Carbon Quantum Dot Electrolyte for Stable High-Conductivity Cells
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Solution Overview
Problem
Conventional electrochemical devices face stability and reliability issues due to decomposition and deformation of electrode materials, low ionic conductivity, and side reactions, particularly in lithium-ion batteries, which can lead to explosions and inefficiencies.
Innovation Solution
Development of an electrolyte comprising a salt of carbon quantum dots with a metal cation, having an average diameter of 2 to 12 nanometers and a surface charge of -20 mV or less, which improves ionic conductivity and thermal stability, preventing side reactions and enhancing electrochemical durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 is used as electrolyte to achieve excellent ion mobility and solubility, then ion conductivity is improved, but thermal stability deteriorates and side reactions occur leading to safety issues
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by replacing conventional LiPF6 salts with lithium carboxylate salts (lithium acetate, lithium propionate, lithium butyrate). This parameter change maintains ion conductivity while improving thermal stability and eliminating side reactions that cause safety issues.
Solution Approach 2:
The patent uses simple carboxylate anions (acetate, propionate, butyrate) that are chemically stable and less prone to decomposition. These short-chain carboxylate structures provide sufficient ionic conductivity without the complex decomposition pathways of LiPF6, effectively replacing the problematic electrolyte salt.
2Reliability
If salt concentration is increased to improve ionic conductivity, then ion mobility is enhanced, but viscosity increases and diffusion coefficient decreases
Solution Approach 1:
The patent changes the molecular structure parameter of the electrolyte salt from LiPF6 to lithium carboxylates. The carboxylate anions have different solvation properties and smaller hydrodynamic radii, allowing for optimal ionic conductivity at lower concentrations without excessive viscosity increase, thus maintaining fast lithium ion diffusion.
3Productivity
If conventional electrolyte salts are used to achieve high ion mobility, then electrochemical performance is improved, but electrode material stability deteriorates due to side reactions
Solution Approach 1:
The lithium carboxylate electrolytes create a chemically inert environment toward electrode materials. The carboxylate anions are highly stable and do not participate in side reactions with electrodes, maintaining electrode material stability while still enabling high electrochemical performance through efficient lithium ion transport.
Solution Approach 2:
The simple carboxylate structures (acetate, propionate, butyrate) are inherently stable and resist decomposition. These short-chain carboxylates replace complex electrolyte salts that prone to side reactions, providing a stable chemical environment that protects electrode materials while maintaining electrochemical activity.
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 electrolyte enhances the stability and reliability of electrochemical devices by reducing side reactions and improving ionic conductivity, leading to improved performance and safety.
Implementation Method 1
The electrolyte allows for the formation of a resistive contact between the electrode and the solution through the flow of ions and ion exchange
Implementation Method 2
when the salt concentration increases, the ion conductivity decreases due to the decrease in the diffusion coefficient of the ions
Implementation Method 3
electrolyte comprising a salt of a carbon quantum dot anion and a metal cation having an average diameter in the range of 2 to 12 nanometers (nm) and a surface charge of -20 mV or less
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The present invention relates to an electrolyte for an electrochemical device and preparation method thereof, more particularly to an electrolyte for an electrochemical device including a first electrode, a second electrode spaced apart from the first electrode and an electrolyte filled between the first electrode and the second electrode, wherein the electrolyte comprises a salt form of a carbon quantum dot anion and a metal cation having an average diameter in the range of 2 to 12 nanometers (nm) and a surface potential of -20 mV or less, and preparation method thereof, the electrolyte for an electrochemical device according to the present invention has a very small dissociation energy of anion and cation, and thus improves ionic conductivity. And due to large ion polarization, and high anionic thermochemical / electrochemical stability of the electrolyte, no side reactions occur during device driving and it is possible to build an electrochemical device with greatly improved stability and reliability.