Composite Cathode Conductive Network for Lower Solid-State Battery Resistance

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Solution Overview

Problem

All-solid-state batteries face challenges in balancing electron transfer resistance, ion transfer resistance, and interfacial resistance due to the reduced volume ratio of electron-conducting materials, which can be exacerbated by the high reactivity between carbon-based conductive materials and sulfide-based solid electrolytes, leading to increased internal resistance and deteriorated performance.

Innovation Solution

A composite cathode comprising a predetermined ratio of spherical and linear conductive materials, such as carbon black and carbon nanotubes, forms an effective conductive network while minimizing side reactions with the sulfide-based solid electrolyte, thereby reducing electrical and ionic resistances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon-based conductive material is added to improve electronic conductivity, then electronic conductivity is improved, but internal resistance increases due to side reactions with sulfide-based solid electrolyte

Engineering Contradiction:

Improveelectronic conductivityVSAvoidinternal resistance

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses a composite conductive material comprising metal particles (0.1-5 wt%) dispersed in a carbon-based conductive material matrix (95-99.9 wt%). This composite structure combines the high electronic conductivity of metals with the chemical stability of carbon materials, improving electronic conductivity while minimizing side reactions with the sulfide-based solid electrolyte that would otherwise increase internal resistance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the concentration of metal particles in the conductive material to 0.1-5 wt%, which is a significant reduction compared to conventional carbon-only additives. This parameter change ensures sufficient electronic conductivity while minimizing the harmful side reactions between conductive material and solid electrolyte, thus controlling internal resistance

Inventive Principle:

Principle #35Parameter changes

2Volume of stationary object

If volume ratio of electron-conducting materials is reduced in all-solid-state battery, then space for ion-conducting solid electrolyte is increased, but electron transfer resistance increases

Engineering Contradiction:

Improvesolid electrolyte volumeVSAvoidelectron transfer resistance

Core Design Contradiction:

Volume of stationary objectVSReliability

Solution Approach 1:

The composite conductive material with metal particles dispersed in carbon matrix provides superior electronic conductivity per unit volume compared to conventional carbon-only materials. This allows the patent to reduce the overall volume of conductive materials while maintaining sufficient electron transfer pathways, thereby increasing space for solid electrolyte without significantly increasing electron transfer resistance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The metal particles are strategically distributed within the carbon matrix to create localized high-conductivity pathways. This local quality enhancement ensures that electron transfer resistance remains low even when the overall volume of conductive material is reduced, allowing more space for ion-conducting solid electrolyte

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 composite cathode achieves balanced conductivity improvements, enhancing initial charge/discharge efficiency and output characteristics by optimizing the conductive network and minimizing side reactions.

Implementation Method 1

a composite conductive material that includes both a spherical conductive material and a linear conductive material... improves electronic conductivity

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

improving electronic conductivity and ionic conductivity in a balanced manner... reducing electrical resistance, ionic resistance

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS20250316699A1Composite cathode for all-solid-state battery including two types of conductive materials

Publication Date: 2025.10.09 HYUNDAI MOTOR CO LTD

AI summary

A composite cathode for an all-solid-state battery including two types of conductive materials. Electron transfer resistance, ion transfer resistance, and interfacial resistance of the composite cathode are reduced in a balanced manner using a composite conductive material including a spherical conductive material and a linear conductive material in a predetermined weight ratio. This configuration improves the initial charge/discharge efficiency, reversible capacity, and output characteristics of the all-solid-state battery.