Li-PS4-BH4 Solid Electrolyte Purification for Stable Battery Cycling
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Solution Overview
Problem
The use of solid electrolytes containing large amounts of raw materials or impurities leads to a decrease in cycle characteristics due to electrochemical instability, causing oxidation or reduction during changes in electric potential.
Innovation Solution
A solid electrolyte comprising a Li, PS4− structure and a BH4− structure, with specific NMR and DSC conditions, is synthesized by mechanical energy treatment and heat treatment of a sulfide and hydride solid electrolyte mixture, resulting in a stable electrolyte with controlled impurity and raw material content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is synthesized from raw materials, then the electrolyte can be produced, but raw materials and impurities remain causing electrochemical instability and decreased cycle characteristic
Solution Approach 1:
The patent applies preliminary action by performing heat treatment at 100°C to 200°C before final electrolyte formation to remove residual raw materials and impurities. This pre-treatment step eliminates sources of electrochemical instability before the electrolyte is assembled into the battery, preventing cycle characteristic degradation.
Solution Approach 2:
The patent utilizes parameter changes by controlling the heat treatment temperature range (100°C to 200°C) and monitoring NMR peak areas to ensure complete removal of raw materials. By adjusting these parameters, the electrolyte achieves high purity while maintaining the desired Li, PS43−, and BH4− structures for optimal electrochemical stability.
2Ease of manufacture
If the solid electrolyte contains remaining raw materials or impurities, then production is simpler, but oxidation or reduction occurs during electric potential changes
Solution Approach 1:
The patent applies preliminary action by performing heat treatment at 100°C to 200°C before final electrolyte formation to remove residual raw materials and impurities. This pre-treatment step eliminates sources of electrochemical instability before the electrolyte is assembled into the battery, preventing cycle characteristic degradation.
Solution Approach 2:
The patent utilizes parameter changes by controlling the heat treatment temperature range (100°C to 200°C) and monitoring NMR peak areas to ensure complete removal of raw materials. By adjusting these parameters, the electrolyte achieves high purity while maintaining the desired Li, PS43−, and BH4− structures for optimal electrochemical stability.
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 electrolyte stabilizes the cycle characteristics by minimizing oxidation and reduction, maintaining electrochemical stability and ion conductivity, thus enhancing battery performance.
Implementation Method 1
The raw material and the impurity are electrochemically unstable, generally, and therefore, the change in electric potential easily causes oxidation or reduction
Implementation Method 2
In an 11B-NMR measurement, an integral area of a peak α that has a top in a range of 42 ppm±1 ppm is equal to or more than 50% of a total of integral areas of all peaks
Implementation Method 3
In a temperature raising step of a DSC measurement, a heat capacity at an endothermic peak that appears in a range of 115° C.±10° C. is less than 30 J/g
Data Source
AI summary
A solid electrolyte includes Li, a PS43− structure, and a BH4− structure. The following conditions (i) to (iii) are satisfied. Condition (i): In an 11B-NMR measurement, an integral area of a peak α that has a top in a range of 42 ppm±1 ppm is equal to or more than 50% of a total of integral areas of all peaks. Condition (ii): In a 31P-NMR measurement, an integral area of a peak β that has a top in a range of 90.5 ppm±1 ppm is equal to or more than 50% of a total of integral areas of all peaks. Condition (iii): In a temperature raising step of a DSC measurement, a heat capacity at an endothermic peak that appears in a range of 115° C.±10° C. is less than 30 J/g.