Mixed-Anion Solid Electrolyte for Higher Li-Ion Conductivity
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Solution Overview
Problem
The ionic conductivity of Al-based halide solid electrolytes is low, making it difficult to meet the requirements for solid electrolytes in all-solid-state lithium-ion batteries.
Innovation Solution
A mixed-anion solid electrolyte with the chemical formula LidAl1−cYcCl3−aXb is developed, where Y is selected from certain metal cations and X is selected from various anions. This electrolyte is prepared by a melting reaction method that introduces Li ions and dopes sulfur, oxygen, and other anions into the Al chloride framework, adjusting the potential energy of Li ions and improving ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Al-based halide solid electrolyte is used to replace precious rare earth elements, then raw material cost is reduced, but ionic conductivity becomes low
Solution Approach 1:
The patent creates a composite solid electrolyte system by combining Al-based halide framework with mixed anions (O2−, S2−, F−, Cl−, Br−, I−, BH4−) and metal cations (Y3+, Si4+, Ge4+, Sn4+, Sb5+, Nb5+, Ta5+, Mo6+, W6+). This composite approach allows the material to maintain the cost advantage of Al-based composition while achieving high ionic conductivity through the synergistic effects of multiple anion and cation components, resolving the contradiction between low cost and high performance
Solution Approach 2:
The patent systematically varies the composition parameters including the type and ratio of anions (X and X'), metal cations (Y), and their stoichiometric coefficients (a, b, c) in the formula Li1−aAl1−cYcCl3−aXb to optimize ionic conductivity. By changing these parameters, the activation energy for Li+ migration is reduced while maintaining Al-based composition, thus improving ionic conductivity without increasing raw material cost
2Ease of manufacture
If traditional ball milling method is used to prepare halide solid electrolyte, then preparation is achieved, but preparation time is long and efficiency is low
Solution Approach 1:
The patent replaces the traditional mechanical ball milling process with a solvothermal synthesis method. Instead of using mechanical force to mix and react precursors over extended periods, the invention uses chemical reactions in a solvent under controlled temperature and pressure conditions, dramatically reducing preparation time and improving efficiency while maintaining product quality
Solution Approach 2:
The solvothermal method utilizes phase transitions of the solvent (liquid to supercritical fluid) to enhance reaction efficiency. The solvent penetrates the precursor mixture more effectively under elevated temperature and pressure, facilitating faster and more complete reactions compared to room temperature ball milling, thus improving preparation efficiency
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 introduction of mixed anions significantly improves the ionic conductivity of the Al-based halide solid electrolyte, achieving conductivity up to 10−3 S/cm, which is several orders of magnitude higher than that of LiAlCl4, thereby enhancing the performance of all-solid-state lithium metal batteries.
Implementation Method 1
regulate the potential energy of ions at different sites in the solid, thereby reducing the activation energy during ion migration and increasing the rate of ion migration between different sites
Implementation Method 2
This electrolyte is prepared by a melting reaction method that introduces Li ions and dopes sulfur, oxygen, and other anions into the Al chloride framework
Data Source
AI summary
The invention relates to a mixed-anion solid electrolyte, having the following chemical formula: LidAl1−cYcCl3−aXb, wherein Y is selected from at least one of Si4+, Ge4+, Sn4+, Sb5+, Nb5+, Ta5+, Mo6+, and W6+, and X is selected from at least one of O2−, S2−, F−, Br−, I−, and BH4−; and wherein 0<d≤2, 0<b≤2, 0<a≤2, 0<c<0.75 and charge balance is reached.