Composite Cathode Electrolyte for Lithium Battery Conductivity
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Solution Overview
Problem
Current lithium ion batteries face challenges with contamination from organic solvents, mechanical integrity issues due to waxy plastic crystal matrices, and limited room temperature ionic conductivity, which affect stability and shelf life, particularly in electric vehicles where space and safety are concerns.
Innovation Solution
A composite cathode is created using a precursor polymer electrolytic solution with a plasticizer, crosslinkable polyether, and dual lithium salts, which is impregnated into cathodic materials like Lithium Iron Phosphate, enhancing electrochemical stability and ionic conductivity without the need for organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic solvents are used to ionize lithium salt and promote ion transport, then ionic conductivity is improved, but contamination occurs reducing battery shelf life
Solution Approach 1:
The patent removes organic solvents from the electrolyte composition entirely, extracting the harmful component while retaining the essential function of ion transport through a solvent-free polymer gel electrolyte system
Solution Approach 2:
The patent changes the physical and chemical parameters of the electrolyte by transitioning from a liquid organic solvent system to a solid polymer gel system, fundamentally altering the state of matter and eliminating solvent-related contamination
2Reliability
If plastic crystal matrix is used to achieve high ionic conductivity, then ionic conductivity is improved, but mechanical integrity is lost due to waxy substance
Solution Approach 1:
The patent creates a composite polymer gel electrolyte combining PEO polymer matrix with succinonitrile plastic crystal and dual lithium salts, where the polymer provides mechanical integrity and the plastic crystal enhances ionic conductivity
Solution Approach 2:
The patent merges the advantages of polymer matrices (mechanical strength) with plastic crystal additives (high ionic conductivity) to create a hybrid electrolyte system that exhibits both properties simultaneously
3Strength
If conventional polymer electrolyte with PEO matrix is used, then mechanical strength is improved, but room temperature ionic conductivity is reduced to orders of magnitude lower than liquid electrolytes
Solution Approach 1:
The patent modifies the polymer electrolyte parameters by incorporating succinonitrile plastic crystal and dual lithium salts, changing the electrolyte's ionic conduction mechanism and dramatically improving room temperature conductivity from 10^-6 S/cm to 10^-4 S/cm
4Reliability
If solvent-free solid electrolytes are created by doping with succinonitrile, then ionic conductivity is improved, but mechanical integrity is lost due to waxy plastic crystal matrix
Solution Approach 1:
The patent formulates a composite electrolyte where succinonitrile plastic crystal is dispersed within a PEO polymer matrix, creating a composite material that leverages the mechanical properties of the polymer and the ionic conductivity of the plastic crystal
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 achieves high ionic conductivity and mechanical strength, leading to improved cycle stability and capacity retention in lithium ion batteries, with specific capacities comparable to liquid electrolyte batteries and reduced interfacial resistance, thus addressing the limitations of previous technologies.
Implementation Method 1
a crosslinkable polyether... Crosslinking the low-molecular-weight prepolymer PEGDA
Implementation Method 2
crosslinkable polyether... UV-induced photopolymerization
Implementation Method 3
doping with succinonitrile (SCN) plastic crystals for lithium ion transport... SCN itself is a poor ionic conductor
Implementation Method 4
rely on the plastic crystal phase of SCN in the PEO/PEGDMA matrix to achieve both sufficiently high ionic conductivity and mechanical strength
Implementation Method 5
the electrolytic solution includes a plasticizer, a crosslinkable polyether, a first lithium salt and a second lithium salt... LiTFSI and LiBOB
Implementation Method 6
organic solvents are customarily used as a means of ionizing the ionic lithium salt
Implementation Method 7
impregnating a cathodic material in the electrolytic solution so as to form the composite cathode... impregnated with an electrolytic solution
Implementation Method 8
reduced interfacial resistance... achieving good contact between the solid electrolyte and the electrodes
Data Source
AI summary
A method of creating a composite cathode for use within a lithium ion battery. The method beginning with the step of preparing an electrolytic solution. The electrolytic solution includes a plasticizer, a crosslinkable polyether, a first lithium salt and a second lithium salt. The method ending with the step of impregnating a cathodic material with the electrolytic solution so as to form the composite cathode.