Propylene Carbonate Electrolyte Additives for Battery Cycle Life

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium-ion batteries face issues with electrode exfoliation and degradation, particularly when using propylene carbonate-based electrolytes, which limits their cycle life and capacity retention.

Innovation Solution

An electrolyte composition is developed that includes propylene carbonate as a solvent, with specific additives such as vinylene carbonate, lithium difluorophosphate, and prop-1-ene-1,3-sultone, which stabilize the anode and cathode, preventing exfoliation and degradation, and maintaining battery performance over extended cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If propylene carbonate-based electrolyte is used, then battery capacity and power performance are improved, but electrode exfoliation and degradation occur, reducing cycle life

Engineering Contradiction:

Improvebattery power performanceVSAvoidcycle life

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies preliminary action by introducing multiple additives (vinylene carbonate, lithium difluorophosphate, and prop-1-ene-1,3-sultone) that form protective films on the electrodes before degradation can occur. These additives preemptively stabilize the anode solid electrolyte interphase and protect against cathode degradation, preventing the harmful effects of propylene carbonate on electrode structure during extended cycling.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If propylene carbonate is included in the solvent, then electrolyte stability is improved, but electrode degradation is caused, particularly anode exfoliation

Engineering Contradiction:

Improveelectrolyte stabilityVSAvoidanode exfoliation

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent uses additives as intermediary substances that mediate between propylene carbonate and the electrode surfaces. Vinylene carbonate, lithium difluorophosphate, and prop-1-ene-1,3-sultone act as intermediaries by forming stable interface layers that prevent direct harmful interactions between propylene carbonate and the anode, thereby eliminating exfoliation while preserving electrolyte stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies parameter changes by modifying the electrolyte composition through the addition of specific chemical additives. These additives change the interfacial parameters at the electrode-electrolyte boundary, creating stable solid electrolyte interphase layers that prevent anode exfoliation while maintaining the overall stability and performance of the propylene carbonate-based electrolyte system.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If extended cycling is performed, then battery durability is tested, but capacity retention decreases due to electrode degradation

Engineering Contradiction:

Improvebattery durabilityVSAvoidcapacity retention

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies preliminary action by incorporating stability-enhancing additives that form protective films on electrodes before extended cycling begins. These additives preemptively prevent degradation mechanisms, enabling the battery to maintain high capacity retention (>95%) after 800 cycles by stabilizing both anode and cathode structures against degradation during prolonged use.

Inventive Principle:

Principle #10Preliminary action

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 composition significantly extends the cycle life and capacity retention of lithium-ion batteries, with graphite anodes remaining substantially free of exfoliation and maintaining greater than 95% capacity after 800 cycles, enhancing the battery's overall performance and longevity.

Implementation Method 1

a first additive dissolved in the solvent, the first additive being configured to stabilize an anode solid electrolyte interphase

Methodology Applied

Scientific EffectElectrochemical reaction:

Implementation Method 2

a second additive dissolved in the solvent, the second additive being configured to stabilize at least one of an anode, a cathode, or the lithium salt

Methodology Applied

Scientific EffectElectrochemical reaction:

Implementation Method 3

a third additive dissolved in the solvent, the third additive being configured to stabilize at least one of an anode, a cathode, or the lithium salt

Methodology Applied

Scientific EffectElectrochemical reaction:

Implementation Method 4

The electrolyte includes a lithium salt in a solvent and is suitable for conducting lithium ions between the electrodes

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS11646450B2Propylene carbonate-based electrolyte with extended long cycle life

Publication Date: 2023.05.09 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An electrolyte is provided. The electrolyte includes a solvent containing propylene carbonate (PC); a lithium salt dissolved in the solvent; a first additive dissolved in the solvent, the first additive being configured to stabilize an anode solid electrolyte interphase; a second additive dissolved in the solvent, the second additive being configured to stabilize at least one of an anode, a cathode, or the lithium salt; and a third additive dissolved in the solvent, the third additive being configured to stabilize at least one of an anode, a cathode, or the lithium salt. The first, second, and third additives are chemically distinct. Electrochemical cells including the electrolyte are also provided.