Carbon Particles with Controlled Oxygen Content for Supercapacitors
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Solution Overview
Problem
The capacitive performance of carbon spheres in electrochemical applications is limited, restricting the energy density of batteries, and existing methods for activating carbon particles often result in high oxygen content, leading to self-discharge and reduced conductivity.
Innovation Solution
A method of preparing carbon particles through hydrothermal synthesis using carbohydrate precursors, followed by chemical and physical activation, to achieve a composition with controlled oxygen content between 5% to 30%, enhancing their capacitive performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon spheres are activated with potassium hydroxide to improve capacitive performance, then the energy density of batteries is improved, but the oxygen content increases leading to self-discharge and reduced conductivity
Solution Approach 1:
The patent applies parameter changes by controlling the oxygen content in carbon particles to fall within a specific range of 5-30% by weight. This optimized oxygen level balances capacitive performance enhancement while preventing excessive oxygen from causing self-discharge and conductivity reduction. The activation process parameters are adjusted to achieve this precise oxygen content control.
Solution Approach 2:
The patent creates a composite carbon particle structure that combines activated carbon with controlled oxygen content. This composite approach integrates the high capacitive performance of activated carbon while incorporating oxygen at optimized levels to maintain conductivity and prevent self-discharge, effectively combining benefits while mitigating drawbacks.
2Reliability
If carbon particles are highly activated to increase surface area and capacitance, then the gravimetric capacitance improves, but the volumetric capacitance decreases due to increased porosity
Solution Approach 1:
The patent applies local quality by creating carbon particles with heterogeneous pore distribution and varying wall densities. Different regions of the carbon particles have different porosity levels, allowing high gravimetric capacitance in highly porous regions while maintaining sufficient structural density in other regions to preserve volumetric capacitance. This localized variation in structure optimizes both capacitance metrics.
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 method produces carbon particles with improved capacitive performance, increasing energy density and conductivity, while minimizing self-discharge, thus overcoming the limitations of existing carbon sphere technologies.
Implementation Method 1
The precursor solution is placed in a pressure vessel. The pressure vessel is heated to a reaction temperature to form carbon particles.
Implementation Method 2
The carbon particles are subjected to a chemical activation and a physical activation.
Implementation Method 3
The carbon particles are subjected to a chemical activation and a physical activation.
Data Source
AI summary
A composition generally includes carbon particles. The particles are prepared by dissolving a carbohydrate-based precursor in water to form a precursor solution and placing the precursor solution in a pressure vessel. The precursor solution is placed in a pressure vessel. The pressure vessel is heated to a reaction temperature to form carbon particles. The carbon particles are subjected to a chemical activation and a physical activation. The composition includes, by weight, about 5% to about 30% oxygen.