Solid-State Electrolyte Powder Formation Without Air Passivation
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Solution Overview
Problem
Solid-state electrolyte powders face issues with air passivation layers forming on their surface, leading to increased interface impedance and reduced cycling performance due to oxidation, which conventional machining methods like grinding or polishing cannot effectively address, especially in the case of inorganic ceramic electrolytes.
Innovation Solution
A method involving the formation of a zirconium compound layer on the inner surface of a container, where a precursor mixture with zirconium source compounds and lithium source compounds is sintered, followed by an aerobic sintering process to produce the solid-state electrolyte powder, which adsorbs excess lithium and prevents passivation layer formation, and a subsequent cleaning process with an acid and alcohol solution to remove any formed passivation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional machining methods like grinding or polishing are used to treat the surface of solid-state electrolyte powder, then the air passivation layer can be removed, but the powder structure cannot be effectively treated and the cycling performance remains reduced
Solution Approach 1:
The patent replaces mechanical treatment methods (grinding, polishing) with a chemical treatment method using hydrochloric acid solution. The acid chemically reacts with and removes the air passivation layer on the powder surface without requiring mechanical contact, thereby solving the problem of ineffective powder treatment while eliminating the passivation layer.
Solution Approach 2:
The patent changes the treatment parameter from mechanical force to chemical concentration. By using a specific concentration range of hydrochloric acid (0.1-30 wt%), the method achieves effective removal of the passivation layer through chemical dissolution rather than mechanical action, improving both treatability and effectiveness.
2Stability of the object's composition
If the surface of inorganic ceramic solid-state electrolyte powder is exposed to air, then oxidation occurs forming a passivation layer, but this increases interface impedance and reduces cycling performance
Solution Approach 1:
The patent applies preliminary action by treating the powder with hydrochloric acid solution immediately after sintering, before the passivation layer can significantly degrade performance. This pre-treatment removes the oxidation layer that forms upon air exposure, preventing the subsequent increase in interface impedance and preserving cycling performance.
Solution Approach 2:
The patent converts the harmful oxidation effect into a beneficial process. The controlled oxidation that forms the passivation layer is subsequently used as a target for acid treatment, where the acid selectively removes the oxidized layer. This two-step process (oxidation followed by acid treatment) transforms the harmful passivation into a removable intermediate that reveals the fresh, high-performance powder surface.
3Reliability
If solid-state electrolytes are used to improve battery safety and energy density, then performance is enhanced, but the formation of air passivation layers on powder surface creates interface impedance issues
Solution Approach 1:
The patent introduces hydrochloric acid solution as an intermediary substance between the solid-state electrolyte powder and the air passivation layer. The acid acts as a mediator that selectively reacts with and removes the passivation layer without damaging the underlying electrolyte powder, thereby eliminating interface impedance while preserving the safety benefits of solid-state electrolytes.
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 method enhances the ionic conductivity of the solid-state electrolyte powder by promoting the formation of a cubic crystal phase and preventing the formation of passivation layers, thereby improving the battery's safety and performance.
Implementation Method 1
the zirconium compound layer on this container can adsorb excess lithium during the sintering process
Implementation Method 2
An aerobic sintering process is performed to form the solid-state electrolyte powder
Implementation Method 3
promoting the formation of a cubic crystal phase
Implementation Method 4
a cleaning process is performed to mix the solid-state electrolyte powder with a cleaning solution to form a mixed solution, in which the cleaning solution includes an acid and an alcohol
Data Source
AI summary
A method of forming a solid-state electrolyte powder includes the following steps. A zirconium compound layer is formed on an inner surface of a container. A precursor mixture is placed on the zirconium compound layer. The precursor mixture includes a first salt group and a second salt group. The first salt group includes zirconium source compound, lanthanum source compound, aluminum source compound, titanium source compound, tantalum source compound, or combinations thereof. The second salt group includes lithium source compound. An aerobic sintering process is performed to form the solid-state electrolyte powder.