PVA-Polyester Solid Electrolyte for High Ionic Conductivity
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Solution Overview
Problem
Current polymer electrolytes for solid-state lithium/sodium batteries, particularly those based on polyvinyl alcohol (PVA), face challenges with low ionic conductivity and poor electrochemical stability in dry conditions, limiting their performance and environmental friendliness.
Innovation Solution
Development of a novel PVA-based dry polymer electrolyte with high ionic conductivity and improved lithium transference number, achieved through partial or total esterification of PVA with specific compounds and subsequent formation of carbamate ester groups, followed by treatment with lithium or sodium carbonates to create a solid electrolyte with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PVA-based dry polymer electrolytes are used, then environmental friendliness and biodegradability are improved, but ionic conductivity deteriorates
Solution Approach 1:
The patent creates a composite polymer electrolyte by combining PVA with polyester chains containing carbonyl groups and lithium/sodium salts. This composite structure maintains the environmental benefits of PVA while the polyester segments and metal salts provide the necessary ionic conductivity pathways, resolving the contradiction between eco-friendliness and conductive performance
Solution Approach 2:
The patent modifies the chemical parameters of PVA through esterification reactions, introducing carbonyl-containing polyester segments and metal salt complexes. These parameter changes transform the bulk properties of the polymer, enabling dry-state ionic conductivity to reach 10^-4 S/cm while preserving the biodegradable nature of the PVA backbone
2Reliability
If plasticizers or liquid electrolytes are added to improve ionic conductivity, then ionic conductivity is improved, but device complexity and processing difficulty increase
Solution Approach 1:
The patent extracts and eliminates the liquid electrolyte component from the system, developing a fully solid-state polymer electrolyte. By incorporating ionic conductivity-enhancing segments directly into the polymer matrix through esterification and salt complexation, the invention achieves high conductivity without requiring separate liquid electrolyte phases, plasticizers, or complex multilayer structures
Solution Approach 2:
The patent merges the functions of the polymer matrix, ionic conductor, and electrolyte into a single integrated solid polymer material. The PVA-polyester-salt composite simultaneously provides structural integrity, ionic transport pathways, and electrochemical stability, simplifying device architecture and manufacturing processes compared to gel or liquid electrolyte systems
3Reliability
If PEO-based polymer electrolytes are used, then ionic conductivity is improved, but electrochemical stability and mechanical stability deteriorate
Solution Approach 1:
The patent introduces localized carbonyl-containing polyester segments and metal salt complexes within the PVA matrix at specific compositions (5-50 mol%). These localized regions provide high ionic conductivity pathways while the bulk PVA structure maintains electrochemical stability and mechanical integrity, creating a heterogeneous structure with optimized local properties
Solution Approach 2:
The invention creates a composite structure combining PVA chains with polyester segments containing carbonyl groups and lithium/sodium salts. This composite architecture leverages the electrochemical stability of PVA, the coordination capability of carbonyl groups for ion transport, and the ionic conductivity of metal salts, achieving both stability and conductivity simultaneously
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 new electrolyte exhibits high ionic conductivity and good electrochemical stability, suitable for energy storage devices, including batteries, with improved lithium or sodium ion transport and stability, addressing the limitations of existing PVA-based electrolytes.
Implementation Method 1
Under the effect of an electric field, the salt cations tend to hop from one coordinating site (usually composed of more than three electron donor groups) to another
Implementation Method 2
coordinating site (usually composed of more than three electron donor groups)
Implementation Method 3
partial or total esterification of the hydroxyl groups of a polymer comprising at least 50 mol% of recurring units of formula (IV)
Implementation Method 4
formation of carbamate ester groups by reaction of hydroxyl groups of the partially esterified polymer obtained in step a) with an isocyanate of formula (VI)
Implementation Method 5
formation of the lithium or sodium salt of the carbamate ester groups of the polymer obtained in step b1) by treatment of said polymer with Li2CO3 for formation of the lithium salt, or Na2CO3 or NaHCO3 for formation of the sodium salt
Data Source
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AI summary
The present invention relates to a solid electrolyte comprising a polymer and a salt selected from the group consisting of a lithium salt, a sodium salt and mixtures thereof, wherein the polymer comprises at least 50 mol% of recurring units of formula (I), to a method for the preparation of said electrolyte, its uses and energy storage devices comprising said electrolyte.