Partitioned Li-Ion Battery Electrolyte for Higher Initial Capacity

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Solution Overview

Problem

Lithium ion secondary batteries using aqueous electrolytes face challenges in achieving high initial discharge capacity due to side reactions involving water, which reduce performance.

Innovation Solution

Incorporating a partition layer with a non-aqueous solid electrolyte containing a matrix polymer, lithium salt, and hydrophobic ionic liquid between the electrodes, which suppresses water movement and side reactions, thereby enhancing the initial discharge capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an aqueous electrolyte is used to improve safety and ion conductivity, then safety and ion conductivity are improved, but initial discharge capacity deteriorates due to water-related side reactions

Engineering Contradiction:

ImprovesafetyVSAvoidinitial discharge capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The battery system is segmented into two distinct electrolyte zones: an aqueous electrolyte region containing the positive electrode and a non-aqueous electrolyte region containing the negative electrode, separated by a partition layer. This segmentation allows each electrode to operate in its optimal electrolyte environment while preventing harmful interactions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A partition layer acts as an intermediary barrier between the aqueous and non-aqueous electrolyte regions. This partition layer selectively allows lithium ion transport while preventing water from reaching the negative electrode, thus eliminating water-related side reactions without compromising the benefits of aqueous electrolyte at the positive electrode.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If an organic solvent-based electrolyte is used to achieve high energy density, then energy density is improved, but safety deteriorates due to flammability

Engineering Contradiction:

Improveenergy densityVSAvoidsafety

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

Different electrolyte types are applied to different locations within the battery system. The positive electrode region uses aqueous electrolyte for safety, while the negative electrode region uses non-aqueous electrolyte for high energy density and voltage compatibility, optimizing both safety and performance in their respective zones.

Inventive Principle:

Principle #3Local quality

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 improves the initial discharge capacity of lithium ion secondary batteries by minimizing water-related side reactions, leading to better charge-discharge characteristics.

Implementation Method 1

the partition layer contains a non-aqueous solid electrolyte A in which a matrix polymer, a lithium salt, and a hydrophobic ionic liquid are combined

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 2

lithium ion secondary batteries that include a positive electrode, a negative electrode, and an electrolyte liquid and perform charge and discharge by allowing lithium ions to travel between the positive electrode and the negative electrode

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS20250015363A1Lithium ion secondary battery

Publication Date: 2025.01.09 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

This lithium ion secondary battery has a negative electrode, a positive electrode, an aqueous electrolyte containing a lithium salt, and a separation layer arranged between the negative electrode and the positive electrode. The aqueous electrolyte is in contact with the positive electrode, and the separation layer includes a non-aqueous solid electrolyte A in which a matrix polymer, the lithium salt and a hydrophobic ionic liquid are compounded.