Composite Metal Halide Solid Electrolyte for Magnesium Ion Conductivity
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Solution Overview
Problem
Magnesium secondary batteries face challenges due to the low ionic conductivity of magnesium ions in solid electrolytes, which is hindered by strong electrostatic interactions with anions, limiting their practical application.
Innovation Solution
A solid electrolyte composed of a composite metal halide containing magnesium, gallium, and indium, with a specific molar ratio, is developed to enhance magnesium-ion conductivity by promoting ion dissociation and expanding the lattice structure, thereby reducing Coulomb repulsion and improving ion migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnesium ions are used in solid electrolytes, then higher theoretical capacity density is achieved, but ionic conductivity is reduced due to strong electrostatic interactions with anions
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by incorporating composite metal halides with specific molar ratios (Mg:Ga:In = 1:(2-a):a where 0 < a ≤ 0.3). This compositional parameter change modifies the lattice structure and electrostatic interactions, enabling magnesium ions to achieve sufficient ionic conductivity (≥1×10^-6 S/cm) while maintaining high theoretical capacity density.
Solution Approach 2:
The patent uses composite metal halide materials combining magnesium, gallium, and indium in specific ratios. This composite material approach creates a lattice structure where the combination of different metal ions optimizes both the capacity density and ionic conductivity, resolving the contradiction between high capacity and sufficient conductivity.
2Reliability
If indium content is increased in the composite metal halide, then ionic conductivity is improved, but structural stability is compromised
Solution Approach 1:
The patent optimizes the indium content parameter within a specific range (molar ratio of In to total Ga+In is 0.05 to 0.30, with a ≤ 0.3 in the formula MgGa2-aInaX8). This parameter optimization ensures sufficient ionic conductivity while preventing excessive lattice distortion that would compromise structural stability. The patent specifies that a satisfies 0 < a ≤ 0.3 to balance conductivity improvement with structural integrity.
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 solid electrolyte achieves improved magnesium-ion conductivity while maintaining structural stability, reducing resistance and ensuring safety, with ionic conductivity values exceeding 1×10−6 S/cm and resistance below 100 Ω·cm2, enhancing the performance of magnesium secondary batteries.
Implementation Method 1
enhance magnesium-ion conductivity by promoting ion dissociation
Implementation Method 2
achieves improved magnesium-ion conductivity while maintaining structural stability, with ionic conductivity values exceeding 1×10−6 S/cm
Implementation Method 3
expanding the lattice structure, thereby reducing Coulomb repulsion and improving ion migration
Implementation Method 4
reducing Coulomb repulsion and improving ion migration
Data Source
AI summary
A solid electrolyte contains a composite metal halide. The composite metal halide contains magnesium, gallium, indium, and a halogen. In the composite metal halide, the molar ratio of indium to the total of gallium and indium is less than 0.2.