Aqueous Electrolyte Freezing Prevention in Pseudo-Capacitors
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Solution Overview
Problem
Aqueous electrolytes used in pseudo-capacitors face freezing issues in low-temperature environments, limiting their operational stability and performance in terms of energy and power density.
Innovation Solution
Incorporating a certain concentration of lithium salt and a zwitterionic compound, such as betaine, into the aqueous electrolyte to prevent freezing and enhance stability, with a lithium salt concentration of 6 molal and zwitterionic compound concentration between 3 to 10 molal, ensuring the electrolyte remains operational at -30 °C or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an aqueous electrolyte is used in a pseudo-capacitor, then the internal resistance is reduced and output characteristics are improved, but the electrolyte freezes in low-temperature environments, reducing the utilization range
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous electrolyte by adding specific concentrations of lithium salts (0.1-10 mol/L) and zwitterionic compounds (0.1-5 mol/L). This compositional modification lowers the freezing point of the electrolyte while maintaining its ionic conductivity, enabling the pseudo-capacitor to operate reliably at temperatures of -30°C or lower without freezing, thus resolving the contradiction between low-temperature stability and power output characteristics
Solution Approach 2:
The patent creates a composite electrolyte system by combining aqueous solvent, lithium salts, and zwitterionic compounds into a multi-component formulation. The lithium salts (such as LiClO4, Li2SO4, LiNO3) provide ionic conductivity, while the zwitterionic compounds (such as betaine, phosphocholine) lower the freezing point and enhance stability. This composite approach maintains high power output characteristics while achieving excellent low-temperature operational reliability
2Reliability
If the concentration of lithium salt and zwitterionic compound is increased to prevent freezing, then low-temperature stability is improved, but the viscosity may increase and conductivity may decrease
Solution Approach 1:
The patent optimizes the concentration parameters within specific ranges: lithium salt at 0.1-10 mol/L and zwitterionic compound at 0.1-5 mol/L. Within these ranges, the electrolyte achieves sufficient freezing point depression for low-temperature stability while maintaining adequate ionic conductivity. The synergistic interaction between the two components ensures that viscosity increases are minimized and conductivity is preserved, resolving the contradiction between reliability and power
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 solution significantly improves the low-temperature stability, charging/discharging efficiency, energy density, and power density of pseudo-capacitors by preventing freezing and maintaining electrochemical performance in cryogenic conditions.
Implementation Method 1
the electrolyte is not frozen even in a cryogenic environment
Implementation Method 2
since the ions and electrons required for oxidation and reduction must move at high speed in the electrolyte and the electrode during charging/discharging
Implementation Method 3
pseudo-capacitors using the principle of electrochemical faradaic reaction
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An aqueous electrolyte for a pseudo-capacitor and a pseudo-capacitor comprising the same, and more particularly an aqueous electrolyte for a pseudo-capacitor comprising an aqueous solvent, and a certain concentration or more of a lithium salt and a zwitterionic compounds, and a pseudo-capacitor comprising the aqueous electrolyte described above.