Ionic Liquid Filled Porous Carbon Anode for Battery Stability

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Solution Overview

Problem

Carbon particles used as anode active materials in batteries face challenges in securing ion paths within their pores due to the use of solid electrolytes, which increases resistance and decreases discharge capacity, while filling the spaces between particles with ionic liquid improves ion conductivity but compromises press formability.

Innovation Solution

A method involving immersing carbon particles with pores in an ionic liquid to allow it to flow into the pores and then washing to remove excess liquid from the surface while retaining it inside, ensuring efficient ion conductivity and formability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid electrolyte is used in all-solid-state batteries, then battery safety and stability are improved, but ion paths in pores cannot be secured and resistance increases

Engineering Contradiction:

Improvebattery stabilityVSAvoidresistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using different electrolyte types in different locations: solid electrolyte in the bulk for stability, and ionic liquid specifically in the pore regions for low resistance ion conduction. This spatial differentiation of electrolyte properties resolves the contradiction between overall stability and local ion transport efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The ionic liquid acts as an intermediary substance that mediates between the solid electrolyte and the carbon pore structure. It fills the pores and provides efficient ion conduction pathways while the solid electrolyte maintains the overall battery structure and safety, thus resolving the contradiction through intermediate functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If ionic liquid is filled in the area between anode active material particles, then ion paths are improved, but press formability deteriorates

Engineering Contradiction:

Improveion conductionVSAvoidpress formability

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies local quality by restricting ionic liquid to specific pore regions rather than filling all spaces between particles. This localized placement provides ion conduction benefits in the pores while avoiding excessive ionic liquid that would compromise press formability of the electrode structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses partial action by filling only the necessary pore volumes with ionic liquid rather than completely saturating all inter-particle spaces. This partial filling achieves sufficient ion conduction improvement while maintaining adequate press formability for electrode manufacturing.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If carbon particle pores are filled with ionic liquid, then ion conducting property is improved, but formability deteriorates

Engineering Contradiction:

Improveion conducting propertyVSAvoidformability

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies local quality by differentiating between pore regions (filled with ionic liquid for ion conduction) and inter-particle regions (maintained with solid electrolyte for formability). This spatial differentiation allows carbon particle pores to be optimized for ion conduction while the overall electrode structure maintains manufacturability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses partial action by filling only the pore interiors with ionic liquid while leaving inter-particle spaces with solid electrolyte. This partial filling approach achieves improved ion conducting property through pore saturation without excessive ionic liquid that would degrade electrode formability during manufacturing.

Inventive Principle:

Principle #16Partial or excessive 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

This approach enhances both ion conductivity and formability of anode active material particles, allowing for improved performance in lithium batteries by maintaining discharge capacity and enabling effective press forming.

Implementation Method 1

making the ionic liquid flow into the pores

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

an ionic liquid having a lithium ion conducting property

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS10122019B2Ionic liquid filled porous carbon anode active material and method for manufacturing the same

Publication Date: 2018.11.06 TOYOTA JIDOSHA KK

AI summary

Provided is a method for manufacturing an anode active material particle having good lithium ion conducting property and good formability. The method for manufacturing an anode active material includes a first step of making a carbon particle with pores have contact with an ionic liquid having a lithium ion conducting property, and making the ionic liquid flow into the pores, and a second step of washing the carbon particle after the first step, while leaving the ion liquid inside the pores.