness while achieving ultrathin overall device dimensions through the segmented layered structure.
2Volume of moving object
If the supercapacitor size is reduced, then miniaturization is achieved, but the capacitance becomes low and duration time is reduced
Solution Approach 1:
The electrode sheets utilize porous carbon materials as the active substance, which provide extremely high specific surface area (1400-2000 m2/g) within a compact volume. This porous structure enables the accumulation of large amounts of electrolyte and formation of electric double-layer capacitance, achieving high capacitance and long duration time despite the ultrathin overall device size.
3Volume of moving object
If the supercapacitor size is reduced, then miniaturization is achieved, but the specific energy becomes low and self-discharging increases
Solution Approach 1:
The electrode sheets employ composite material composition including porous carbon active substance (60-90 wt%), conductive agent (0.5-5 wt%), and binder (1-10 wt%). This composite structure combines the high energy density of porous carbon materials with the electrical conductivity of conductive agents and the structural integrity of binders, achieving high specific energy in the ultrathin configuration while reducing self-discharging through optimized material composition.
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 solution enhances specific energy, reduces self-discharging, and ensures a long duration time, enabling miniaturization and improved reliability, safety, and ease of manufacturing for ultrathin supercapacitors suitable for thin terminal products.
Implementation Method 1
The carbon electrode material is added to the positive-electrode active material to form a single sheet structure to construct an electric double-layer structure for the supercapacitor
Implementation Method 2
The porous carbon electrode material has a specific surface area of 1400 m2/g to 2000 m2/g, which provides extensive surface area for ion adsorption and enhances the capacitance of the supercapacitor
Data Source
AI summary
A positive-electrode sheet for a capacitor includes a first active substance layer. The first active substance layer comprises a positive-electrode active material, a carbon electrode material, a positive-electrode conductive agent, and a positive-electrode binder. A method of manufacturing the positive-electrode sheet for the capacitor includes: mixing the positive-electrode active material, the carbon electrode material, the positive-electrode conductive agent and the positive-electrode binder to obtain a positive-electrode material; and processing and molding the positive-electrode material to obtain the first active substance layer. An ultrathin supercapacitor includes a case and an upper cover body that is insulated from and connected to the case.