Carbon Precursor Material for Thin Homogeneous Electrode Coatings
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Solution Overview
Problem
Conventional carbon coatings for battery electrodes are not always homogeneously distributed, leading to thick films that increase charge losses and reduce cycling stability, while also containing metal impurities that pose safety risks and limit the availability of high-quality coal tar pitch due to environmental concerns.
Innovation Solution
A carbon precursor material derived from the distillation residue of coal tar and/or petroleum-based raw materials, which has a softening point between 7° and 120° C. and a low toluene insoluble content, is used to create a thin, homogeneous carbon coating for battery electrodes, enhancing their quality and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon coating is applied to electrode material particles, then the particle surface is covered to reduce reactivity and improve safety, but the coating is not homogeneously distributed resulting in thick films that increase charge losses
Solution Approach 1:
The invention changes the physical and chemical parameters of the coating material by using a specific distillate fraction with controlled softening point (7-120°C Mettler) and toluene insoluble content (<12%). These parameter changes enable the coating material to achieve homogeneous distribution at lower thickness while maintaining protective functions, thereby reducing charge losses without compromising safety.
Solution Approach 2:
The invention applies coating material with locally optimized properties - the distillate fraction is specifically selected to have appropriate softening point and insoluble content that match the requirements for homogeneous surface coverage. This local quality optimization ensures that the coating forms a uniform thin layer rather than thick non-uniform films, reducing energy losses while maintaining protective functionality.
2Ease of manufacture
If conventional pitches are used for carbon coating, then coating can be formed, but metal impurities and particle contaminants are present that reduce coating quality and pose safety risks
Solution Approach 1:
The invention extracts and removes harmful impurities from the coating material by using a specific distillate fraction obtained through controlled distillation. The process separates and eliminates metal particles and contaminants that would otherwise be present in conventional pitches, resulting in a purified coating material that forms high-quality carbon layers without safety risks associated with impurities.
Solution Approach 2:
The invention changes the purity parameters of the coating material by specifying toluene insoluble content of less than 12% and controlling the distillation range. This parameter control ensures that harmful metal impurities and particle contaminants are excluded from the final coating material, while maintaining the ease of manufacture through controlled distillation processes.
3Reliability
If thicker carbon coatings are applied to ensure complete surface coverage, then reactivity towards electrolyte is reduced, but the insertion rate of lithium ions into the bulk is influenced negatively
Solution Approach 1:
The invention changes the quality parameters of the carbon coating by using a distillate fraction with optimized softening point and low insoluble content. This produces a homogeneous thin coating that provides sufficient surface coverage to reduce reactivity while maintaining porosity and structure that allows fast lithium ion insertion, thus improving speed without sacrificing reliability.
Solution Approach 2:
The invention applies just enough coating material to achieve homogeneous surface coverage and adequate protection, avoiding excessive thickness. The optimized coating material provides maximum effectiveness at minimum thickness, ensuring sufficient reactivity reduction while preserving lithium ion insertion rate through appropriate coating density and uniformity rather than sheer thickness.
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 carbon precursor material results in a thin, homogeneous carbon coating that improves the electrochemical performance of battery electrodes by reducing charge losses and increasing cycling stability, while also minimizing safety risks and ensuring a secure supply of materials.
Implementation Method 1
A carbon precursor material is provided comprising a distillation residue from a distillate, said distillate being a distillate fraction of coal tar and/or petroleum-based raw material
Implementation Method 2
thin homogeneous coatings are expected when using coating materials showing good wetting and impregnation of the particle surface
Implementation Method 3
The mixture then is heated in an inert gas atmosphere to melt the pitch and form the superficial layer that is finally carbonized at elevated temperatures
Data Source
AI summary
A carbon precursor material is provided that includes a distillation residue from a distillate fraction of coal tar and/or petroleum-based raw material, or of coal tar-based and/or petroleum-based pitch. The distillation residue has a softening point between 7° and 120° C. Mettler. The carbon precursor material functions as a binder and/or impregnation material in the manufacturing of graphite electrodes for electric arc furnaces and carbon anodes for aluminum production, or as coating material for carbon-coated particles for the manufacturing of battery electrodes. A process for obtaining a carbon precursor material includes providing coal tar and/or petroleum-based raw material, or a coal tar-based and/or petroleum-based pitch, exposing the raw material or the pitch to a first vacuum distillation process, thereby obtaining a raw distillate fraction, subsequently exposing the raw distillate fraction to a second vacuum distillation process, thereby obtaining a distillation residue being the carbon precursor material.