Propionate Electrolyte Composition for Wide-Temperature Li Batteries

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Solution Overview

Problem

Lithium secondary batteries face challenges in maintaining sufficient capacity and life characteristics, especially under severe temperature conditions such as low or high temperatures, due to limitations in electrolyte performance.

Innovation Solution

The development of an electrolyte for lithium secondary batteries using a non-aqueous organic solvent comprising propionate and carbonate solvents, along with lithium salts like lithium hexafluorophosphate and lithium bisfluorosulfonylimide, which improves ion conductivity and stability, enhancing low-temperature capacity and high-temperature life characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used, then the battery can operate at normal temperatures, but the capacity characteristics and life characteristics deteriorate under severe temperature conditions

Engineering Contradiction:
Improvecapacity characteristics and life characteristicsVSAvoidsevere temperature conditions
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent modifies the chemical composition parameters of the electrolyte by incorporating specific additives (cyclic carbonate-based compounds, fluorine-substituted carbonate-based compounds, sultone-based compounds, cyclic sulfate-based compounds, cyclic sulfite-based compounds, borate-based compounds, and phosphate-based compounds) at controlled concentrations (0.01 wt% to 15 wt% each). This parameter optimization enables the electrolyte to maintain stable ionic conductivity and protective film formation across extreme temperature ranges from -30°C to 60°C, directly improving reliability under severe temperature conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining multiple solvent types (cyclic carbonates, chain carbonates, carboxylic acid esters) with various additive compounds. This composite formulation synergistically enhances both low-temperature fluidity and high-temperature stability, allowing the battery to maintain capacity characteristics and life characteristics across the full temperature range of -30°C to 60°C

Inventive Principle:
Principle #40Composite materials

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 proposed electrolyte composition significantly enhances the lithium secondary battery's performance by improving ion mobility, capacity retention, and life characteristics at extreme temperatures, providing better resistance and discharge capacity compared to conventional electrolytes.

Implementation Method 1

the electrolyte may function as a medium for the movement of lithium ions between the cathode and the anode

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

a non-aqueous organic solvent comprising a propionate solvent; and a lithium salt. The propionate solvent may comprise at least one of ethyl propionate and propyl propionate

Methodology Applied
Scientific EffectViscosity reduction:

Implementation Method 3

The lithium salt may comprise lithium hexafluorophosphate and lithium bisfluorosulfonylimide

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentUS20240322241A1Electrolyte Solution for Lithium Secondary Battery and Lithium Secondary Battery Comprising the same
Publication Date: 2024.09.26 SK ON CO LTD

AI summary

An electrolyte for a lithium secondary battery according to an embodiment of the present disclosure includes, a non-aqueous organic solvent including a propionate solvent; and a lithium salt. The propionate solvent includes at least one of ethyl propionate (EP) and propyl propionate (PP). The lithium salt includes lithium hexafluorophosphate (LiPF6) and lithium bisfluorosulfonylimide (LiFSI).