Coated Negative Electrode Material for Faster Solid-State Battery Charging
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Solution Overview
Problem
Solid-state batteries exhibit inferior charge rate characteristics compared to lithium-ion batteries using electrolyte solutions, primarily due to a reduced interface area between the negative electrode active material and the electrolyte, leading to slower charging times and reduced energy density.
Innovation Solution
A negative electrode material is developed comprising a negative electrode active material coated with a coating material represented by the formula LiaAbXc, where A is P or S, and X is F and O, which forms a favorable interface with a solid electrolyte, enhancing charge rate characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in the battery, then safety and stability are improved, but charge rate characteristics deteriorate
Solution Approach 1:
A coating layer comprising Li2SiO3 and Li3PO4 is formed on the surface of the negative electrode active material. This coating layer acts as an intermediary between the solid electrolyte and the negative electrode active material, facilitating lithium ion transfer while maintaining the safety and stability benefits of the solid electrolyte. The coating layer has high Li ion conductivity and forms a favorable interface, thereby improving charge rate characteristics without sacrificing the reliability advantages of solid electrolyte batteries.
2Quantity of substance
If the interface area between negative electrode active material and electrolyte is reduced, then energy density is improved, but charge rate characteristics worsen
Solution Approach 1:
A coating layer with specific local properties is applied to the surface of the negative electrode active material. This coating layer has high Li ion conductivity and forms a favorable interface with the solid electrolyte, creating a localized region of enhanced ion transfer capability. This allows the bulk of the electrode to maintain high energy density while the coated surface provides efficient charge transfer pathways, thus improving charge rate characteristics without significantly compromising energy density.
3Ease of manufacture
If conventional coating materials are used on negative electrode active material, then manufacturing simplicity is maintained, but charge rate characteristics and interface stability worsen
Solution Approach 1:
The coating layer composition is specifically designed to comprise Li2SiO3 and Li3PO4 in controlled proportions (Li2SiO3: 1-50 wt%, Li3PO4: 50-99 wt%). This parameter optimization creates a coating with high Li ion conductivity and favorable interface properties. The coating can be formed through conventional sintering processes at temperatures of 600-900°C, maintaining manufacturing simplicity while dramatically improving charge rate characteristics and interface stability compared to conventional coating materials.
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 coating material improves the charge rate characteristics of solid-state batteries by facilitating lithium ion transfer and reducing electrolyte deterioration, while maintaining sufficient Li ion conductivity and energy density.
Implementation Method 1
the coating material is represented by the following composition formula (1): LiaAbXc (1) where a, b, and c are each a positive real number, A is at least one selected from the group consisting of P and S, and X is F and O
Data Source
AI summary
A negative electrode material of the present disclosure includes a negative electrode active material, a solid electrolyte, and a coating material coating the negative electrode active material. The coating material is represented by the following composition formula (1), where a, b, and c are each a positive real number, A is at least one selected from the group consisting of P and S, and X is F and O.LiaAbXc (1)