Ionic Liquid Electrolyte for Reversible Magnesium Battery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Developing electrolytes for magnesium batteries that support reversible magnesium stripping/deposition and are stable against electrode corrosion within desired electrical potential windows has been challenging, as common magnesium salts and solvents decompose or induce corrosion, limiting their electrochemical stability.
Innovation Solution
An electrolyte composition comprising an ionic liquid with an organic cation and a boron cluster anion, along with a magnesium salt of a boron cluster anion, which does not require ether solvents, thereby preventing decomposition and corrosion, and maintaining stability at electrical potentials exceeding 3 V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common magnesium salts and polar aprotic solvents are used as electrolytes, then the electrolyte can support magnesium ion conduction, but they decompose at the magnesium anode surface creating an impermeable layer that prevents reversible magnesium stripping/deposition
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using Grignard reagents and magnesium organohaloaluminates instead of common magnesium salts and polar aprotic solvents. This parameter change allows the electrolyte to support reversible magnesium stripping/deposition without forming an impermeable decomposition layer at the magnesium anode surface.
Solution Approach 2:
The patent employs composite electrolyte systems combining Grignard reagents with magnesium organohaloaluminates, or magnesium borohydride with boron cluster anion salts. These composite materials work synergistically to provide both reversible magnesium stripping/deposition and prevent anode surface decomposition, resolving the contradiction between reliability and compositional stability.
2Reliability
If Grignard reagents and magnesium organohaloaluminates are used as electrolytes, then reversible magnesium stripping/deposition is supported, but they are corrosive to non-noble metal cathodic current collectors at electrical potentials greater than 2.5 V
Solution Approach 1:
The patent introduces magnesium borohydride and boron cluster anion salts as intermediary substances that mediate between the Grignard reagents/magnesium organohaloaluminates and the cathodic current collector. These intermediaries provide protective effects that prevent corrosion of non-noble metal current collectors at high electrical potentials while maintaining reversible magnesium stripping/deposition.
Solution Approach 2:
The patent creates composite electrolyte systems where Grignard reagents or magnesium organohaloaluminates are combined with magnesium borohydride or boron cluster anion salts. This composite approach allows the system to maintain the beneficial property of reversible magnesium stripping/deposition while the boron-containing components provide protection against corrosion of cathodic current collectors at potentials exceeding 2.5 V.
3Reliability
If ether solvents are used in electrolytes with high electrochemical stability magnesium salts, then magnesium metal compatibility is achieved, but the ether solvent undergoes electrochemical oxidation at about 3.5 V, limiting the electrochemical stability window
Solution Approach 1:
The patent extracts or removes the ether solvent component from the electrolyte system by using ionic liquids as the primary solvent medium. This elimination of ether solvents prevents their electrochemical oxidation at 3.5 V, thereby extending the electrochemical stability window while maintaining magnesium metal compatibility through the use of ionic liquid-based electrolytes with high electrochemical stability magnesium salts.
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 electrolyte composition enables good magnesium conductivity, reversible magnesium stripping/deposition, and improved safety by eliminating volatility and flammability, while maintaining electrochemical stability and preventing corrosion, enhancing the performance and safety of magnesium batteries.
Implementation Method 1
The electrolyte composition includes an ionic liquid of the formula GpA... and a magnesium salt of the formula MgEyA′q... enables good magnesium conductivity
Implementation Method 2
electrolytes based on magnesium borohydride or magnesium salts of boron cluster anions (including carboranyl anions) have shown the ability to support reversible magnesium stripping/deposition, with high oxidative stability at electrical potentials exceeding 3.5 V
Data Source
AI summary
An electrolyte composition for a magnesium electrochemical cell includes a magnesium salt dissolved in an ionic liquid. The ionic liquid includes an organic cation and a first boron cluster anion. The magnesium salt has a magnesium cation and a second boron cluster anion. The magnesium electrochemical cell includes an anode that contains elemental magnesium when charged, a cathode suitable for magnesium insertion or deposition, and the aforementioned electrolyte composition that is in ionic communication with the anode, the cathode, or both.