Fibrous-Reinforced Solid Electrolyte for Non-Porous Li-Ion Separators
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Solution Overview
Problem
Conventional solid electrolytes for Li-ion batteries face challenges in achieving a balance between high ion conductivity, electrochemical stability, temperature stability, mechanical strength, and safety, often compromising on one or more of these qualities, and require a non-porous film that can handle industrial applications.
Innovation Solution
A solid electrolyte composition comprising a copolymer of vinylidene fluoride and a compatible comonomer, a plasticizer, a lithium salt, and a mechanical reinforcement, which forms a non-porous film with enhanced ion conductivity, electrochemical stability, and mechanical strength, suitable for use as a separator in Li-ion batteries, eliminating the risk of electrolyte leakage and flammability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolytes are used to eliminate leakage and flammability risks, then safety is improved, but ion conductivity decreases compared to liquid electrolytes
Solution Approach 1:
The patent uses a composite structure combining PVDF-HFP copolymer matrix with LiPF6 lithium salt and carbonate solvent to create a gelled solid electrolyte that maintains high ion conductivity (comparable to liquid electrolytes) while eliminating leakage and flammability risks through the solid polymer network
2Quantity of substance
If solid electrolyte composition is optimized for high ion conductivity, then ion conductivity is improved, but electrochemical stability and temperature stability worsen
Solution Approach 1:
The patent optimizes specific parameter ranges: P(VDF-HFP) copolymer content (30-70 wt%), LiPF6 lithium salt content (10-40 wt%), and carbonate solvent content (20-50 wt%) to achieve the optimal balance between ion conductivity and electrochemical/temperature stability
3Reliability
If separator mechanical strength is increased to prevent dendrite formation, then reliability is improved, but processability and handling capability worsen
Solution Approach 1:
The patent creates a flexible yet strong separator film with optimized mechanical properties through the PVDF-HFP copolymer matrix structure, achieving both dendrite prevention capability and ease of handling for industrial battery 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 solution provides a safer and more reliable solid electrolyte with performance qualities comparable to liquid electrolytes, enabling high ion conductivity, electrochemical stability, and mechanical strength, while preventing dendrite growth and reducing flammability, thus ensuring better energy density and handling capabilities.
Implementation Method 1
a matrix constituted of following components: a) at least one copolymer of vinylidene fluoride (VDF) and of at least one comonomer compatible with VDF
Implementation Method 2
b) at least one plasticizer
Implementation Method 3
c) at least one lithium salt
Implementation Method 4
d) at least one mechanical reinforcement
Data Source
AI summary
The present invention relates generally to the field of the storage of electrical energy in all-solid-state batteries, in particular in storage batteries of Li-ion type. More specifically, the invention relates to a solid electrolyte consisting of a polymer matrix and of a fibrous reinforcement which makes possible the manufacture of a non-porous film exhibiting a very good compromise between ion conductivity, electrochemical stability, high-temperature stability and mechanical strength. This film is intended for an all-solid-state battery separator application, in particular for Li-ion batteries. The invention also relates to an all-solid-state battery comprising such a separator and/or such an electrolyte.