All-Solid-State Battery Outer Layer for Low-Temperature Co-Firing
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Solution Overview
Problem
All-solid-state batteries face challenges with low lithium ionic conductivity and deteriorated adhesive strength due to voids and grains generated in electrode layers during the co-firing process at low temperatures.
Innovation Solution
The battery design includes a solid electrolyte layer between positive and negative electrode layers, with an oxide of a sintering aid added to the electrode layers to form a composite with the solid electrolyte, reducing interfacial resistance and enhancing adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If co-firing is performed at low temperature to simplify manufacturing, then energy consumption is reduced, but voids and grains are generated in electrode layers causing high resistance and low lithium ionic conductivity
Solution Approach 1:
A buffer layer is introduced between the electrode layer and solid electrolyte layer to act as an intermediary. This buffer layer prevents direct contact that would cause void formation, while still allowing lithium ion transport. The buffer layer comprises a material different from both the electrode active material and solid electrolyte, serving as a mediating substance that resolves the contradiction between low-temperature processing and maintaining ionic conductivity.
Solution Approach 2:
The electrode layer is designed as a composite structure containing electrode active material particles, solid electrolyte particles, and buffer layer particles. This composite material approach allows the system to benefit from the low-temperature processing capability of the solid electrolyte while the buffer layer compensates for the void formation issue, maintaining lithium ionic conductivity through the composite structure.
2Manufacturing precision
If co-firing is performed at low temperature to simplify manufacturing, then manufacturing precision is maintained, but adhesive strength between electrode layer and solid electrolyte deteriorates
Solution Approach 1:
The buffer layer serves as a bonding intermediary between the electrode layer and solid electrolyte layer. It provides a large contact area with both adjacent layers, enabling effective stress distribution and strong adhesion. The buffer layer material is specifically selected to form strong interfaces with both the electrode active material and solid electrolyte, resolving the adhesive strength issue while maintaining low-temperature manufacturing precision.
3Reliability
If solid electrolyte is impregnated in each electrode layer to improve ionic conductivity, then lithium ionic conductivity increases, but resistance between electrode active material and solid electrolyte increases due to voids and grains
Solution Approach 1:
The buffer layer acts as a mediator that eliminates voids at the interface between electrode active material and solid electrolyte. By placing buffer layer particles in the spaces between electrode active material particles and forming a continuous network, it ensures complete solid electrolyte impregnation without void formation, thereby maintaining high lithium ionic conductivity and excellent interface quality simultaneously.
4Adaptability or versatility
If different surface properties between electrode active material and solid electrolyte are present, then material compatibility is achieved, but adhesive strength deteriorates
Solution Approach 1:
The buffer layer serves as a surface property intermediary that bridges the mismatch between electrode active material and solid electrolyte surfaces. It provides compatible surface characteristics for both materials, enabling strong adhesion through multiple contact interfaces while maintaining the distinct properties of the electrode active material and solid electrolyte for their respective functions.
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 approach enables high ionic conductivity and high power performance by reducing resistance and improving adhesive strength between electrode active materials and the solid electrolyte, even when co-firing at low temperatures.
Implementation Method 1
the solid electrolyte is an amorphous solid electrolyte including a Li (lithium) oxide, a Si (silicon) oxide, a B (boron) oxide, or a combination thereof
Implementation Method 2
a positive electrode layer and a negative electrode layer with the solid electrolyte layer disposed therebetween; wherein the positive electrode layer includes a positive electrode active material and a solid electrolyte, the negative electrode layer includes a negative electrode active material and a solid electrolyte, the positive electrode layer or the negative electrode layer includes an oxide of a sintering aid
Data Source
AI summary
An all-solid-state battery according to present disclosure includes a cell stack including a solid electrolyte layer, and a positive electrode layer and a negative electrode layer with the solid electrolyte layer disposed therebetween, and an outermost layer on one surface or both surfaces of the cell stack in a stacking direction, wherein the outermost layer includes an epoxy resin and glass particles and the glass particles include a boron (B) oxide, a silicon (Si) oxide, and an aluminum (Al) oxide.