Solid-State Battery Carbon Interlayers Against Lithium Dendrites
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Solution Overview
Problem
All-solid-state batteries face issues with lithium dendrite formation and mechanical instability due to repeated charging and discharging, leading to potential short circuits and electrolyte damage.
Innovation Solution
Incorporating composite carbon layers with different binder content ratios between the solid electrolyte membrane and negative electrode to enhance electrical conductivity and mechanical stability, with the first layer having a higher binder content for elasticity and the second layer having a lower binder content to induce lithium diffusion in the plane direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte membrane is used in an all-solid-state battery, then safety and reliability are improved by preventing electrolyte leakage, but lithium dendrite generation occurs during repeated charging and discharging leading to short circuits
Solution Approach 1:
A composite carbon layer is introduced as an intermediary between the solid electrolyte membrane and the lithium metal negative electrode. This intermediate layer prevents direct contact between lithium dendrites and the solid electrolyte membrane, blocking the harmful effect while maintaining the safety benefits of the solid electrolyte system.
Solution Approach 2:
The patent uses a composite carbon layer composed of carbon particles and binder material. This composite structure provides both electrical conductivity (from carbon particles) and mechanical flexibility (from binder), creating a material that can accommodate lithium dendrite growth while maintaining structural integrity and preventing short circuits.
2Duration of action of stationary object
If composite carbon layers with different binder content are used between solid electrolyte membrane and negative electrode, then lifetime characteristics and interfacial stability are improved, but device complexity increases due to multiple layers with different compositions
Solution Approach 1:
The patent applies the local quality principle by creating two distinct composite carbon layers with different binder contents positioned at different locations. The first layer (adjacent to solid electrolyte membrane) has higher binder content (5-20 wt%) for mechanical stability and interface adhesion, while the second layer (adjacent to negative electrode) has lower binder content (1-5 wt%) for electrical conductivity and lithium ion transport. Each layer's composition is optimized for its specific functional requirements.
3Object-affected harmful factors
If the separator in a lithium-ion battery is damaged due to deformation or external impact, then a short circuit occurs leading to overheating or explosion, but using a solid electrolyte membrane prevents such damage, however lithium dendrite can still cause short circuits
Solution Approach 1:
The composite carbon layer acts as a preemptive protective barrier that cushions and absorbs the mechanical stress and deformation caused by lithium dendrite growth before it can reach and damage the solid electrolyte membrane. This prior cushioning prevents the harmful effect of short circuits while maintaining the inherent safety advantages of solid electrolyte batteries.
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 composite carbon layers improve the physical and mechanical stability of the battery, preventing lithium dendrite precipitation and enhancing the lifetime characteristics by maintaining interfacial stability and protecting the solid electrolyte membrane from volume changes.
Implementation Method 1
the content of the binder in the first composite carbon layer is 10 to 20 wt% based on the total weight of the carbon material and the binder, the content of the binder in the second composite carbon layer is 1 to 5 wt% based on the total weight of the carbon material and the binder
Implementation Method 2
precipitate lithium in the plane direction between the composite carbon layers
Data Source
Figure 1~2
AI summary
The present invention relates to an all-solid-state battery comprising a positive electrode, a negative electrode and a solid electrolyte membrane interposed between the positive electrode and the negative electrode, and further comprising a first composite carbon layer and a second composite carbon layer between the negative electrode and the solid electrolyte membrane.