Nitrile Electrolyte Additives for Stable Li-Rich Cathode Interphases

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Solution Overview

Problem

Batteries that cycle lithium ions face challenges in forming stable protective interphase layers on positive electrode materials, particularly when using layered lithium- and manganese-rich oxides, which can lead to reduced cycling stability and capacity retention.

Innovation Solution

Incorporating a nitrile additive, such as acrylonitrile or adiponitrile, into the electrolyte, which decomposes during cycling to form protective interphase layers on the positive electrode surfaces, isolating the electroactive material from physical contact with the electrolyte.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used with layered lithium- and manganese-rich oxides, then the battery can operate, but the protective interphase layer is unstable leading to reduced cycling stability and capacity retention

Engineering Contradiction:

Improvecycling stabilityVSAvoidinterphase layer stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The nitrile additive acts as an intermediary substance that mediates between the electrolyte and the positive electrode surface. It preferentially reacts with the electrode surface to form a stable interphase layer, preventing direct contact between the unstable conventional electrolyte components and the electrode, thereby resolving the instability issue while maintaining battery operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical composition parameter of the electrolyte by introducing nitrile additives (0.01-10% by weight). This parameter change transforms the interphase layer formation mechanism, enabling stable layer formation on lithium- and manganese-rich oxide surfaces that conventional electrolytes cannot achieve

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional electrolytes are used with layered lithium- and manganese-rich oxides, then the battery can operate, but undesirable chemical reactions occur between electrodes and electrolyte

Engineering Contradiction:

Improvecapacity retentionVSAvoidundesirable chemical reactions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The nitrile additive performs preliminary anti-action by reacting with the electrode surface first to form a protective interphase layer. This preliminary reaction prevents subsequent undesirable chemical reactions between the conventional electrolyte components and the electrode, thereby preserving capacity retention

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The nitrile additive converts the potentially harmful interaction between conventional electrolytes and lithium- and manganese-rich oxides into a beneficial outcome. By sacrificing itself to form the interphase layer, it transforms what would be a harmful degradation reaction into a protective mechanism that enhances capacity retention

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 formation of protective interphase layers by the nitrile additive enhances the cycling stability and capacity retention of lithium-ion batteries by preventing undesirable chemical reactions between the electrodes and the electrolyte.

Implementation Method 1

the nitrile additive may decompose and forms an interphase layer on surfaces of the electroactive material of the positive electrode that isolates the electroactive material from physical contact with the electrolyte

Methodology Applied

Scientific EffectElectrochemical decomposition: Electrolysis

Data Source

PatentUS20250038256A1Nitrile additives for electrolytes of batteries including lithium- and manganese-rich positive electrodes

Publication Date: 2025.01.30 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 nitrile additive.