Solid-State Li-Ion Anode Layering to Suppress Dendrites
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Solution Overview
Problem
Existing all-solid-state lithium-ion secondary batteries require high external pressure to prevent the formation of dendrites and voids due to metal lithium precipitation, which hinders thinning and reduces discharge capacity and lifetime.
Innovation Solution
The battery design includes a negative electrode active material layer composed of carbon material and Ag, structured with two or more sub-layers, where the sub-layer adjacent to the negative electrode current collector has a higher Ag content than the sub-layer adjacent to the solid electrolyte, eliminating the need for high external pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high external pressure is applied using end plates to prevent void formation, then reliability is improved, but device complexity increases and thinning is hindered
Solution Approach 1:
The patent removes the end plates that apply external pressure from the battery structure. Instead of using mechanical pressure application, the invention uses an amorphous carbon interface layer that inherently prevents void formation through its material properties, thereby eliminating the need for complex pressure application mechanisms while maintaining battery reliability
Solution Approach 2:
The patent introduces an amorphous carbon interface layer as an intermediary between the metal layer and the electrolyte. This intermediate layer prevents direct contact and reaction between metal lithium and the electrolyte, thereby preventing void formation without requiring external pressure. The amorphous carbon layer acts as a mediator that solves the reliability issue through its unique material properties rather than mechanical force
2Reliability
If amorphous carbon interface layer is used to prevent void formation, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the material parameter of the interface layer from crystalline or other structured carbon to amorphous carbon. This parameter change in the material structure provides inherent void prevention capabilities without requiring precise control of layer thickness or uniformity, thereby reducing manufacturing precision requirements while improving reliability
3Quantity of substance
If metal lithium is used as negative electrode active material, then energy density is improved, but dendrite formation increases
Solution Approach 1:
The patent uses an amorphous carbon interface layer as an intermediary between metal lithium and the electrolyte. This intermediate layer prevents direct interaction that would lead to dendrite formation, while still allowing lithium ion transport. The amorphous carbon structure provides a protective interface that enables the use of high-capacity metal lithium without the harmful dendrite effect
Solution Approach 2:
The patent creates a composite structure consisting of metal lithium, amorphous carbon, and electrolyte. The amorphous carbon component in this composite material system provides dendrite suppression capabilities while maintaining the high energy density benefits of metal lithium, effectively combining the advantages of different 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
This design suppresses dendrite formation and enhances discharge capacity and lifetime characteristics without requiring external pressure, improving the battery's overall performance.
Implementation Method 1
a solid electrolyte interposed between the positive electrode and the negative electrode
Implementation Method 2
the negative electrode active material layer comprises a carbon material and Ag
Data Source
AI summary
An all-solid-state lithium-ion secondary battery includes a positive electrode, a negative electrode, and a solid electrolyte between the positive electrode and the negative electrode. The negative electrode has a negative electrode current collector and a negative electrode active material layer that comprises a carbon material and Ag.