Nonaqueous Battery Electrolyte for Low-Resistance Storage Retention

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Solution Overview

Problem

Nonaqueous electrolytic solution secondary batteries face challenges in maintaining a low resistance increasing rate and high capacity maintenance rate after storage.

Innovation Solution

The battery incorporates a negative electrode active material with an amorphous carbon coat layer and a sulfur type electrolyte salt in the nonaqueous electrolytic solution, which includes a carbonate type solvent and methyl acetate, to form a suitable coating film on the negative electrode, reducing irreversible lithium loss and enhancing storage characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional nonaqueous electrolytic solution secondary batteries are used, then the battery can operate with basic storage characteristics, but the resistance increasing rate increases and capacity maintenance rate decreases after storage

Engineering Contradiction:

Improvestorage characteristicVSAvoidresistance increasing rate

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolytic solution by introducing a specific sulfur compound (containing S-S bond) at 0.1-5 mass% and adjusting the solvent mixture ratios. This parameter change transforms the SEI film properties on the negative electrode, reducing resistance increase during storage while maintaining capacity. The specific concentration range and compound selection optimize the balance between storage stability and electrochemical performance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolytic system by combining the sulfur compound with specific carbonate solvents (EC, PC, DMF, DMSO) and lithium salts. This composite approach forms a modified SEI film that integrates protective properties from the sulfur compound with the ionic conductivity of the carbonate solvents, achieving both low resistance increase and high capacity maintenance during storage.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional nonaqueous electrolytic solution secondary batteries are used, then the battery can operate with basic storage characteristics, but the capacity maintenance rate decreases after storage

Engineering Contradiction:

Improvestorage characteristicVSAvoidcapacity maintenance rate

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sulfur compound initially appears as an additive but actually forms a protective SEI film that prevents harmful reactions between the electrolyte and negative electrode during storage. This converted benefit reduces capacity fade and lithium loss, transforming what could be a minor component into a protective mechanism that preserves battery capacity over time.

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

This configuration effectively suppresses the resistance increase and maintains a high capacity retention rate after storage, thereby enhancing the overall storage characteristic of the battery.

Implementation Method 1

a sulfur(S) element is taken as a SOx form in a coating film formed on the negative electrode after an activation treatment

Methodology Applied

Scientific EffectElectrochemical reaction: Electrolysis

Implementation Method 2

a strength ratio (D/G) of a peak strength G at 1580 cm−1 and a peak strength D at 1360 cm−1 under a Raman spectrum analysis measured by a Raman spectroscopy

Methodology Applied

Scientific EffectRaman scattering: Scattering

Implementation Method 3

a SOx concentration calculated on a basis of a XPS spectrum measured by a X-ray photoelectron spectroscopy

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS20250140930A1Nonaqueous electrolytic solution secondary battery

Publication Date: 2025.05.01 PRIME PLANET ENERGY & SOLUTIONS INC

AI summary

A secondary battery 100 disclosed herein includes a negative electrode 60 and a nonaqueous electrolytic solution 80. The negative electrode 60 includes a negative electrode active material layer 64 containing a negative electrode active material. The negative electrode active material includes a carbon material and an amorphous carbon coat layer covering the carbon material. The negative electrode active material has a strength ratio (D/G) of a peak strength G at 1580 cm−1 and a peak strength D at 1360 cm−1 under a Raman spectrum analysis is equal to or more than 0.3 and not more than 0.5. The nonaqueous electrolytic solution 80 contains at least a sulfur type electrolyte salt and a nonaqueous solvent, and a nonaqueous solvent contains a carbonate type solvent and methyl acetate. A SOx concentration of the negative electrode active material layer 64 is equal to or more than 0.3 atomic %.