Nonaqueous Electrolyte Additive for High-Temperature Capacity Retention

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Solution Overview

Problem

Existing lithium secondary batteries face challenges in maintaining high discharge capacity retention, resistance characteristics, and reducing gas generation during high-temperature cycling and continuous charging, which are critical for on-vehicle applications.

Innovation Solution

Incorporating a specific cyclic sulfonate ester compound into the nonaqueous electrolytic solution, represented by Formula (1), to form a polyvalent salt that enhances the thermal stability of the coating film on the electrodes, limiting side reactions and improving discharge capacity retention and resistance characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the positive electrode operates at higher potentials to increase battery capacity, then the battery capacity increases, but the reactivity of the positive electrode increases and side reactions with the electrolytic solution accelerate, causing capacity reduction and increased decomposition gas

Engineering Contradiction:

Improvebattery capacityVSAvoidcapacity retention and gas generation control

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A cyclic carboxylate ester compound is introduced as an intermediary substance between the positive electrode and the electrolytic solution. This compound forms a protective coating film on the positive electrode surface, acting as a mediator that prevents direct contact and side reactions between the electrode and electrolyte, thereby maintaining capacity retention and reducing gas generation during high-temperature continuous charging

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cyclic carboxylate ester compound performs preliminary protective action by forming a stable coating film on the positive electrode before significant side reactions occur. This pre-formed protective layer prevents the harmful reactivity that would otherwise accelerate capacity degradation and decomposition gas generation during high-temperature operation

Inventive Principle:

Principle #9Preliminary anti-action

2Quantity of substance

If the densities of the active material layers of the electrodes are increased to increase battery capacity, then the battery capacity increases, but it becomes difficult to uniformly use the active materials, resulting in nonuniform reaction and partial lithium precipitation

Engineering Contradiction:

Improvebattery capacityVSAvoiduniformity of active material utilization

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The cyclic carboxylate ester compound serves as an intermediary that facilitates uniform lithium ion insertion and extraction at the positive electrode. The coating film formed by this compound ensures homogeneous distribution of electrochemical reactions across the electrode surface, preventing localized lithium precipitation even when active material density is increased

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the battery is subjected to high-temperature continuous charging to accelerate degradation testing, then degradation is accelerated and capacity retention can be evaluated, but decomposition gas generation increases and safety risks arise

Engineering Contradiction:

Improvedegradation evaluation capabilityVSAvoiddecomposition gas generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The cyclic carboxylate ester compound converts the potentially harmful high-temperature charging conditions into a beneficial scenario. By forming a thermally stable coating film, it enables accelerated degradation testing at high temperatures while actually reducing decomposition gas generation, thus transforming a harmful condition into an opportunity to demonstrate improved safety and stability

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 addition of the cyclic sulfonate ester compound improves discharge capacity retention and reduces gas generation during high-temperature cycling and continuous charging, enhancing the performance and safety of energy devices.

Implementation Method 1

Methodology Applied

Scientific EffectElectrochemical reaction:

Data Source

PatentUS12494506B2Nonaqueous electrolytic solution and energy device including the same

Publication Date: 2025.12.09 MU IONIC SOLUTIONS CORP

AI summary

A nonaqueous electrolytic solution may include a nonaqueous solvent and a compound of formula (1):wherein, R1 to R5 are each independently H or an alkyl group with 1 to 3 carbon atoms and optionally a substituent; R6 is an organic group with 1 to 8 carbon atoms and optionally a heteroatom; X is C, S, or P; when X is C, l=0, m=1, and n=1, when X is S, l=0, m=2, and n=1, and when X is P, l=0, m=1, and n=2 or l=1, m=1, and n=1; k is an integer of 2 to 4; and Y is a direct bond or a linking group with 1 to 8 carbon atoms and optionally a heteroatom, and when Y is a direct bond, the compound has an X-X bond and k=2.