Phosphorus-Free Argyrodite Electrolyte to Prevent Battery Short Circuits

Solution Overview

Problem

Existing solid-state batteries using phosphorus-free sulfide electrolytes with iodine and (semi-)metals like Si, Ge, or Sn suffer from rapid short circuits and low power/energy density, despite improved resistance to atmospheric oxygen.

Innovation Solution

A solid electrolyte composition of Li₆+xM₁-yS₅-zR, where M is tungsten, R is iodine, and x, y, z are adjusted to enhance ionic conductivity and stability, with a cubic argyrodite structure, and optionally superhalogenation to lower activation energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phosphorus-free sulfide solid electrolyte with iodine and (semi-)metals like Si, Ge, or Sn is used, then resistance to atmospheric oxygen is improved, but rapid short circuits and low power/energy density occur

Engineering Contradiction:

Improveresistance to atmospheric oxygenVSAvoidpower density

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent applies parameter changes by systematically varying the stoichiometric ratios of elements in the solid electrolyte composition (Li6+xMxSb1-yS5-zR1) and controlling synthesis parameters such as heating temperature (400-600°C) and time (1-7 days) to achieve optimal performance that prevents short circuits while maintaining high power density

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple elements (Li, Sb, M, S, R) in specific ratios to create a multi-component solid electrolyte system where M represents (semi-)metals and R represents halogens, achieving synergistic effects that simultaneously improve oxygen resistance and power density

Inventive Principle:

Principle #40Composite materials

2Reliability

If phosphorus-free sulfide solid electrolyte with iodine and (semi-)metals like Si, Ge, or Sn is used, then resistance to atmospheric oxygen is improved, but short circuits occur

Engineering Contradiction:

Improveresistance to atmospheric oxygenVSAvoidshort circuits

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by systematically varying the stoichiometric ratios of elements in the solid electrolyte composition (Li6+xMxSb1-yS5-zR1) and controlling synthesis parameters such as heating temperature (400-600°C) and time (1-7 days) to achieve optimal performance that prevents short circuits while maintaining high power density

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs inert atmosphere by conducting the synthesis process in an argon atmosphere, which prevents unwanted oxidation and chemical reactions during heating, thereby ensuring the stability and preventing short circuits in the final product

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Reliability

If phosphorus-free sulfide solid electrolyte with iodine and (semi-)metals like Si, Ge, or Sn is used, then resistance to atmospheric oxygen is improved, but low energy density occurs

Engineering Contradiction:

Improveresistance to atmospheric oxygenVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by systematically varying the stoichiometric ratios of elements in the solid electrolyte composition (Li6+xMxSb1-yS5-zR1) and controlling synthesis parameters such as heating temperature (400-600°C) and time (1-7 days) to achieve optimal performance that prevents short circuits while maintaining high power density

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 new electrolyte achieves high performance, high power density, and safety by preventing short circuits and toxic gas formation, with ionic conductivity improved under ambient conditions.

Implementation Method 1

The core of the solid electrolyte according to the invention is a composition with the basic molecular formula: Li 6+x M x Sb 1-y S 5-z R... exhibits enhanced chemical and electrochemical properties... high ionic conductivity

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4479348B1Sulfidic solid electrolyte for solid-state batteries and production method

Publication Date: 2025.11.05 MERCEDES BENZ GROUP AG

AI summary

The invention relates to a solid electrolyte for solid-state batteries, which is designed as a phosphorus-free solid electrolyte with a cubic argyrodite structure. The solid electrolyte is characterised by a composition according to the empirical formula: Li6+x Mx Sb1-y S5-z R for x = 0 to 0.7; y = 0 to 0.7 and z = 0 to 0.7, wherein the (semi)metal M = Si, Sn, W and the halogen R = I1, Cl1 Brz, Br1, and in the event that R = I1 , M = W and x > 0. The invention also relates to a production method.