Molten-Salt Titanium Redox Flow Battery for Higher Current Density
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Solution Overview
Problem
Vanadium ion redox flow batteries face issues with low solubility of active materials in aqueous electrolytes, leading to low current density extraction.
Innovation Solution
A redox flow battery using molten salts as electrolytes, containing specific titanium ions (trivalent, tetravalent, and divalent) in a positive and negative electrode electrolyte, with diaphragms allowing ion permeation, enabling high current density extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aqueous solution is used as electrolyte, then the battery structure is simple and easy to manufacture, but the active material solubility is low and current density is low
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid (aqueous solution) to molten salt state by raising the temperature above the melting point. This parameter change enables the electrolyte to dissolve and transport a much higher concentration of active materials (metal ions), thereby achieving high current density while maintaining manufacturing feasibility through a straightforward heating approach.
Solution Approach 2:
The patent utilizes the phase transition of the electrolyte from liquid to molten salt state. By heating the electrolyte mixture (containing metal halides and flux) above its melting point, the system transitions to a molten state that provides superior ionic conductivity and active material solubility, enabling high current density extraction without complex manufacturing processes.
2Ease of manufacture
If aqueous solution is used as electrolyte, then the manufacturing cost is low, but the active material solubility is low
Solution Approach 1:
The patent changes the temperature parameter to maintain the electrolyte in a molten salt state, enabling high active material solubility. The electrolyte composition (metal halide + flux) is designed to melt at a specific temperature, and by operating above this temperature, the system achieves high concentrations of dissolved metal ions without requiring expensive materials or complex processing.
Solution Approach 2:
The patent uses a flux (such as LiCl-KCl eutectic mixture) as a solvent medium that mimics the properties of aqueous solutions in terms of ionic conductivity but operates at elevated temperatures. This flux-based molten salt system provides a cost-effective alternative to expensive high-solubility electrolyte formulations while enabling high active material concentrations.
3Reliability
If vanadium ion redox flow battery is used, then the battery structure is established, but the current density that can be extracted is low
Solution Approach 1:
The patent changes the electrolyte state from liquid to molten salt by heating, which fundamentally alters the ionic mobility and solubility characteristics. This parameter change enables the battery to achieve high current density (10-100 times higher than conventional aqueous systems) while maintaining the established redox flow battery structure with external reservoirs and flow circulation.
Solution Approach 2:
The patent employs a composite electrolyte system consisting of metal halides (providing active materials) dissolved in a flux (LiCl-KCl eutectic mixture). This composite molten salt electrolyte combines the benefits of high ionic conductivity from the flux with high active material solubility from the metal halide, enabling high current density extraction while maintaining structural reliability.
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 battery achieves a higher current density and electromotive force compared to vanadium ion batteries, reducing the need for additional heating and minimizing material costs.
Implementation Method 1
a diaphragm interposed between the positive electrode and the negative electrode
Implementation Method 2
the positive electrode electrolyte contains a trivalent titanium ion and a tetravalent titanium ion, and the negative electrode electrolyte contains a divalent titanium ion and a trivalent titanium ion
Implementation Method 3
charged and discharged by supply of a positive electrode electrolyte and a negative electrode electrolyte to a battery cell including a positive electrode, a negative electrode
Data Source
AI summary
A redox flow battery that is charged and discharged by supply of a positive electrode electrolyte and a negative electrode electrolyte to a battery cell including a positive electrode, a negative electrode, and a diaphragm interposed between the positive electrode and the negative electrode, wherein the positive electrode electrolyte and the negative electrode electrolyte are molten salts, the positive electrode electrolyte contains a trivalent titanium ion and a tetravalent titanium ion, and the negative electrode electrolyte contains a divalent titanium ion and a trivalent titanium ion.