Carborane Anion Electrolytes for High-Voltage Magnesium Batteries
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Solution Overview
Problem
Current magnesium (Mg) battery electrolytes face challenges such as dendrite formation, limited energy storage capacity, and corrosion issues due to the use of corrosive chloride ions, which restricts the voltage capacity and stability of Mg-ion batteries.
Innovation Solution
Development of magnesium salts with 10-vertex or 12-vertex carborane anions as electrolytes, which are stable at high electrical potentials and do not contain halide ions, allowing for efficient Mg deposition and stripping, and are compatible with various metal surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Li-ion battery technology is used, then energy storage capacity is limited, but the cost and sustainability are improved
Solution Approach 1:
The patent changes the fundamental parameters of the battery system by switching from Li-ion to Mg-ion chemistry, using divalent Mg ions instead of monovalent Li ions. This parameter change enables twice the charge storage capacity per ion while using abundant, inexpensive magnesium from the earth's crust, thereby simultaneously improving energy storage capacity and cost sustainability.
Solution Approach 2:
The patent employs composite electrolyte systems combining magnesium salts with specific anions (PF6-, BF4-, CF3SO3-) in ether-based solvents. These composite material formulations enable reversible Mg deposition and stripping while preventing dendrite formation, achieving high energy density without sacrificing manufacturing feasibility.
2Quantity of substance
If Mg-based batteries with pure Mg anodes are used, then energy storage capacity is increased, but dendrite formation occurs
Solution Approach 1:
The patent introduces a specially designed electrolyte composition as an intermediary between the Mg anode and the electrochemical reactions. The electrolyte contains magnesium salts with inert anions in ether solvents, which mediate the deposition process to enable reversible Mg stripping and prevent dendrite formation, allowing pure Mg anodes to function reliably.
Solution Approach 2:
The patent changes the electrolyte parameters by using aprotic ether solvents with specific dielectric constants and ionic conductivities. These parameter changes in the electrolyte system enable controlled Mg ion transport and uniform deposition, preventing dendrite formation while maintaining high energy storage capacity with pure Mg anodes.
3Reliability
If Mg salts with common anions (e.g., PF6-, BF4-) are used, then electrolyte conductivity is improved, but anion degradation occurs forming solid films
Solution Approach 1:
The patent identifies and eliminates the problematic anions (PF6-, BF4-, CF3SO3-) that degrade during electrochemical cycling. By removing these unstable anion components from the electrolyte formulation, the patent prevents solid film formation on the Mg anode, enabling long-term reversible Mg deposition and stripping.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by selecting magnesium salts with anions that have appropriate reduction potentials and chemical inertness. This parameter change in anion selection prevents anion degradation and solid film formation while maintaining sufficient ionic conductivity for high-rate Mg ion transport.
4Reliability
If halide ions are present in the electrolyte, then electrochemical stability is improved, but corrosion of non-noble metals occurs
Solution Approach 1:
The patent extracts and removes halide ions from the electrolyte composition to eliminate their corrosive effects on non-noble metals such as aluminum, nickel, and stainless steel. This extraction of harmful halide components allows the use of these metals in battery casings and current collectors, expanding material compatibility while maintaining electrochemical stability through alternative electrolyte formulations.
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 use of carborane-based electrolytes enhances the oxidative stability and conductivity of Mg batteries, enabling reversible Mg deposition and stripping with low overpotentials and improved cycle stability, achieving voltages up to 4.6 V vs. Mg0/+2.
Implementation Method 1
efficient Mg deposition and stripping
Implementation Method 2
reversible Mg deposition and stripping
Implementation Method 3
enhances the oxidative stability and conductivity of Mg batteries
Data Source
AI summary
The present disclosure provides electrolytes for an electrochemical device. In some embodiments, these electrolytes are Mg salts comprising 10-vertex or 12-vertex carborane anions. The present disclosure also provides processes for preparing electrolytes for an electrochemical device. In some embodiments, the process comprises reduction of a reactive cation complexed with a 10-vertex or 12-vertex carborane or 12-vertex borate anion to form metal carborane or borate electrolytes. In some embodiments, the process comprises comproportionating a Mg+2 10-vertex or 12-vertex carborane salt to form a Mg+1 electrolyte comprising a 10-vertex or 12-vertex carborane. The present disclosure further provides electrochemical devices comprising the electrolytes disclosed herein. In some embodiments, the electrochemical device comprises an electrolyte that is stable at an electrical potential greater than 4 V vs Mg0/+2. Also provided herein are heterocyctes bearing the 10, 11, and 12 vertex carborane anions for application as catalyst and battery electrolyte components. The methods of making are also disclosed.