Melt-Infiltrated Halide Solid Electrolyte for Battery Conductivity
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Solution Overview
Problem
Conventional solid-state Li-ion batteries face limitations such as low ionic conductivity, especially at low temperatures, low energy density, high costs, and safety concerns due to brittle ceramic electrolytes and potential for dendrite penetration, which restrict their application in high-energy applications like electric vehicles and aerospace.
Innovation Solution
A solid-state Li-ion battery cell design incorporating a melt-infiltration method using a lithium halide compound-based solid electrolyte with a melting temperature of approximately 200°C or less, infiltrated into the anode, cathode, and separator, enhancing ionic conductivity and energy density while improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-state batteries use ceramic electrolytes, then safety is improved, but ionic conductivity deteriorates especially at low temperatures
Solution Approach 1:
The patent changes the physical state of the electrolyte from solid ceramic to liquid halide compound, operating above its melting point (e.g., LiAlCl4 melts at 150°C). This parameter change from solid to liquid state fundamentally improves ionic conductivity while maintaining safety benefits, resolving the contradiction between safety and ionic conductivity.
Solution Approach 2:
The patent uses composite electrode structures where active materials are embedded in conductive matrices (e.g., sulfur in carbon, metal oxides in conductive frameworks). This composite approach enhances overall cell performance and ionic conductivity while maintaining the safety advantages of non-flammable halide electrolytes.
2Quantity of substance
If solid-state batteries are designed with higher energy density, then energy density is improved, but cycle stability deteriorates
Solution Approach 1:
The patent employs high-voltage cathode materials (e.g., LiCoO3, LiNi0.8Co0.1Mn0.1O2 operating at 4.0-4.3V vs. Li/Li+) and anodes with high capacity (e.g., Li metal, Li-Si alloys). These parameter changes in electrode composition and operating voltage enable high energy density while the stable halide electrolyte maintains cycle stability through superior electrochemical stability.
Solution Approach 2:
The patent uses composite electrode structures with high-capacity active materials embedded in conductive matrices, such as sulfur particles in carbon frameworks, metal oxide nanoparticles in conductive polymers, or Li-Si composite anodes. These composite structures maintain structural integrity during cycling while achieving high energy density.
3Ease of manufacture
If melt-infiltration method is used with halide electrolytes, then manufacturing cost is reduced, but manufacturing precision deteriorates due to infiltration control
Solution Approach 1:
The patent utilizes the phase transition of halide electrolytes from solid to liquid above their melting points (e.g., LiAlCl4 at 150°C, Li2MgCl4 at 200°C). The liquid state enables complete infiltration into porous electrodes through capillary action, and subsequent cooling solidifies the electrolyte in place. This phase transition approach simplifies manufacturing while ensuring uniform infiltration, resolving the contradiction between ease of manufacture and infiltration control.
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 approach results in improved ionic conductivity, increased energy density, and enhanced safety by reducing the risk of dendrite formation, making the batteries more suitable for high-energy applications with potentially lower production costs.
Implementation Method 1
a solid electrolyte interposed between the anode and the cathode, the solid electrolyte comprising a melt-infiltration solid electrolyte composition infiltrated in at least a portion of the anode and at least a portion of the cathode; wherein the melt-infiltration solid electrolyte composition comprises a lithium halide compound selected from: Li1+xMgxAl1-xCl4, Li2MgCl4, LiCl, and LiAlCl4, the x ranging between 0.00 and 1.00; and wherein the solid electrolyte is characterized by a melting temperature of approximately 200° C. or less
Data Source
AI summary
A solid-state Li-ion battery cell includes an anode, a cathode, and a solid electrolyte interposed between the anode and the cathode. The anode includes anode active material and the cathode includes cathode active material. The solid electrolyte includes a melt-infiltration solid electrolyte composition infiltrated in at least a portion of the anode and at least a portion of the cathode. The melt-infiltration solid electrolyte composition includes a lithium halide compound selected from: Li1+xMgxAl1-xCl4, Li2MgCl4, LiCI, and LiAICl4. The solid electrolyte is characterized by a melting temperature of approximately 200° C. or less (e.g., in some designs, approximately 150° C. to approximately 156° C.).