Conductive Carbon for High Density Battery Electrodes
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Solution Overview
Problem
Existing electric storage devices face limitations in achieving high energy density due to difficulties in efficiently dispersing conductive carbon between active material particles, which restricts the increase in active material quantity per unit volume.
Innovation Solution
The use of conductive carbon with a hydrophilic solid phase component, characterized by specific crystallite sizes and a strong oxidizing treatment, enhances dispersibility and electrode density by allowing the carbon to spread and fill gaps between active material particles, thereby increasing the active material quantity per unit volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the quantity of conductive carbon per unit volume is increased to improve dispersibility, then the dispersibility of conductive carbon is improved, but the energy density of the electric storage device decreases
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of conductive carbon particles through oxidation treatment, introducing hydrophilic groups to enhance dispersibility in the electrolyte without increasing the volume fraction of conductive carbon. This allows improved dispersion while maintaining high energy density by keeping the active material content high.
Solution Approach 2:
The patent applies local quality by creating a hydrophilic surface layer on the conductive carbon particles through oxidation, while maintaining the core carbon structure. This localized modification improves dispersibility at the particle surface without affecting the overall composition ratio, enabling better distribution of conductive carbon at lower concentrations.
2Quantity of substance
If the distance between particles of active material is decreased to increase the quantity of active material per unit volume, then the energy density is improved, but the conductivity of the composite material deteriorates
Solution Approach 1:
The patent uses hydrophilic conductive carbon particles as intermediaries that bridge between active material particles. The oxidized surface of conductive carbon enhances wettability and creates better interfacial contact, facilitating electron transport between closely packed active material particles while maintaining adequate conductivity even at reduced conductive carbon content.
3Reliability
If conventional conductive carbon is used in composite material, then the conductivity is ensured, but the volume change of active material cannot be effectively absorbed
Solution Approach 1:
The patent employs composite material strategy by combining conductive carbon with oxidation treatment to create a material that possesses both electrical conductivity and enhanced interfacial adhesion. The oxidized surface creates stronger bonding with active material particles, enabling the conductive carbon network to effectively accommodate volume changes during electrochemical reactions while maintaining conductivity.
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 approach significantly increases electrode density and energy density of electric storage devices by improving the dispersibility and packing efficiency of active material particles, leading to enhanced performance.
Implementation Method 1
conductive carbon with a hydrophilic solid phase component, characterized by specific crystallite sizes and a strong oxidizing treatment, enhances dispersibility
Data Source
AI summary
Provided is conductive carbon which gives an electric storage device having a high energy density. This conductive carbon is characterized in having a hydrophilic solid phase component, where a crystallite size La that does not include a twist in a graphene surface direction and a crystallite size Leq that includes a twist in a graphene surface direction, which are calculated from a Raman spectrum of the hydrophilic solid phase component, satisfy the following relationships: 1.3 nm≦La≦1.5 nm, and 1.5 nm≦Leq≦2.3 nm, and 1.0≦Leq/La≦1.55. When performing a rolling treatment on an active layer including an active particle and this conductive carbon formed on a current collector during manufacture of an electrode of an electric storage device, the pressure resulting from the rolling treatment causes this conductive carbon to spread in a paste-like form and increase in density while covering the surface of the active particles, the conductive carbon being pressed into gaps formed between adjacent active particles and filling the gaps. As a result, the amount of active material per unit volume in the electrode obtained after the rolling treatment increases, and the electrode density increases.