Lithium Battery Ionomer for High Voltage Stability

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Solution Overview

Problem

Lithium secondary batteries face challenges in maintaining high temperature and high voltage stability due to electrolyte salt decomposition, leading to corrosion, transition metal elution, and concentration polarization, which reduces cycle life and power efficiency.

Innovation Solution

Incorporating an ionomer with a fluoroalkyl sulfonate substituent in the cathode, anode, or separator of lithium secondary batteries, which acts as a single ion conductor and lithium source, reducing the amount of electrolyte salt and preventing anion-induced side reactions, thereby enhancing ionic conductivity and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrolyte salt is used in high temperature and high voltage environment, then ionic conductivity is maintained, but decomposition occurs leading to corrosion and transition metal elution

Engineering Contradiction:
Improvehigh temperature and high voltage stabilityVSAvoidelectrolyte salt decomposition, corrosion, transition metal elution
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte by introducing fluorinated cyclic carbonate components with specific molecular structures (where a, b, c, d are integers satisfying 1≤a≤4, 1≤b≤4, 1≤c≤4, 1≤d≤4, and a+b+c+d=4-16). This compositional parameter change enables the electrolyte to maintain stability at high temperatures and voltages while preventing decomposition and metal elution.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining fluorinated cyclic carbonate components with specific gravity between 1.8 and 2.2 with other electrolyte solvents. This composite material approach leverages the high dielectric constant and thermal stability of the fluorinated component while maintaining overall ionic conductivity, thereby achieving reliability in extreme conditions without the harmful decomposition effects of conventional electrolytes.

Inventive Principle:
Principle #40Composite materials

2Productivity

If conventional electrolyte is used, then battery operation is maintained, but concentration polarization occurs reducing power efficiency

Engineering Contradiction:
Improvepower efficiencyVSAvoidconcentration polarization
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent modifies the electrolyte's physical and chemical parameters by incorporating fluorinated cyclic carbonate components with specific gravity 1.8-2.2, which have high dielectric constants and unique ionic transport properties. These parameter changes reduce concentration polarization by improving ion distribution and reducing resistance, thereby enhancing power efficiency and reducing energy loss during battery operation.

Inventive Principle:
Principle #35Parameter changes

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 ionomer improves ionic conductivity, prevents transition metal elution, and increases cycle life and power efficiency by reducing concentration polarization, ensuring stability in high temperature and high voltage environments.

Implementation Method 1

an ionomer having a fluoroalkyl sulfonate substituent... secure high ionic conductivity

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

preventing the elution of a transition metal in even high temperature or a high voltage environment

Methodology Applied
Scientific EffectChemical stability:

Implementation Method 3

obtaining high power effects through solving the concentration polarization of the secondary battery

Methodology Applied
Scientific EffectConcentration polarization reduction: Diffusion

Data Source

PatentEP2899794B1Lithium secondary battery
Publication Date: 2020.10.21 LG CHEM LTD
  • EP2899794B1 patent drawingFigure 1
  • EP2899794B1 patent drawingFigure 2
  • EP2899794B1 patent drawingFigure 3~4

AI summary

The present invention relates to a lithium secondary battery including a cathode, an anode, a separator disposed between the cathode and the anode, and a non-aqueous electrolyte. An ionomer is included in at least one element selected from the group consisting of the cathode, the anode, the separator, and the non-aqueous electrolyte.