Microemulsion Electrolytes for Wider Voltage Aqueous Cells
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Solution Overview
Problem
Existing electrolyte compositions for electrochemical energy storage devices, such as batteries and supercapacitors, face limitations including a narrow electrochemical stability window, low conductivity, and high costs, which restrict their performance and compatibility with various electrochemically active species.
Innovation Solution
The development of a microemulsion electrolyte composition comprising an aqueous phase and a water-immiscible phase, which can be configured as an oil-in-water or bicontinuous microemulsion, to enhance conductivity and electrochemical stability, allowing for the use of electrochemically active species with potentials beyond the stability window of bulk water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is used as an electrolyte solvent, then cost is reduced and safety is improved, but the electrochemical stability window is limited to 1.23 V
Solution Approach 1:
The patent uses a composite electrolyte system combining water-immiscible ionic liquid and water phase, creating a two-phase microemulsion structure that leverages the advantages of both components: ionic liquid provides wide electrochemical stability window while water provides low cost and high safety
Solution Approach 2:
The patent introduces a surfactant as an intermediary substance that enables stable mixing of water and water-immiscible ionic liquid, allowing the two phases to form a stable microemulsion structure that would otherwise be immiscible
2Stability of the object's composition
If non-aqueous solvents are used to extend the electrochemical stability window, then voltage range is improved, but cost increases and toxicity increases
Solution Approach 1:
The patent creates a composite electrolyte combining ionic liquid and water in a microemulsion structure, achieving wide electrochemical stability window comparable to pure non-aqueous solvents while incorporating water to reduce cost and toxicity
Solution Approach 2:
The patent changes the physical state and distribution parameters by forming a microemulsion with specific phase ratios and droplet size distributions, enabling the electrolyte to achieve both wide voltage window and reduced cost through water incorporation
3Reliability
If salt concentration in aqueous solution is increased to improve conductivity, then charge conductivity is improved, but solubility limit is exceeded
Solution Approach 1:
The patent segments the electrolyte into two distinct phases: water-immiscible ionic liquid phase and water phase, with salts primarily dissolved in the water phase. This segmentation allows high salt concentration in the water phase without affecting the stability of the ionic liquid phase, achieving high conductivity while maintaining solubility limits
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 microemulsion electrolyte composition achieves a conductivity of more than 0.1 mS·cm−1 and an electrochemical stability window greater than 1.23 V, enabling efficient operation of electrochemical cells at higher voltages without water splitting, thus improving the performance and versatility of electrochemical energy storage devices.
Implementation Method 1
Electrochemical systems, in particular batteries, need an electrolyte which can facilitate dissolution and migration of ions and electrochemically active species
Implementation Method 2
Water can be oxidised to form oxygen gas and reduced to form hydrogen gas (commonly referred to as water splitting) at a potential of 1.23V: 2H2O→O2+2H2E°=+1.23V
Data Source
AI summary
Disclosed are electrolyte compositions for electrochemical devices, where the electrolyte compositions comprise a microemulsion and where the microemulsion comprises an aqueous phase and a water-immiscible phase. Also disclosed are microemulsion electrolyte compositions for electrically rechargeable electrochemical energy storage devices, including ion batteries (such as lithium ion, sodium ion, magnesium ion, calcium ion, and aluminium ion batteries), redox flow batteries and supercapacitors.