Sodium Silicate Glass Ceramic Electrolyte for Room Temperature Batteries
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Solution Overview
Problem
Current sodium ion-based solid-state electrolytes lack suitable physical and electrical properties at room temperature, and existing lithium-ion batteries face safety hazards due to flammable organic solvents and high lithium costs.
Innovation Solution
Development of glass ceramics with a sodium silicate composition, such as NaxMxSixOx, where M is Gd or Y, exhibiting a conductivity of at least 10−4 Scm−1 at 20° C. and electrochemical stability at a current density of 0.01 mA cm−2 for 100 cycles, produced through a method involving high energy ball milling, heating, and isostatic pressing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional liquid electrolytes with organic solvents are used in Li-ion batteries, then high energy density is achieved, but safety hazards increase due to low flash point and high flammability
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, and transitions from lithium-based to sodium-based chemistry. This fundamental parameter change eliminates flammability while maintaining ionic conductivity through the development of Na3GdSi3O9 glass ceramic with optimized composition and structure.
Solution Approach 2:
The patent employs a composite glass ceramic material combining sodium oxide, gadolinium oxide, and silicon dioxide in specific ratios. This composite structure integrates the benefits of ionic conductivity from sodium silicate with the structural stability and lower flammability characteristics of gadolinium-containing phases.
2Use of energy by moving object
If lithium-based technologies are used to achieve high energy density, then battery performance improves, but cost and environmental concerns increase
Solution Approach 1:
The patent substitutes expensive lithium with abundant and cheaper sodium, which is the sixth most abundant element in the Earth's crust. This material substitution dramatically reduces raw material costs while maintaining functional performance through the development of sodium ion conductive glass ceramics.
3Reliability
If Na-β alumina ceramic electrolytes are used in sodium batteries, then ionic conductivity is achieved, but operating temperature must be maintained at high temperatures (300°C)
Solution Approach 1:
The patent changes the chemical composition from traditional Na-β alumina to a sodium gadolinium silicate glass ceramic system. This compositional change enables room temperature operation by creating a glassy matrix with amorphous pathways for sodium ion conduction, eliminating the need for high temperature operation.
Solution Approach 2:
The patent utilizes the glass transition and amorphous structure formation during cooling from melt. The rapid cooling process creates a glassy phase with disordered atomic structure that provides continuous pathways for ion conduction at room temperature, unlike the crystalline structure of Na-β alumina.
4Productivity
If rare earth silicates Na5MSi4O12 are synthesized using traditional methods, then material is produced, but phase separation and microstructural changes occur
Solution Approach 1:
The patent performs preliminary high-energy ball milling of precursors to achieve homogeneous mixing at the nanoscale before sintering. This pre-mixing action ensures uniform distribution of sodium, gadolinium, and silicon oxides, preventing phase separation during subsequent heating and creating a stable glass ceramic structure.
Solution Approach 2:
The patent employs a multi-stage heating process with periodic temperature increases (e.g., heating to 900°C then 1050°C) followed by controlled cooling. This periodic thermal treatment allows progressive reaction and densification while maintaining compositional stability and avoiding unwanted phase transformations.
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 sodium silicate glass ceramics provide a stable and conductive solid-state electrolyte suitable for room temperature operation, enhancing the safety and efficiency of sodium ion batteries while reducing environmental concerns associated with lithium.
Implementation Method 1
mixing a mixture of precursors comprising sodium, silicon, oxygen and gadolinium for about 6 hours at about 200 rpm in high energy ball mill
Implementation Method 2
heating the mixture to about 900° C. for about 6 hours
Implementation Method 3
heating the pellets for about 6 hours at about 1050° C. with a heating rate of about 5° C. per minute
Implementation Method 4
pressing a resultant powder into pellets by isostatic pressing
Implementation Method 5
it has a conductivity of at least 10−4 Scm−1 at 20° C.
Data Source
AI summary
Materials, methods and uses for sodium silicate solid electrolyte materials, their methods of production, and their use in electrochemical cells. A solid electrolyte has the chemical composition NaxMxSix0x, wherein M is Gd or Y, wherein x is an integer between 1 and 10, characterized in that it has a conductivity of at least 10−4 Scm−1 at 20° C., and is electrochemically stable at a current density of 0.01 mA cm−2 for at least 100 cycles. The glass ceramic has characteristics demonstrating that it is useful as a solid-state electrolyte in sodium ion batteries and in other technologies demanding a stable sodium ion conductor