Electrolyte Additives for Li-Rich Cathodes With Stable Cycling

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Solution Overview

Problem

Batteries that cycle lithium ions face challenges in maintaining cycling stability and capacity retention due to undesirable chemical reactions between electrode materials and electrolytes, particularly when using layered lithium- and manganese-rich oxides as positive electrode materials.

Innovation Solution

Incorporating lithium fluoride (LiF) and lithium phosphate (Li3PO4) as functional additives in the electrolyte, which form protective interphase layers on the electrode surfaces, isolating them from physical contact with the electrolyte and preventing detrimental reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If layered lithium- and manganese-rich oxides are used as positive electrode materials to increase capacity, then battery capacity is improved, but cycling stability deteriorates due to undesirable chemical reactions with electrolyte

Engineering Contradiction:

Improvebattery capacityVSAvoidcycling stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A protective interphase layer is introduced as an intermediary between the lithium- and manganese-rich oxide electrode material and the electrolyte. This interphase layer, formed by additives such as lithium fluoride (LiF) and lithium phosphate (Li3PO4) in the electrolyte, physically separates the electrode from the electrolyte, preventing detrimental chemical reactions while allowing the electrode to maintain its high capacity functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If protective interphase layer is formed on electrode surface to prevent chemical reactions, then cycling stability is improved, but ionic conductivity may deteriorate due to barrier effect

Engineering Contradiction:

Improvecycling stabilityVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The protective interphase layer is designed with non-uniform local properties: it provides dense chemical protection at the electrode interface where reaction prevention is critical, while maintaining sufficient ionic conductivity pathways for lithium ion transport. The layer's composition and structure are optimized locally to balance protection and ion transport needs.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The properties of the protective interphase layer are carefully controlled by adjusting electrolyte additive concentrations and composition. By changing parameters such as the type and amount of additives (e.g., LiF, Li3PO4), the interphase layer's thickness, composition, and ionic conductivity are optimized to achieve both protection and acceptable ion transport.

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 interphase layers significantly improve cycling stability and capacity retention by preventing chemical reactions between the electrodes and electrolyte, enhancing the overall performance of lithium-ion batteries.

Implementation Method 1

the functional additive may deposit on surfaces of the electroactive material of the positive electrode and form an interphase layer thereon that isolates the electroactive material of the positive electrode from physical contact with the electrolyte

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

form an interphase layer thereon that isolates the electroactive material of the positive electrode from physical contact with the electrolyte

Methodology Applied

Scientific EffectPhysical isolation: Physical Containment

Data Source

PatentUS20250023092A1Electrolyte additives for batteries including lithium- and manganese-rich positive electrodes

Publication Date: 2025.01.16 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A battery that cycles lithium ions includes a positive electrode and an electrolyte infiltrating the positive electrode. The positive electrode includes an electroactive material comprising a lithium-and manganese-rich oxide. The electrolyte includes an organic solvent, an inorganic lithium salt, and a functional additive comprising lithium fluoride (LiF), lithium phosphate (Li3PO4), or a combination thereof.