Carbon-Coated Battery Active Material via Liquid CO2 Coating
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Solution Overview
Problem
Current methods for coating secondary battery active materials with carbon result in low uniformity, leading to reduced energy density and increased environmental pollution, as they require excessive carbon and generate waste solutions, failing to enhance electrical conductivity and safety effectively.
Innovation Solution
A method involving the use of liquid carbon dioxide to dissolve carbon precursors, allowing for uniform coating of secondary battery active materials, followed by sintering to form a carbon layer, which improves electrical conductivity and energy density while minimizing carbon usage and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional carbon coating methods are used, then carbon coating is applied to secondary battery active materials, but the coating uniformity is low and excessive carbon is required
Solution Approach 1:
The patent changes the physical state parameter of carbon dioxide from gas to liquid/supercritical phase to achieve uniform coating. By controlling temperature and pressure parameters, carbon dioxide dissolves carbon precursors uniformly and then deposits as a thin, even layer on the active material surface, eliminating the need for excessive carbon while achieving high coating uniformity.
Solution Approach 2:
The patent utilizes phase transitions of carbon dioxide (gas→liquid/supercritical→gas) to achieve coating. Carbon dioxide is converted to liquid or supercritical state for dissolution and coating application, then returns to gas state for easy removal, leaving uniform carbon deposits. This phase transition mechanism enables precise control of carbon deposition amount and uniformity.
2Reliability
If conventional carbon coating methods are used, then carbon coating is applied to enhance electrical conductivity, but waste solutions are generated causing environmental pollution
Solution Approach 1:
The patent uses carbon dioxide as an inert solvent medium that does not generate harmful waste products. Carbon dioxide is environmentally benign, non-flammable, and can be easily separated from the coating process by pressure release. This eliminates the need for organic solvents that create toxic waste, thereby maintaining electrical conductivity enhancement while avoiding environmental pollution.
Solution Approach 2:
The patent enables easy recovery and recycling of carbon dioxide solvent through pressure control. After coating, carbon dioxide is simply released from its liquid/supercritical state back to gas, allowing for complete solvent recovery without waste treatment. This closed-loop approach eliminates environmental pollution while maintaining the electrical conductivity benefits of carbon coating.
3Manufacturing precision
If conventional carbon coating methods are used, then coating is applied to active materials, but the coating thickness is not nano-scale uniform
Solution Approach 1:
The patent replaces complex mechanical coating systems with a chemical dissolution-deposition process. Instead of using mechanical application methods that struggle to achieve uniform nano-scale thickness, the invention uses carbon dioxide to dissolve carbon precursors and deposit them uniformly through controlled phase transitions. This chemical approach naturally produces nano-scale uniform thickness without complex mechanical control systems.
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 achieves a uniform carbon coating with a nano-scale thickness, enhancing the electrical conductivity and energy density of secondary battery active materials, while reducing carbon content and simplifying waste treatment processes, thus improving battery performance and safety.
Implementation Method 1
forming a coating solution comprising a carbon precursor dissolved in liquid carbon dioxide
Implementation Method 2
coating a surface of a secondary battery active material with the carbon precursor by immersing the secondary battery active material in the coating solution
Implementation Method 3
sintering the secondary battery active material coated with the carbon precursor
Implementation Method 4
sintering the secondary battery active material coated with the carbon precursor
Implementation Method 5
removing the liquid carbon dioxide after coating the secondary battery active material with the carbon precursor and before sintering
Data Source
AI summary
Disclosed is a method of carbon-coating a secondary battery active material and a second battery active material produced by the method. The method of producing a carbon-coated battery active material involves mixing a carbon precursor with liquid carbon dioxide to produce a coating solution comprising a carbon material, coating a battery active material with the carbon material by applying the coating solution to the battery active material, and sintering the coated battery active material to obtain the carbon-coated battery active material.