Functionalized Crown Ether Electrolytes for Stable High-Voltage Cathodes

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Solution Overview

Problem

Current Li-ion batteries face challenges with cathode stability at high voltages and temperatures, leading to increased resistance and capacity loss due to electrochemical oxidation and structural breakdown, particularly in high nickel content cathodes, which existing electrolytes are not adequately addressing.

Innovation Solution

Incorporation of functionalized crown ethers with oxygen-phosphorus or oxygen-sulfur bonds into the electrolyte, along with aprotic organic solvents and metal salts, to form a stable cathode electrolyte interface (CEI) that suppresses oxidative decomposition and enhances high-temperature performance without passivating the cathode excessively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high voltage cathode materials are used to increase energy density, then battery capacity and energy density are improved, but cathode stability deteriorates due to increased oxidation and structural breakdown

Engineering Contradiction:

Improveenergy densityVSAvoidcathode stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces functionalized crown ether molecules as intermediary compounds that mediate between the high voltage cathode and the electrolyte. These molecules coordinate with metal ions at the cathode surface through their oxygen-phosphorus or oxygen-sulfur bonds, forming a protective interface layer that prevents direct contact between the cathode and electrolyte, thereby suppressing oxidative decomposition while maintaining high voltage operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite electrolyte formulations combining traditional carbonate-based electrolytes with functionalized crown ether additives. This composite approach leverages the high voltage window of carbonate electrolytes while the crown ether components provide additional stabilization through metal ion coordination, creating a synergistic system that achieves both high energy density and cathode stability

Inventive Principle:

Principle #40Composite materials

2Speed

If traditional carbonate-based electrolytes are used, then lithium ion transport is enabled, but additional functional additives are required to passivate the anode and form stable SEI

Engineering Contradiction:

Improvelithium ion transportVSAvoidelectrolyte composition

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The functionalized crown ether molecules perform multiple functions simultaneously: they coordinate with metal ions at the cathode surface to suppress oxidation, scavenge dissolved manganese ions from the cathode, and contribute to forming stable protective interfaces. This multi-functionality reduces the need for separate additives for each purpose, simplifying the overall electrolyte composition while maintaining effective protection

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Temperature

If high temperature operation occurs, then battery performance is maintained, but SEI and CEI layers break down leading to capacity loss

Engineering Contradiction:

Improveoperating temperatureVSAvoidinterface stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The functionalized crown ether molecules form protective interface layers on the cathode surface before thermal degradation can occur. These pre-formed protective layers act as a buffer that remains stable at elevated temperatures, preventing direct thermal degradation of the cathode material and reducing the severity of high-temperature reactions during cycling

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If crown ethers are used as additives, then lithium solvation is improved and charge transfer resistance is decreased, but excessive passivation of the cathode may occur

Engineering Contradiction:

Improvecharge transfer efficiencyVSAvoidcathode passivation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The functionalized crown ether molecules exhibit localized functionality where the oxygen-phosphorus or oxygen-sulfur bonds specifically coordinate with metal ions at the cathode surface interface, while the rest of the molecule remains in the electrolyte bulk. This localized coordination provides charge transfer benefits at the interface without causing excessive bulk passivation, maintaining cathode reactivity

Inventive Principle:

Principle #3Local quality

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 functionalized crown ethers improve the stability and cycle life of high-voltage, high-energy cathodes by sequestrating metal ions and maintaining electrolyte stability, reducing interfacial resistance and capacity loss, while maintaining performance at room temperature.

Implementation Method 1

functionalized crown ethers with oxygen-phosphorus or oxygen-sulfur bonds into the electrolyte, along with aprotic organic solvents and metal salts, to form a stable cathode electrolyte interface (CEI) that suppresses oxidative decomposition

Methodology Applied

Scientific EffectCoordination:

Implementation Method 2

Methodology Applied

Scientific EffectSequestration:

Data Source

PatentUS20240039047A1Functionalized crown ethers for lithium-ion batteries

Publication Date: 2024.02.01 SIONIC ENERGY INC

AI summary

An electrolyte containing functionalized crown ethers suitable for use in electrochemical energy storage devices useful for reducing battery resistance, increasing cycle life, and improving high-temperature performance is disclosed.