Complex Metal Halide Electrolyte for Low-Temperature Solid-State Synthesis
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Solution Overview
Problem
Current solid electrolyte materials for solid-state lithium batteries face challenges such as high synthesis temperatures, brittleness, safety concerns, and limited ionic conductivity, particularly in halide and sulfide materials, which hinder their mass production and performance.
Innovation Solution
A solid ion conductive material comprising a complex metal halide, formed through a process that includes ammonium halide and metal compounds, allowing for improved purity, bulk ion conductivity, and electrochemical stability, suitable for use in solid-state lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-energy ball milling-based solid-state synthesis methods are used to produce halide solid electrolytes, then the materials can be synthesized, but the process faces challenges for mass production and requires expensive binary halide reactants and high-temperature annealing
Solution Approach 1:
The patent changes the synthesis parameters by using a solvothermal method at moderate temperatures (100-200°C) instead of high-temperature annealing (>1000°C), and employs simple lithium halide and metal oxide reactants instead of expensive binary halide reactants, thereby improving ease of manufacture while maintaining productivity
Solution Approach 2:
The patent replaces the mechanical ball milling process with a solvothermal chemical synthesis method, substituting mechanical energy with thermal and chemical energy to achieve the same synthesis goal with better scalability for mass production
2Device complexity
If sulfide materials are used to achieve high ionic conductivity, then ICRT can be as high as 25 mS/cm, but the materials tend to have poor electrochemical stability and cause safety concerns due to the risk of releasing toxic H2S gas when accidentally reacting together with water and heat
Solution Approach 1:
The patent uses complex metal halide composite materials that combine the high ionic conductivity benefits of sulfides with the electrochemical stability and safety of halide compounds, achieving both high ICRT (>1 mS/cm) and resistance to H2S release through the composite structure
Solution Approach 2:
The patent employs stable, non-toxic metal oxide precursors (such as TiO2, ZrO2, HfO2) that form stable complex halide structures, replacing unstable sulfide materials that release toxic H2S gas, thereby eliminating the harmful effect while maintaining functionality
3Reliability
If oxide-based materials are used to ensure safety and good chemical and electrochemical stability, then the materials are typically dense, rigid, and brittle with ionic conductivity up to 1.0 mS/cm at room temperature, but the synthesis uses high temperatures that are above 1000-1200° C
Solution Approach 1:
The patent changes the synthesis temperature parameter from high-temperature (>1000°C) oxide synthesis to moderate-temperature (100-200°C) solvothermal processing of metal oxides and lithium halides, thereby maintaining electrochemical stability while dramatically reducing energy consumption and equipment requirements
Data Source
AI summary
A solid ion conductive material can include a complex metal halide. The complex metal halide can include at least one alkali metal element. In an embodiment, the solid ion conductive material including the complex metal halide can be a single crystal. In another embodiment, the ion conductive material including the complex metal halide can be a crystalline material having a particular crystallographic orientation. A solid electrolyte can include the ion conductive material including the complex metal halide.