Organic Lithium Battery Electrolyte Stability
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Solution Overview
Problem
Existing organic lithium batteries face challenges with low cycling stability and high cost due to the solubility of redox organic structures in electrolytes, leading to reduced specific capacity and poor electrochemical performance.
Innovation Solution
The use of a high concentration of lithium salt in combination with a liquid linear or cyclic polyether with a molecular weight of less than 10,000 g/mol in the electrolyte, which restricts the dissolution and diffusion of redox organic structures, improving the battery's electrochemical performance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes with low lithium salt concentration are used, then the electrolyte has good ion conductivity and low viscosity, but the redox organic structures dissolve and diffuse in the electrolyte leading to low cycling stability and reduced specific capacity
Solution Approach 1:
The patent changes the concentration parameter of lithium salt in the electrolyte from conventional low levels (1-1.5 mol/l) to high levels (at least 1.6 mol/l). This parameter change fundamentally alters the electrolyte's interaction with redox organic structures, restricting their dissolution and diffusion while maintaining acceptable ion conductivity, thereby resolving the contradiction between cycling stability and lithium salt concentration
Solution Approach 2:
The patent creates a composite electrolyte system combining high concentration lithium salt with specific solvents (cyclic carbonates like EC, PC, or GC). This composite approach leverages the high dielectric constant and dipole moment of cyclic carbonate solvents to stabilize the high lithium salt concentration, preventing precipitation while restricting redox organic structure dissolution, thus achieving both improved cycling stability and maintained ion conductivity
2Reliability
If high concentration of lithium salt is used in the electrolyte, then the dissolution and diffusion of redox organic structures is restricted improving cycling stability, but the ion conductivity and lithium ion mobility decrease
Solution Approach 1:
The patent optimizes the solvent parameters by selecting cyclic carbonates with high dielectric constants and dipole moments (EC: 90.6, PC: 64.8, GC: 40.9). These parameter changes in solvent properties compensate for the increased viscosity from high lithium salt concentration, maintaining lithium ion mobility while achieving restricted redox organic structure dissolution for improved cycling stability
Solution Approach 2:
The patent form a composite electrolyte using high concentration lithium salt (at least 1.6 mol/l) combined with cyclic carbonate solvents (EC, PC, or GC). The cyclic carbonate component provides high dielectric constant and dipole moment characteristics that maintain ion conductivity despite high salt concentration, while the high salt concentration restricts redox organic structure dissolution, thus resolving the contradiction between cycling stability and lithium ion mobility
3Reliability
If inorganic electrode materials are used, then the batteries have high energy density and good cycling stability, but they exhibit high cost, high toxicity, difficulty of recycling, and risk of explosion
Solution Approach 1:
The patent replaces expensive, toxic, and difficult-to-recycle inorganic electrode materials with organic redox structures that can be derived from renewable resources. These organic materials are inherently safer (no explosion risk), less toxic, and easier to recycle or dispose of, while maintaining good cycling stability through the high concentration electrolyte system, thus resolving the contradiction between reliability and harmful factors
Solution Approach 2:
The patent fundamentally changes the chemical composition parameter from inorganic to organic materials in the electrode. This parameter change transitions the battery system from using geologically-derived inorganic compounds to organically-derived redox structures, eliminating explosion risks associated with inorganic materials while maintaining cycling stability through the optimized high concentration electrolyte system
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
This configuration significantly enhances the stability of specific capacity over numerous cycles and allows for the use of various redox organic structures without modifying their structures, resulting in improved electrochemical performance and reduced costs.
Implementation Method 1
an electrolyte comprising a high concentration of lithium salt... which restricts the dissolution and diffusion of redox organic structures
Implementation Method 2
During the operation of the battery, lithium ions pass from one to the other of the electrodes through the electrolyte
Implementation Method 3
a positive electrode based on redox organic compounds... an organic structure capable of carrying out one or more reversible oxidation/reduction reactions
Data Source
AI summary
Organic lithium batteries are provided having high energy and power densities with a positive electrode based on redox organic compounds and an electrolyte having a high concentration of lithium salt.