Solid-State Battery Anode Coating for Low Interfacial Resistance
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Solution Overview
Problem
All-solid secondary batteries face challenges with high interfacial resistance between the anode and solid electrolyte, which affects battery capacity and stability, particularly due to the spring back phenomenon during high-temperature and high-pressure activation of sulfide-based solid electrolytes.
Innovation Solution
Incorporating natural graphite with an average particle diameter between 10 μm to 20 μm and an amorphous carbon coating layer as the anode material, which reduces interfacial resistance and enhances lithium ion mobility, thereby improving battery capacity and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-temperature and high-pressure conditions are applied to activate sulfide-based solid electrolyte, then ionic conductivity is improved, but interfacial resistance increases due to spring back phenomenon
Solution Approach 1:
The patent applies pressure to the battery stack during assembly to maintain contact between the solid electrolyte and electrodes, compensating for the spring back phenomenon that occurs after high-temperature activation. This parameter change (applying mechanical pressure) resolves the contradiction by preventing interfacial separation while allowing the solid electrolyte to achieve its activated state with high ionic conductivity.
2Reliability
If pressure is applied to reduce interfacial resistance, then contact between electrode and solid electrolyte is improved, but battery structure stability may be compromised
Solution Approach 1:
The patent applies pressure during the battery assembly process before final sealing, establishing optimal contact between components in advance. This preliminary action ensures low interfacial resistance is achieved during the critical formation phase, while the sealed structure maintains stability during operation without requiring continuous external pressure.
3Speed
If natural graphite with larger particle diameter is used as anode material, then lithium ion mobility is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a particular particle diameter range (10-20 μm) for natural graphite that optimizes the balance between lithium ion mobility and manufacturing feasibility. This parameter selection resolves the contradiction by identifying a sweet spot where larger particles provide adequate ion transport pathways while remaining controllable through standard manufacturing processes.
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 use of natural graphite with an amorphous carbon coating layer in the anode material significantly reduces interfacial resistance and enhances battery capacity and lifespan by stabilizing lithium ion migration, even when a sulfide-based solid electrolyte is used.
Implementation Method 1
the natural graphite has an average particle diameter (D50) in a range of greater than about 10 μm to about 20 μm or less, and includes an amorphous carbon coating layer
Data Source
AI summary
An all-solid secondary battery includes a cathode; an anode including natural graphite; and a solid electrolyte layer between the cathode and the anode, wherein the natural graphite has an average particle diameter (D50) in a range of greater than about 10 μm to about 20 μm or less and includes an amorphous carbon coating layer.