All-Solid Battery Electrode Material Optimizing Conductivity

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Solution Overview

Problem

All-solid state secondary batteries face a trade-off between improving electron conductivity and maintaining ion conductivity, leading to decreased discharge capacity and output characteristics when auxiliary conductive agents are added to the electrode active material layer.

Innovation Solution

A material for the electrode comprising a sulfide-based inorganic solid electrolyte and an auxiliary conductive agent with a specific surface area of 1 to 500 m2/g and an aspect ratio of 1.5 or more, featuring metal atoms from Group XII, XIII, or XIV of the periodic table, is used to enhance both electron and ion conductivity without decreasing ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the amount of auxiliary conductive agent is increased, then electron conductivity improves, but discharge capacity decreases

Engineering Contradiction:

Improveelectron conductivityVSAvoiddischarge capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the amount of auxiliary conductive agent within specific ranges (0.1-10 wt% of total electrode material, 0.01-5 wt% of active material) and controls particle parameters (specific surface area and aspect ratio). This enables achieving sufficient electron conductivity with minimal amounts of auxiliary conductive agent, thereby preventing excessive displacement of active material and maintaining high discharge capacity.

Inventive Principle:

Principle #35Parameter changes

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 allows for improved discharge capacity and output characteristics in all-solid state secondary batteries by ensuring sufficient electron conductivity while maintaining ion conductivity, as demonstrated by the use of the electrode material in the battery structure.

Implementation Method 1

The continuous contact between the auxiliary conductive agent and an electrode active material improves the electron conductivity of the electrode active material layer

Methodology Applied

Scientific EffectElectron conductivity: Conduction (electrical)

Implementation Method 2

a sulfide-based inorganic solid electrolyte having conductivity for ions of metal elements belonging to Group I or II of the periodic table

Methodology Applied

Scientific EffectIon conductivity: Fast Ion Conductor

Data Source

PatentUS10693190B2Material for electrode, electrode sheet for all-solid state secondary battery, all-solid state secondary battery, and methods for manufacturing electrode sheet for all-solid state secondary battery and all-solid state secondary battery

Publication Date: 2020.06.23 FUJIFILM CORP

AI summary

Provided are a material for an electrode including an active material, a sulfide-based inorganic solid electrolyte having conductivity for ions of metal elements belonging to Group I or II of the periodic table, and an auxiliary conductive agent having at least one metal atom belonging to Group XII, XIII, or XIV of the periodic table, in which a specific surface area of the auxiliary conductive agent is 1 to 500 m2/g, and a ratio between a major axis length and a minor axis length of a particle constituting the auxiliary conductive agent is 1.5 or more, an electrode sheet for an all-solid state secondary battery and an all-solid state secondary battery in which the material for an electrode is used, and methods for manufacturing an electrode sheet for an all-solid state secondary battery and an all-solid state secondary battery.