Secondary Battery Electrolyte With Cyclic Sulfate SEI Protection

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Solution Overview

Problem

Lithium-ion batteries face challenges in achieving higher energy density due to lithium consumption during the formation of a solid electrolyte interface (SEI) film, which reduces coulombic efficiency and cycling performance, especially when using lithium-rich negative electrode materials.

Innovation Solution

Incorporating a lithium-rich metal oxide as a supplement at the positive electrode and adding a cyclic sulfate compound to the electrolyte solution to form protective films on both electrodes, reducing oxygen release and electrolyte oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium-rich metal oxide is added to the positive electrode as a lithium supplement, then energy density is improved, but oxygen is released during delithiation which oxidizes the electrolyte solution and damages the negative electrode

Engineering Contradiction:

Improveenergy densityVSAvoidoxygen release

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

A cyclic sulfate compound is introduced as an intermediary substance in the electrolyte solution. This compound acts as a mediator that reacts with released oxygen to form a protective film on the positive electrode surface, preventing oxygen from oxidizing the electrolyte solution and damaging the negative electrode, thus resolving the harmful effect while maintaining the lithium supplement's energy density benefit

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful oxygen released during delithiation of lithium-rich metal oxide is converted into a beneficial protective film through reaction with the cyclic sulfate compound. The oxygen that would otherwise cause electrolyte oxidation and negative electrode damage is instead utilized to form a stable interface layer that protects the electrode, transforming the harmful byproduct into a protective element

Inventive Principle:

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

2Reliability

If lithium-rich metal oxide is added to the positive electrode, then coulombic efficiency is improved by compensating lithium consumption, but cycling performance deteriorates due to electrolyte oxidation and negative electrode damage

Engineering Contradiction:

Improvecoulombic efficiencyVSAvoidcycling performance

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The cyclic sulfate compound serves as an intermediary that prevents direct contact between released oxygen and the electrolyte solution/negative electrode. By forming a protective film on the positive electrode, it blocks the oxidation pathway while allowing lithium ion transport, thus maintaining high coulombic efficiency without sacrificing cycling performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oxygen byproduct that would normally degrade cycling performance is converted into a protective film component. This transforms the harmful oxidation effect into a beneficial protective layer that stabilizes the electrode interface, enabling both high coulombic efficiency and durable cycling performance

Inventive Principle:

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

3Object-generated harmful factors

If a cyclic sulfate compound is added to the electrolyte solution to form protective films, then oxygen release is reduced and electrolyte oxidation is prevented, but device complexity increases

Engineering Contradiction:

Improveelectrolyte oxidationVSAvoidelectrolyte composition

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The invention modifies the chemical composition parameters of the electrolyte by incorporating a cyclic sulfate compound. This parameter change enables the formation of protective films that reduce oxygen release and prevent electrolyte oxidation, accepting increased compositional complexity as a trade-off for significantly improved battery performance and stability

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

Enhances energy density and improves coulombic efficiency and cycling performance by preventing negative electrode damage and stabilizing the SEI film.

Implementation Method 1

the cyclic sulfate compound forms films at the positive and negative electrodes

Methodology Applied

Scientific EffectElectrochemical reaction:

Implementation Method 2

a cyclic sulfate compound to the electrolyte solution to form protective films on both electrodes

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 3

oxygen anions are activated and participate in reaction (O2−/O−) in the delithiation process. Oxygen on the surface of the lithium supplement at the positive electrode or the lithium-rich positive electrode is released from a lattice position, and some of it will be oxidized into O2 and O2−

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 4

the RH+ will further reduce and consume lithium in a negative electrode

Methodology Applied

Scientific EffectReduction: Reduction

Data Source

PatentUS20260081224A1Secondary battery and electrical apparatus

Publication Date: 2026.03.19 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

AI summary

A secondary battery and an electrical apparatus are disclosed. The secondary battery includes a non-aqueous electrolyte solution containing a cyclic sulfate compound. An electrical apparatus including the secondary battery is also described.