Modified Lithium Metal Phosphate Electrolyte for Water Stability
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Solution Overview
Problem
Current solid electrolytes in lithium-air, lithium-water, and hybrid Li-air/Li-water batteries face challenges with poor environmental stability, leading to decreased performance and safety issues due to water exposure, as they dissolve, degrade, or exhibit reduced conductivity.
Innovation Solution
A polycrystalline lithium-ion conductive membrane is modified with a modifying phase, such as metal oxides or phosphates, incorporated into grain boundaries and surfaces, enhancing water resistance and electrical conductivity, while maintaining a hermetic seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used to provide hermetic seal between anode and cathode, then environmental isolation is improved, but environmental stability deteriorates due to dissolution and degradation when exposed to water
Solution Approach 1:
The patent applies composite materials by combining the base polycrystalline lithium metal phosphate electrolyte with modifying phases (metal oxides or phosphates) incorporated into grain boundaries and surfaces. This composite structure provides both hermetic sealing properties and enhanced environmental stability, as the modifying phases create water-resistant barriers at critical interfaces while maintaining the electrolyte's ionic conductivity.
Solution Approach 2:
The patent implements local quality by concentrating the modifying phases specifically at grain boundaries and surfaces rather than uniformly throughout the bulk material. This localized modification targets the regions most susceptible to water attack and degradation, providing enhanced environmental stability at critical interfaces while preserving the overall electrochemical performance of the electrolyte.
2Stability of the object's composition
If modifying phases are incorporated into grain boundaries and surfaces, then environmental stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating the modifying phases into the grain boundaries and surfaces during the initial sintering process rather than requiring subsequent separate treatment steps. The composition is applied to the green body before sintering, allowing the modifying phases to be integrated into the microstructure in a single manufacturing cycle, thus reducing overall process complexity.
Solution Approach 2:
The patent utilizes parameter changes by optimizing the sintering temperature and atmosphere to control the incorporation and distribution of modifying phases. By adjusting these processing parameters, the patent achieves effective grain boundary modification without requiring complex multi-step manufacturing processes, balancing environmental stability improvement with manufacturing simplicity.
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 modified membrane exhibits a lower rate of etching by water, improved electrical conductivity, and increased stability, effectively addressing the environmental stability issues and enhancing the performance of lithium batteries.
Implementation Method 1
the at least one modifying phase is: incorporated into the grain boundaries to form a modified polycrystalline lithium-ion conductive material comprising modified grain boundaries
Implementation Method 2
incorporated into the at least one surface to form a modified surface
Implementation Method 3
a polycrystalline lithium-ion conductive membrane for use as a solid electrolyte
Data Source
AI summary
There is disclosed a polycrystalline lithium-ion conductive membrane for a lithium-air battery that comprises at least one surface, a polycrystalline lithium-ion conductive material comprising grain boundaries, and at least one modifying phase, wherein (a) the at least one modifying phase is incorporated into the grain boundaries to form a modified polycrystalline lithium-ion conductive material comprising modified grain boundaries, (b) the at least one modifying phase is incorporated into the at least one surface to form a modified surface, or both (a) and (b). Various lithium based batteries, including lithium ion, lithium-air, and lithium-water batteries are disclosed, as well as methods for modifying the polycrystalline lithium-ion conductive membrane to allow it to be used in such battery applications.