Transparent Solid-State Separators for Dendrite-Resistant Li-Ion Cells
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Solution Overview
Problem
Conventional solid electrolytes for rechargeable Li+ ion batteries suffer from defects, pores, and inhomogeneities, which can lead to the formation of Li-dendrites, limiting their commercial application and efficiency.
Innovation Solution
Development of a polycrystalline Li+ ion-conducting separator with a grain size less than 20 μm, capable of transmitting greater than 30% of incident light at specific wavelengths, made using methods such as sintering, hot isostatic pressing, or spark plasma sintering, and incorporating materials like oxides, sulfides, or borohydrides to enhance conductivity and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If conventional solid electrolytes are used, then battery weight and volume are reduced, but defects and inhomogeneities form which lead to Li-dendrite growth
Solution Approach 1:
The patent applies parameter changes by controlling sintering temperature (900-1100°C), sintering time (1-24 hours), and pressure (0.1-10 GPa) to transform the electrolyte material from a defective state to a dense, uniform state. These parameter adjustments eliminate pores and inhomogeneities while maintaining the solid electrolyte's weight advantage over liquid electrolytes
Solution Approach 2:
The patent uses composite materials by combining lithium-containing ceramic particles with binders and optionally conductive additives to create a solid electrolyte that is both mechanically robust and free from defects. This composite approach allows tuning of density and uniformity while maintaining the inherent benefits of solid electrolytes
2Productivity
If solid electrolytes are used, then gravimetric and volumetric energy density increase, but manufacturing precision is required to eliminate defects
Solution Approach 1:
The patent applies preliminary action by performing multiple preprocessing steps including particle size classification, mixing with binders, and shaping into desired forms before sintering. These preliminary actions ensure uniform distribution of materials and proper green body formation, which are critical for achieving defect-free dense electrolytes after sintering
Solution Approach 2:
The patent uses parameter changes in the sintering process (temperature, time, pressure, atmosphere) to transform the green body into a dense, defect-free electrolyte. By optimizing these parameters, the patent achieves high energy density electrolytes without manufacturing defects that would compromise performance
3Ease of manufacture
If liquid electrolytes are used, then ease of manufacture is maintained, but flammability and chemical incompatibility problems occur
Solution Approach 1:
The patent applies this principle by using simple, readily available ceramic precursor materials and standard sintering equipment to manufacture solid electrolytes. The process replaces complex liquid electrolyte formulations with a straightforward ceramic processing approach that is both safe and manufacturable using conventional techniques
Solution Approach 2:
The patent uses inert atmosphere sintering to prevent unwanted chemical reactions during electrolyte fabrication. By conducting sintering in controlled atmospheres (nitrogen, argon, or vacuum), the patent eliminates oxidation and other harmful reactions, ensuring electrolyte safety while maintaining manufacturing simplicity
4Ease of manufacture
If solid electrolytes with large grain size are used, then manufacturing is easier, but Li-dendrite formation increases
Solution Approach 1:
The patent applies parameter changes by controlling sintering temperature and time to achieve optimal grain size (1-10 μm). This parameter optimization balances manufacturing ease with dendrite resistance, as the controlled grain growth during sintering creates a uniform microstructure that prevents dendrite formation while remaining manufacturable
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 solution provides a defect-free, high-conductivity Li+ ion-conducting separator that improves the performance and safety of rechargeable batteries by reducing Li-dendrite formation and enhancing energy density.
Implementation Method 1
an electrolyte physically separates and electrically insulates the positive and negative electrodes while also providing a conduction medium for Li+ ions
Implementation Method 2
made using methods such as sintering, hot isostatic pressing, or spark plasma sintering
Implementation Method 3
made using methods such as sintering, hot isostatic pressing, or spark plasma sintering
Implementation Method 4
made using methods such as sintering, hot isostatic pressing, or spark plasma sintering
Data Source
AI summary
Provided herein are detect-free solid-state separators which are useful as Li| ion-conducting electrolytes in electro-chemical cells and devices, such as, but not limited to, rechargeable batteries. In some examples, the separators have a Li+ ion-conductivity greater than 1*10−3 S/cm at room temperature.