Polyacrylamide Polymer Electrolyte for High-Voltage NMC Cathodes
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Solution Overview
Problem
Conventional lithium secondary batteries with liquid electrolytes pose safety risks due to flammability and leakage, while solid electrolytes face challenges in achieving high ionic conductivity, broad electrochemical window, and compatibility with high-potential cathode materials like NMC622 or NMC811, and require a stable polymer backbone for encapsulating liquid electrolytes.
Innovation Solution
A polymer electrolyte comprising a polymeric network based on specific (meth)acrylamide monomers effectively encapsulates deep eutectic solvents and is compatible with high-potential cathode active materials, such as NMC622, by polymerizing a precursor composition containing a first monomer and a crosslinker, forming a three-dimensional polymer network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in lithium secondary batteries, then high ionic conductivity is achieved, but safety risks increase due to flammability and leakage
Solution Approach 1:
The liquid electrolyte is nested within the three-dimensional polymer network structure, creating a composite electrolyte system where the liquid electrolyte is confined and stabilized by the solid polymer matrix, eliminating leakage risks while maintaining ionic conductivity
Solution Approach 2:
A composite electrolyte is formed by combining the liquid electrolyte with the polymer network comprising (meth)acrylamide monomers and crosslinkers, creating a gel-like structure that integrates the advantages of both liquid and solid electrolytes
2Object-affected harmful factors
If conventional solid electrolytes are used, then safety is improved by reducing flammability, but ionic conductivity and compatibility with high-potential cathode materials deteriorate
Solution Approach 1:
The composite electrolyte combines the safety advantages of solid electrolytes with the high ionic conductivity of liquid electrolytes, creating a material that exhibits both low flammability and high ion transport capability
Solution Approach 2:
The polymer network parameters (monomer selection, crosslinking density, network architecture) are optimized to achieve the right balance between mechanical stability and ionic conductivity, allowing the electrolyte to function effectively at high voltages
3Stability of the object's composition
If conventional solid polymer electrolytes are used, then mechanical stability is achieved, but compatibility with high-potential cathode materials like NMC622 deteriorates due to limited anodic stability
Solution Approach 1:
The chemical composition parameters of the polymer network are changed by selecting specific (meth)acrylamide monomers and crosslinkers that provide both mechanical stability and chemical inertness against high-potential cathode materials, enabling operation at voltages above 4.0V vs Li+/Li
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 polymer electrolyte exhibits excellent cycling stability and anodic stability, enabling compatibility with high-voltage cathode materials, and can be pre-synthesized with or without the cathode, providing a safe and efficient electrochemical cell.
Implementation Method 1
a polymer electrolyte which is obtainable by polymerizing a precursor composition which comprises the electrolyte composition and a first monomer
Implementation Method 2
deep eutectic solvents, and a polymer network having a polyacrylamide backbone
Data Source
AI summary
The present invention relates to an electrochemical cell comprising an anode, a polymer electrolyte and an NMC type cathode active material. The polymer electrolyte comprises an electrolyte composition, preferably comprising a deep eutectic solvent (DES), and a polymer network having a polyacrylamide backbone.