Aqueous Secondary Battery High Molarity Electrolyte
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Solution Overview
Problem
Aqueous electrolyte systems for secondary batteries face limitations in achieving high voltage and energy density due to the low decomposition voltage of water, leading to poor performance compared to non-aqueous systems.
Innovation Solution
An aqueous secondary battery design incorporating a metal salt solution with specific metal ions and atomic group ions at high molarity, forming a crystalline hydrate that enhances ion conductivity and stability, allowing for a wider electrochemical stability window and improved charge/discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aqueous electrolyte system is used, then stability and cost-effectiveness are improved, but voltage and energy density are significantly lowered
Solution Approach 1:
The patent changes the concentration parameter of the aqueous electrolyte to high molarity (5-40 m), which fundamentally alters the electrochemical properties of the system. This high concentration regime enables the formation of crystalline hydrates and contact ion pairs that expand the electrochemical stability window beyond the conventional 1.23 V water decomposition limit, achieving voltages up to 4 V while maintaining aqueous stability
Solution Approach 2:
The patent creates a composite electrolyte system consisting of water, high-concentration metal salts, and形成的 crystalline hydrate structures. This composite approach combines the stability of aqueous systems with the high voltage characteristics needed for energy-dense batteries, achieving a synergistic effect that overcomes the inherent limitations of pure water-based electrolytes
2Reliability
If an aqueous electrolyte system is used, then stability and cost-effectiveness are improved, but energy density is significantly lowered
Solution Approach 1:
By changing the concentration parameter to high molarity (5-40 m) and controlling the formation of crystalline hydrates and contact ion pairs, the patent achieves a mole fraction of contact ion pairs greater than 50%, which significantly improves ion conductivity (≥40 mS/cm) and enables higher energy density while maintaining aqueous stability
Solution Approach 2:
The patent utilizes the phase transition of the electrolyte system where high-concentration metal salts form crystalline hydrate structures in the aqueous solution. This phase transition creates a structured electrolyte environment that enhances ion conductivity and stabilizes high-voltage operation, thereby improving energy density without sacrificing the inherent stability of aqueous systems
3Power
If high concentration metal salt is used to improve ion conductivity, then electrochemical stability window is expanded, but solution viscosity increases
Solution Approach 1:
The patent exploits the phase transition phenomenon where high-concentration metal salts form crystalline hydrates in the aqueous electrolyte. This crystalline structure formation organizes the ions and water molecules in a structured arrangement that maintains low viscosity even at high concentrations (5-40 m), while simultaneously expanding the electrochemical stability window to enable high-voltage operation
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 exhibits high voltage, improved energy density, and stable charge/discharge performance, overcoming the limitations of conventional aqueous systems while maintaining cost-effectiveness.
Implementation Method 1
The aqueous electrolyte may include a crystalline hydrate, and the crystalline hydrate may include at least a portion of the metal ions and/or the atomic group ions that constitute a coordination with water molecules
Implementation Method 2
A mole fraction of the contact ion pair relative to the aggregated cation-anion pair of the metal ion and the atomic group ion forming the crystalline hydrate may be greater than or equal to about 50% based on a total amount of the metal ions and the atomic group ions that are ionized in the aqueous electrolyte
Implementation Method 3
The aqueous electrolyte may have ion conductivity of greater than or equal to about 40 mS/cm
Data Source
AI summary
An aqueous secondary battery including: a positive electrode; a negative electrode; a separator; and an aqueous electrolytic solution including water and a metal salt represented by Chemical Formula 1 AxDy and having molality of about 5 M to about 40 M wherein in Chemical Formula 1, A is at least one metal ion selected from a sodium ion, a potassium ion, a magnesium ion, a calcium ion, a strontium ion, a zinc ion, or a barium ion, D is at least one type of atomic group ion selected from Cl−, SO42−, NO3−, ClO4−, SCN−, CF3SO3−, C4F3SO3−, (CF3SO2)2N−, AlO2−, AlCl4−, AsF6−, SbF6−, BR4−, and PO2F2−, and 0<x≤2, and 0<y≤2.