Composite Solid Electrolyte Membrane for Lithium-Ion Battery Safety
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Solution Overview
Problem
Conventional lithium-ion batteries face safety issues due to the volatility of liquid electrolytes and the fragility and low mechanical strength of solid electrolyte membranes, limiting their application in high-energy density batteries.
Innovation Solution
A composite solid electrolyte membrane is developed with alternately laminated inorganic solid electrolyte layers and structure supporting layers, ensuring well-contacted inorganic solid electrolyte particles and enhanced mechanical processing properties, allowing for high lithium ionic conductivity and improved safety and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolyte is used, then lithium ionic conductivity is improved, but safety performance deteriorates due to volatility and flammability
Solution Approach 1:
The patent uses a composite solid electrolyte membrane comprising inorganic solid electrolyte particles dispersed in a polymer matrix. This composite structure combines the high lithium ionic conductivity of inorganic materials with the mechanical flexibility and safety of polymer materials, eliminating the flammability issue of liquid electrolytes while maintaining good ionic conductivity.
2Object-affected harmful factors
If polymer solid electrolyte is used, then safety performance is improved, but lithium ionic conductivity deteriorates at room temperature
Solution Approach 1:
The patent creates a composite solid electrolyte membrane with inorganic solid electrolyte particles (such as LLZO, LATP, or LTO) dispersed in a polymer matrix. The inorganic particles provide high lithium ionic conductivity pathways, while the polymer matrix provides mechanical flexibility and safety, achieving both high conductivity and safety performance simultaneously.
Solution Approach 2:
The patent optimizes the local distribution and concentration of inorganic solid electrolyte particles within the polymer matrix to create conductive pathways. By controlling the particle size, shape, and spatial distribution, the patent ensures sufficient ionic conductivity while maintaining the mechanical integrity and safety of the polymer matrix.
3Reliability
If inorganic solid electrolyte membrane is made thinner, then lithium ionic conductivity is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent uses a composite structure where inorganic solid electrolyte particles are embedded in a polymer matrix. This allows the membrane to be made thin for high ionic conductivity while the polymer matrix provides the necessary mechanical strength and flexibility to prevent fracture, solving the thickness-strength trade-off.
Solution Approach 2:
The patent employs a flexible polymer matrix that can form thin films while maintaining mechanical integrity. The polymer shell surrounding the inorganic particles provides flexibility and prevents brittleness, enabling the membrane to be made thin without sacrificing mechanical strength.
Data Source
AI summary
The present disclosure provides a cell and a preparation method thereof. The cell comprises a positive electrode plate (1); a negative electrode plate (2) and a composite solid electrolyte membrane (3) positioned between the positive electrode plate (1) and the negative electrode plate (2). The composite solid electrolyte membrane (3) comprises inorganic solid electrolyte layers (31) and structure supporting layers (32) which are alternately laminated along a laminating direction (D), and has abutted surfaces (S1) respectively abutting against the positive electrode plate (1) and the negative electrode plate (2), an angle between the laminating direction (D) and the abutted surface (S1) is defined as α, and 0°≦α<90°. The composite solid electrolyte membrane not only plays an advantage of a high lithium ionic conductivity of the inorganic solid electrolyte, but also has an excellent mechanical processing property, thereby significantly improving electrochemical performance and safety performance of the cell.