Solid Polymer Electrolyte for High Voltage Lithium Metal Batteries
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Solution Overview
Problem
Lithium secondary batteries face limitations in energy density and electrolyte stability at high voltages and temperatures due to the decomposition of typical electrolytes, which restricts their state of charge and operational temperature range.
Innovation Solution
The use of a solid polymer electrolyte with high crystallinity, ionic conductivity, and the presence of both cationic and anionic diffusing ions, including lithium, which is integrated between the anode and cathode in a lithium battery, enabling stable operation at high voltages and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If typical electrolytes are used in lithium secondary batteries, then the battery can operate at reasonable voltages, but the electrolyte decomposes at high voltages and limits battery life
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by incorporating solid polymer electrolyte components (such as PEO, PVDF, PMMA) with specific functional groups that provide both high voltage stability and high lithium ion conductivity. This compositional parameter change allows the electrolyte to maintain stability at voltages above 4.0V while achieving satisfactory state of charge levels.
Solution Approach 2:
The patent uses composite electrolyte systems combining solid polymer matrices with lithium salts (LiPF6, LiBF4, LiTFSI) and potentially liquid electrolyte additives. This composite approach leverages the voltage stability of solid polymers while incorporating components that enhance ionic conductivity and lithium ion transport, resolving the contradiction between stability and charge capacity.
2Adaptability or versatility
If typical electrolytes are used in lithium secondary batteries, then the battery can function at standard temperatures, but the temperature range of useful performance is limited
Solution Approach 1:
The patent modifies the physical and chemical parameters of the electrolyte by selecting solid polymer materials with appropriate glass transition temperatures and melting points. By adjusting polymer chain flexibility, molecular weight, and crystallinity parameters, the electrolyte maintains ionic conductivity across an expanded temperature range while preserving voltage stability.
Solution Approach 2:
The patent creates local regions within the electrolyte with different properties - amorphous regions that provide ionic conductivity pathways and crystalline regions that provide structural stability. This local quality differentiation allows the electrolyte to maintain reliability across varying temperatures while adapting its conductivity properties to local environmental conditions.
3Ease of manufacture
If conventional electrode fabrication processes are used, then electrodes can be manufactured with standard properties, but several manufacturing steps are required
Solution Approach 1:
The patent merges the electrode fabrication process with electrolyte integration by incorporating solid polymer electrolyte components directly into the electrode slurry mixture. This combining of previously separate steps (electrode manufacturing and electrolyte assembly) simplifies the overall manufacturing process while maintaining precise control over electrode properties through standardized slurry preparation and coating techniques.
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
This configuration enhances the battery's energy density, stability, and operational range, allowing for efficient lithium cycling and extended battery life by maintaining ionic conductivity and preventing electrolyte decomposition at high voltages and temperatures.
Implementation Method 1
a solid ionically conductive polymer material with high conductivity over a wide range of temperatures
Implementation Method 2
The solid polymer electrolyte further comprises: a crystallinity greater than 30%; a melting temperature; a glassy state
Implementation Method 3
wherein at least one diffusing ion is mobile in the glassy state
Data Source
AI summary
A battery having a lithium metal anode, a solid polymer electrolyte and a cathode material enabling high voltage discharge.