Activated Carbon Electrode Production via Oxidation and Particle Size Control
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Solution Overview
Problem
The existing methods for producing activated carbon for electric double layer capacitors require a large amount of alkali activator, leading to high production costs and inefficient activation due to poor wettability between the carbon material and the activator.
Innovation Solution
Adjusting the carbon material to a particle diameter of 0.5 to 15 μm and oxidizing it to contain 3% or more oxygen, allowing for improved wettability with an alkali activator, thus reducing the amount of activator needed and enhancing the activation reaction's uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large amount of alkali activator is used to increase the specific surface area of activated carbon, then the surface area increases, but the production cost increases due to the high ratio of activator to carbon material
Solution Approach 1:
The invention changes the particle size parameter of carbon material to 0.5 to 15 μm (preferably 1 to 12 μm) and oxidizes it to contain 3% or more oxygen, which fundamentally alters the physical and chemical properties of the carbon material. This enables the activator to penetrate and react more efficiently, achieving high surface area (2000-3000 m²/g) with lower activator ratios (1.5:1 to 3:1 mass ratio of activator to carbon material).
Solution Approach 2:
The carbon material is pre-oxidized before activation to introduce oxygen-containing functional groups on the surface. This preliminary oxidation treatment creates favorable conditions for subsequent activator penetration and reaction, improving contact efficiency and reducing the amount of activator needed while maintaining high surface area development.
2Ease of manufacture
If simple mixture of carbon material and alkali activator is used, then the process is simple, but the contact between activator and carbon material is insufficient leading to large amount of activator being wasted
Solution Approach 1:
By changing the particle size to 0.5-15 μm and introducing oxygen through oxidation, the carbon material's surface properties are fundamentally altered. This creates better interfacial contact between the hydrophilic oxidized surface and the aqueous alkali activator, dramatically improving penetration efficiency and reducing activator waste while maintaining process simplicity.
Solution Approach 2:
Oxygen-containing functional groups act as an intermediary that facilitates contact between the carbon material and the alkali activator. These groups improve wettability and create favorable chemical environments for activator penetration, enabling efficient reaction with less activator while keeping the mixing process simple.
3Loss of substance
If mechanical mixing with ball mill or Henschel mixer is used to improve contact, then the contact efficiency improves, but the process complexity and cost increase
Solution Approach 1:
The invention achieves superior contact efficiency through parameter changes in the carbon material itself (particle size 0.5-15 μm and oxygen content ≥3%) rather than through complex mixing equipment. The oxidized surface creates inherent affinity for the activator, enabling simple mixing to achieve what would otherwise require sophisticated mechanical mixing systems.
Solution Approach 2:
The oxidized carbon material essentially prepares itself for activation by developing surface properties that naturally attract and retain the alkali activator. This self-preparation eliminates the need for complex external mixing equipment, as the material's own modified properties ensure efficient contact during simple mixing operations.
4Area of stationary object
If the carbon material particle size is not controlled, then the material is easier to handle, but the activation reaction uniformity decreases leading to smaller surface area
Solution Approach 1:
The invention establishes a specific particle size range (0.5 to 15 μm, preferably 1 to 12 μm) that optimizes both handling and activation uniformity. This controlled size range ensures sufficient surface area for reaction while maintaining manageable physical properties. The oxidation treatment further enhances uniformity by creating consistent surface chemistry across all particles in this size range.
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
This method results in a significant reduction in production costs and the production of activated carbon with a large surface area, achieving high capacitance per unit volume in electric double layer capacitors.
Implementation Method 1
oxidizing it to contain 3% or more oxygen
Implementation Method 2
improved wettability with an alkali activator
Implementation Method 3
activating the oxidized product with an alkali activator
Implementation Method 4
forms fine pores
Data Source
AI summary
The present invention provides a method for producing an activated carbon for an electric double layer capacitor, with which the wettability of a carbon material with an alkali activator is improved, thereby improving contact efficiency between the carbon material and the alkali activator and efficiently promoting reaction between the carbon material, which is a starting material and the activator. The method comprises adjusting a carbon material as it is or after having been calcined to produce a carbon powder having an average particle diameter of 0.5 to 15 μm, oxidizing the carbon powder to contain 3 percent by mass or more of oxygen, and activating the oxidized product with an alkali activator.