All-Solid Battery Electrode Active Material with Solid Solution Interface

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

All-solid state secondary batteries face degradation in cycle characteristics due to peeling between active material particles, binding agents, and collectors, which affects their long-term performance.

Innovation Solution

An electrode active material comprising a first active material that expands during charging and contracts during discharging, and a second active material that contracts during charging and expands during discharging, with particles forming a solid solution interface, enhancing cycle characteristics, and a solid electrolyte composition including an inorganic solid electrolyte and a binder with specific properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active material particles are used in all-solid state secondary batteries, then ion conductivity and battery performance are improved, but peeling occurs between particles, binding agents, and collectors during charging and discharging cycles, degrading cycle characteristics

Engineering Contradiction:

Improvecycle characteristicsVSAvoidcontact stability between particles

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent introduces a binder as an intermediary substance between active material particles and collectors. This binder maintains stable contact between particles during charging and discharging cycles, preventing peeling while preserving ion conductivity. The binder acts as a mediating layer that accommodates volume changes without compromising the electrical and ionic pathways.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material structures where active material particles are combined with binder materials to form a stable electrode architecture. This composite approach allows the system to benefit from both the high ion conductivity of active materials and the mechanical stability of binders, resolving the contradiction between performance and contact stability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If organic electrolytic solutions are used in lithium ion secondary batteries, then ease of manufacture and ion conductivity are achieved, but liquid leakage and safety issues such as short circuits and ignition occur

Engineering Contradiction:

ImprovesafetyVSAvoidelectrolyte system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by transitioning the electrolyte from liquid to solid state. This fundamental parameter change eliminates the safety issues associated with liquid electrolytes (leakage, ignition) while maintaining ion conductivity through the solid electrolyte material. The solid state changes the physical parameters of the electrolyte system, fundamentally resolving the safety contradiction.

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

The solution significantly improves the cycle characteristics of all-solid state secondary batteries by preventing peeling and maintaining contact between particles, leading to enhanced ion and electron conductivity and extended battery life.

Implementation Method 1

the first electrode active material expands during charging and contracts during discharging, the second electrode active material contracts during charging and expands during discharging

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

an interface in which particles of the first electrode active material and particles of the second electrode active material are in contact with each other forms a solid solution

Methodology Applied

Scientific EffectSolid solution formation: Solid Solution Strengthening

Data Source

PatentUS11050057B2Electrode active material for secondary battery, solid electrolyte composition, electrode sheet for all-solid state secondary battery, all-solid state secondary battery and methods for manufacturing electrode active material for secondary battery, electrode sheet for all-solid state secondary battery, and all-solid state secondary battery

Publication Date: 2021.06.29 FUJIFILM CORP

AI summary

Provided are an electrode active material for a secondary battery containing a first electrode active material and a second electrode active material, in which the first electrode active material expands during charging and contracts during discharging, the second electrode active material contracts during charging and expands during discharging, some of particles constituting the first electrode active material and some of particles constituting the second electrode active material are in contact with each other, and an interface in which the particles constituting the first active material and the particles constituting the second active material are in contact with each other forms a solid solution to form a crystal portion, a solid electrolyte composition, an electrode sheet for an all-solid state secondary battery, and an all-solid state secondary battery for which the electrode active material for a secondary battery is used, and methods for manufacturing the electrode active material for a secondary battery, an electrode sheet for an all-solid state secondary battery, and an all-solid state secondary battery.