Pyrolytic Carbon-Coated Electrode Material for Battery Swelling Control
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Solution Overview
Problem
Lithium ion batteries face challenges with insufficient wettability of cathode materials, leading to barriers in lithium ion intercalation and deintercalation, which affects cycle characteristics and output, and are prone to cell swelling due to poor electron conductivity and stability issues.
Innovation Solution
An electrode material with a pyrolytic carbonaceous electron-conducting film coating on the surface of electrode active materials, where the surface acid amount is controlled between 1 μmol/m² and 5 μmol/m², is used, along with a manufacturing method involving the calcination of a mixture in a non-oxidative and acidic gas atmosphere to enhance conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pyrolytic carbonaceous electron-conducting film is coated on the surface of electrode active material particles, then electron conductivity is improved, but wettability with electrolytes becomes insufficient
Solution Approach 1:
The patent applies local quality by creating a carbonaceous film with specific local properties on the particle surface. The film is formed through pyrolysis of organic substances coated on electrode active material particles, creating a localized conductive layer that maintains electron conductivity while the controlled thickness and composition preserve adequate electrolyte wettability.
Solution Approach 2:
The patent utilizes parameter changes by controlling the pyrolysis conditions (temperature, atmosphere, duration) to adjust the properties of the carbonaceous film. By optimizing these parameters, the film achieves the right balance between electron conductivity and electrolyte wettability, preventing excessive carbon deposition that would harm wettability while ensuring sufficient conductivity.
2Reliability
If a large amount of conductive substance is used to improve electron conductivity, then conductivity increases, but electrode density decreases
Solution Approach 1:
The patent extracts only the necessary minimum amount of conductive substance by using in-situ pyrolysis of organic substances. This approach generates carbonaceous material directly at the particle surface where it is needed, avoiding the waste of conductive material that would occur with bulk mixing methods, thereby maintaining high electrode density while achieving sufficient conductivity.
Solution Approach 2:
The patent applies self-service by having the organic substance serve dual purposes: as a carbon source for conductivity enhancement and as a coating that adheres to the particle surface. The pyrolysis process transforms this organic material in-place into the conductive carbonaceous film, eliminating the need for separate conductive additive materials and their associated density penalties.
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 improves the cycle and input/output characteristics of lithium ion batteries, suppresses cell swelling, and maintains high discharge capacity while ensuring safety and reliability.
Implementation Method 1
a pyrolytic carbonaceous electron-conducting film that coats a surface of the electrode active material
Implementation Method 2
the calcination of a mixture in a non-oxidative and acidic gas atmosphere to enhance conductivity and stability
Data Source
AI summary
An electrode material having an electrode active material and a pyrolytic carbonaceous electron-conducting film that coats a surface of the electrode active material, in which an amount of a surface acid of the electrode material, which is determined by a back-titration method using tetrabutylammonium hydroxide, is 1 μmol/m2 or more and 5 μmol/m2 or less per surface area of the electrode material.