Nonaqueous Battery Electrolyte With Self-Repairing Phosphate Coating

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Solution Overview

Problem

Conventional batteries face issues with electrolyte decomposition leading to increased internal resistance and deteriorated cycle characteristics.

Innovation Solution

A nonaqueous electrolyte solution containing a phosphorus-containing compound insoluble in the solvent, such as Li3PO4, forms a coating film on the positive electrode surface, suppressing oxidative decomposition and allowing the compound to repair the film over time, enhancing cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used in batteries, then the battery can operate, but the electrolyte decomposes leading to increased internal resistance and deteriorated cycle characteristics

Engineering Contradiction:

Improvecycle characteristicsVSAvoidelectrolyte decomposition

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces phosphorus-containing compound particles as an intermediary substance that mediates between the electrolyte and the positive electrode. These particles form a protective coating film on the electrode surface, preventing direct contact and harmful reactions between the electrolyte and electrode, thereby suppressing electrolyte decomposition while maintaining battery operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The phosphorus-containing compound particles proactively form a protective coating film on the positive electrode surface before significant electrolyte decomposition can occur. This preliminary protective action prevents the harmful decomposition reactions, addressing the problem before it fully develops and maintains stable cycle characteristics

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If a coating film is formed on the positive electrode to suppress solvent decomposition, then cycle characteristics improve, but the coating film may become damaged over time

Engineering Contradiction:

Improvecycle characteristicsVSAvoidcoating film durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The phosphorus-containing compound particles in the electrolyte enable the coating film to self-repair when damaged. When the coating film deteriorates or develops defects during battery cycling, the phosphorus-containing particles continuously replenish and repair the film in situ, allowing the protective layer to maintain its integrity and functionality over extended periods

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The phosphorus-containing compound particles continuously supply material to maintain and repair the coating film throughout battery operation. This continuous protective action ensures the coating film remains intact and functional over time, extending its durability and preventing electrolyte decomposition even after repeated charging and discharging cycles

Inventive Principle:

Principle #20Continuity of useful action

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 solution effectively suppresses solvent oxidative decomposition, leading to improved battery cycle characteristics and safety by reducing solvent volatility and agglomeration of the phosphorus-containing compound.

Implementation Method 1

the particles of the phosphorus-containing compound dispersed in the nonaqueous electrolyte solution form a coating film on the surface of the positive electrode

Methodology Applied

Scientific EffectCoating film formation: Deposition (physical)

Implementation Method 2

oxidative decomposition of the solvent at the interface between the nonaqueous electrolyte solution and the positive electrode can be suppressed

Methodology Applied

Scientific EffectOxidative decomposition suppression: Oxidation

Implementation Method 3

even when the coating film becomes damaged over time and through repeated charging and discharging, the particles of the phosphorus-containing compound dispersed in the nonaqueous electrolyte solution are capable of repairing the coating film

Methodology Applied

Scientific EffectFilm repair: Deposition (physical)

Implementation Method 4

improved battery cycle characteristics and safety by reducing solvent volatility

Methodology Applied

Scientific EffectVolatility reduction: Evaporation

Data Source

PatentEP4704210A1Nonaqueous electrolytic solution and nonaqueous electrolyte secondary battery

Publication Date: 2026.03.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

Figure 1

AI summary

A nonaqueous electrolyte solution according to the present disclosure includes a nonaqueous solvent, an electrolyte dissolved in the nonaqueous solvent, and particles of a phosphorus-containing compound. The particles of the phosphorus-containing compound are insoluble in the nonaqueous solvent. The phosphorus-containing compound includes at least one selected from the group consisting of Li3PO4, Na3PO4, K3PO4, LiPO3, LiPO3F, metaphosphoric acid, and calcium phosphate. The nonaqueous electrolyte solution according to the present disclosure has fluidity at 25°C. A secondary battery 100 according to the present disclosure includes a positive electrode 5, a negative electrode 6, and the nonaqueous electrolyte solution according to the present disclosure.