Organic Lithium Predoping Material for Battery Energy Density

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Solution Overview

Problem

Conventional alkali metal ion electric storage devices face challenges in increasing energy density while maintaining safety, as existing predoping methods often result in reduced safety due to metallic lithium risks, high costs, or inefficient lithium ion supply.

Innovation Solution

A predoping material represented by Formula (R(̵SM)n) is used, where M is lithium or sodium, and R is an aliphatic hydrocarbon or aromatic hydrocarbon, with a capacity density higher than the positive electrode active material by 50 mAh/g, applied to the positive electrode to enhance energy density and cycle characteristics without additional production processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If metallic lithium foil or vapor deposition of lithium is used to compensate irreversible capacity, then energy density is improved, but safety deteriorates due to fine powder of metallic lithium remaining after predoping

Engineering Contradiction:
Improveenergy densityVSAvoidsafety
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent uses organic lithium compounds (R-OLi) as predoping materials that are consumed during the first charge to form SEI film, replacing dangerous metallic lithium with disposable organic compounds that decompose safely to provide the necessary lithium ions for SEI formation

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical form of lithium from metallic state to organic compound state (R-OLi), fundamentally altering the physical and chemical parameters of the predoping material to eliminate safety hazards while maintaining predoping functionality

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If stabilized metallic lithium is added to negative electrode, then irreversible capacity is compensated, but cost increases and production complexity increases due to additional processes

Engineering Contradiction:
Improveirreversible capacity compensationVSAvoidproduction process simplicity
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent merges the predoping material (R-OLi) directly into the positive electrode active material mixture, combining multiple functions into a single component and eliminating the need for separate predoping processes or additional metallic lithium handling steps

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The organic lithium compound serves multiple functions: it acts as both the positive electrode active material and the predoping agent, providing lithium ions for both energy storage and SEI film formation, thereby simplifying the overall system design

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 predoping material effectively compensates irreversible capacity, maintaining high energy density and safety by forming a lithium ion conductive film, thereby improving charge/discharge efficiency and cycle retention in alkali metal ion electric storage devices.

Implementation Method 1

A part of the lithium ions emitted from the positive electrode on this occasion is irreversibly consumed in the process of forming an SEI film (lithium ion conductive film) by reductive decomposition of the electrolytic solution

Methodology Applied
Scientific EffectReductive decomposition: Reduction

Implementation Method 2

forming an SEI film (lithium ion conductive film)

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP2784845B1Predoping material for electrical lithium or sodium storage device
Publication Date: 2018.07.18 SUBARU CORP
  • EP2784845B1 patent drawingFigure 1A~1C
  • EP2784845B1 patent drawingFigure 2~3
  • EP2784845B1 patent drawingFigure 4

AI summary

There are provided a predoping material, an electric storage device including the material, and a method of producing the device. The predoping material is used for an alkali metal ion electric storage device and is represented by Formula (1):          R(̵SM)n     (I) where M represents lithium or sodium; n represents an integer of 2 to 6; and R represents an aliphatic hydrocarbon, optionally substituted aromatic hydrocarbon, or optionally substituted heterocycle having 1 to 10 carbon atoms.