Boron-Doped Sulfide Solid Electrolyte for Moisture-Stable Batteries

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Solution Overview

Problem

Sulfide-based solid electrolytes for all-solid-state batteries are difficult to handle in a general atmosphere due to moisture reactivity, leading to safety concerns and ion conductivity deterioration.

Innovation Solution

Incorporating boron (B) into the argyrodite-type solid electrolyte composition, specifically in the range of 10 ppm to 100,000 ppm, to enhance moisture stability without compromising ion conductivity and battery performance, through a manufacturing process involving mixing, pelletizing, and heat treatment under controlled conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If LiCoO2 cathode material is used to achieve high capacity, then battery capacity is improved, but structural stability deteriorates and safety issues arise

Engineering Contradiction:
Improvebattery capacityVSAvoidstructural stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent uses LiCo0.8Ni0.05Mn0.1O2 as a composite cathode material that combines multiple elements to achieve high capacity while maintaining structural stability. The composite structure allows the material to benefit from the high capacity of lithium cobalt oxide while the additional elements provide structural reinforcement and stability during cycling.

Inventive Principle:
Principle #40Composite materials

2Length of stationary object

If conventional solid electrolyte films are used to achieve thin design, then device thickness is reduced, but manufacturing complexity increases due to multiple coating steps

Engineering Contradiction:
Improveelectrolyte film thicknessVSAvoidmanufacturing process complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines multiple coating steps into a single solution application process. The slurry containing all necessary components (solid electrolyte particles, binder, solvent) is applied in one step, eliminating the need for separate coating steps for different layers and significantly simplifying the manufacturing process while still achieving thin film structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical state and composition parameters of the electrolyte material by using a slurry formulation with specific particle size distributions, binder ratios, and solvent compositions. This allows the material to be applied as a fluid that can be easily coated and then dried to form a uniform thin film, transforming the manufacturing approach from complex multi-step coating to simple solution casting.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If LiCoO2 cathode material is used to achieve high capacity, then battery capacity is improved, but safety deteriorates due to oxygen evolution and exothermic decomposition

Engineering Contradiction:
Improvebattery capacityVSAvoidsafety hazards
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the LiCoO2 structure by doping with nickel and manganese elements to create LiCo0.8Ni0.05Mn0.1O2, which maintains high capacity while suppressing oxygen evolution and exothermic decomposition. The composite structure stabilizes the cathode material and reduces safety hazards during battery operation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces an all-solid-state electrolyte as an intermediary layer between the cathode and other battery components. This solid electrolyte acts as a protective barrier that prevents direct contact and potential reactions, thereby improving safety while allowing the high-capacity LiCo0.8Ni0.05Mn0.1O2 cathode to function.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Quantity of substance

If all-solid-state battery structure is used to achieve high energy density, then energy density is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveenergy densityVSAvoidfilm formation precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent optimizes multiple parameters of the slurry formulation including particle size distribution of solid electrolyte particles, binder content, solvent composition, and drying conditions. By carefully controlling these parameters, the patent achieves uniform thin film formation with good coverage and adhesion, meeting the high precision requirements of all-solid-state battery manufacturing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a slurry with controlled particle packing that creates a porous yet uniform structure in the dried film. This porous structure allows for good ion transport while maintaining film integrity and uniform thickness, achieving the required manufacturing precision for high energy density batteries.

Inventive Principle:
Principle #31Porous materials

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 boron-containing electrolyte improves moisture stability, reduces hydrogen sulfide gas generation, and maintains excellent ion conductivity and cycle-life characteristics of the all-solid-state battery.

Implementation Method 1

solid electrolyte which comprises a porous layer formed by a self-organizing assembly of rod-shaped particles

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

a self-organizing assembly of rod-shaped particles

Methodology Applied
Scientific EffectSelf-organizing assembly: Self-Assembly

Data Source

PatentEP4266444B1Solid electrolyte, method for preparing same, and all-solid-state battery comprising same
Publication Date: 2026.05.06 RES INST OF IND SCI & TECH

AI summary

It relates to a solid electrolyte and an all-solid-state battery containing it, which contains a sulfur compound represented by Chemical Formula 1 below and B in an amount of 10 ppm to 100,000 ppm.         [Chemical Formula 1]     Li7-xPS6-xCl1-yBry (In the Chemical Formula 1, 1 < x < 2, and 0 ≤ y < 1)