Nonaqueous Electrolyte Composition for Suppressing Lithium Dendrites

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Solution Overview

Problem

Lithium secondary batteries face challenges with lithium metal deposition in a dendritic state on the negative electrode, leading to deteriorating discharge capacity with charge and discharge cycles, limiting the capacity increase of nonaqueous electrolyte secondary batteries.

Innovation Solution

Incorporating a fluorine-containing cyclic carbonic acid ester and an oxalate complex anion in the nonaqueous electrolyte to stabilize lithium ions and improve the deposition state of lithium metal on a carbon material, forming a thin, flexible, and homogeneous film that suppresses dendrite formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal is deposited on the negative electrode during charging, then the battery capacity increases, but lithium metal deposits in a dendritic state leading to deteriorating discharge capacity with charge and discharge cycles

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A carbon material is introduced as an intermediary substrate between the electrolyte and the lithium metal deposition site. The carbon material provides a stable platform for lithium metal deposition, preventing direct contact between lithium metal and the electrode collector, thereby suppressing dendrite formation and improving cycle characteristics while maintaining high capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The open circuit potential of the negative electrode is precisely controlled to be 70 mV or less relative to lithium metal in a fully charged state. This parameter change optimizes the thermodynamic conditions for lithium metal deposition, promoting uniform deposition on the carbon material surface rather than dendritic growth, thus resolving the contradiction between capacity and cycle stability

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If a carbon material capable of absorbing and releasing lithium ions is used for the negative electrode, then the battery can achieve higher capacity, but it is difficult to deposit lithium metal in a good state on the surface of the carbon material

Engineering Contradiction:

Improvebattery capacityVSAvoidlithium metal deposition quality

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The open circuit potential is controlled to be 70 mV or less relative to lithium metal, creating optimal thermodynamic conditions that promote uniform lithium metal deposition on the carbon material surface. This parameter control ensures high-quality deposition while maintaining the carbon material's lithium ion absorption and release capabilities

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The negative electrode uses a composite structure combining carbon material (for lithium ion absorption and release) with deposited lithium metal (for high capacity). The carbon material's surface properties and the controlled deposition process work together to achieve both high capacity and good deposition quality

Inventive Principle:

Principle #40Composite materials

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 the cycle characteristics of nonaqueous electrolyte secondary batteries by stabilizing lithium metal deposition, resulting in improved charge and discharge efficiency and higher capacity.

Implementation Method 1

the nonaqueous electrolyte contains a solvent, a cation, and an anion; the solvent contains a fluorine-containing cyclic carbonic acid ester; the cation includes lithium ions; and the anion includes an oxalate complex anion

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

a lithium ion conductive nonaqueous electrolyte

Methodology Applied

Scientific EffectLithium ion conduction: Conduction (electrical)

Implementation Method 3

the negative electrode contains a carbon material for absorbing and releasing lithium ions

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

In the lithium secondary battery, lithium metal deposits on the negative electrode during charging, and the lithium metal is dissolved in the nonaqueous electrolyte during discharging

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 5

the lithium metal is dissolved in the nonaqueous electrolyte during discharging

Methodology Applied

Scientific EffectDissolution:

Data Source

PatentUS12431530B2Nonaqueous electrolyte secondary battery

Publication Date: 2025.09.30 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a lithium ion conductive nonaqueous electrolyte, wherein the negative electrode contains graphite, an open circuit potential of the negative electrode in a fully charged state is 70 mV or less relative to lithium metal, the nonaqueous electrolyte contains a solvent, a cation, and an anion, the solvent contains a fluorine-containing cyclic carbonic acid ester, the cation includes lithium ions, and the anion includes an oxalate complex anion.