Amorphous Sodium Solid Electrolyte for Low-Temperature Densification
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Solution Overview
Problem
Conventional beta-alumina-based solid electrolytes in all-solid-state sodium secondary batteries face issues with material compatibility during high-temperature firing, leading to deteriorated battery characteristics due to reactions between the electrode active material and the solid electrolyte.
Innovation Solution
A solid electrolyte composed of alkali metal oxide and silicon oxide, amorphous in nature, is used, allowing for excellent adhesion to the electrode and enabling densification at temperatures below 200°C, thereby maintaining good battery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional beta-alumina-based solid electrolyte is fired at high temperatures to achieve excellent adhesion and dense electrode structure, then adhesion to electrode is improved and electrode density is improved, but material compatibility deteriorates due to reactions between electrode active material and solid electrolyte
Solution Approach 1:
The patent changes the firing temperature parameter from conventional high temperatures (typically above 900°C for beta-alumina) to low temperatures (below 400°C). This parameter change allows the solid electrolyte to achieve sufficient adhesion and densification without triggering harmful reactions between the electrode active material and the solid electrolyte, thus resolving the contradiction between adhesion strength and material compatibility.
2Volume of stationary object
If conventional beta-alumina-based solid electrolyte is fired at high temperatures to achieve dense electrode structure, then electrode density is improved, but battery characteristics deteriorate due to material reactions
Solution Approach 1:
The patent applies low-temperature firing (below 400°C) instead of conventional high-temperature firing. This parameter change enables the solid electrolyte to achieve adequate densification for good battery performance without causing material reactions that would deteriorate battery characteristics, thus resolving the contradiction between electrode density and reliability.
3Strength
If high-temperature firing is used to achieve excellent adhesion, then adhesion is improved, but choice of electrode active material is limited due to material reactions
Solution Approach 1:
By changing the firing temperature parameter to low temperatures (below 400°C), the patent eliminates thermal reaction constraints between the solid electrolyte and various electrode active materials. This enables broader material selection and greater versatility in electrode design while maintaining adequate adhesion, thus resolving the contradiction between adhesion strength and adaptability.
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 amorphous solid electrolyte with alkali metal oxide and silicon oxide composition ensures excellent adhesion and densification without high-temperature firing, resulting in improved battery performance with high charge and discharge capacities and efficiencies.
Implementation Method 1
the solid electrolyte has excellent adhesion to the electrode
Implementation Method 2
densifiable without being fired at high temperatures
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is a solid electrolyte having excellent adhesion to the electrode and densifiable without being fired at high temperatures and, thus, capable of delivering good battery characteristics. A solid electrolyte for a sodium-ion secondary battery contains an alkali metal oxide and silicon oxide and is amorphous.