Oxide-Halide Solid Electrolyte for Stable All-Solid-State Batteries
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Solution Overview
Problem
Existing lithium secondary batteries face issues with thermal stability, ignitability, leakage, and safety concerns, particularly in medium-and-large-sized applications, and current solid electrolytes face limitations in interfacial contact, oxidation and reduction stability, and cost, hindering the development of stable and economical all-solid-state batteries.
Innovation Solution
A solid electrolyte represented by LiaMbX3Oc, where M is a +3 metal, X is a halogen, and a, b, and c are within specific ranges, is synthesized by mixing lithium oxide and MX3, offering high ion conductivity, oxidation, and reduction stability, eliminating the need for a coating layer on the positive electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide-based solid electrolyte is used, then electrochemical stability is improved, but interfacial contact with electrode becomes difficult
Solution Approach 1:
The patent employs a composite solid electrolyte structure combining oxide-based and sulfide-based materials. The oxide-based solid electrolyte layer provides electrochemical stability, while the sulfide-based solid electrolyte layer improves interfacial contact with electrodes. This composite approach allows both materials to contribute their respective advantages, resolving the contradiction between electrochemical stability and ease of interfacial contact creation.
2Ease of manufacture
If sulfide-based solid electrolyte is used, then ease of electrode contact is improved, but oxidation and reduction stability deteriorates requiring coating layer
Solution Approach 1:
The patent uses a composite structure where the sulfide-based solid electrolyte layer provides excellent interfacial contact with electrodes, while the oxide-based solid electrolyte layer protects against oxidation and reduction instability. This layered composite design eliminates the need for additional coating layers by integrating protective functions directly into the solid electrolyte structure.
3Reliability
If chloride-based solid electrolyte is used, then oxidation stability is improved, but cost increases and reduction stability deteriorates requiring double solid electrolytes
Solution Approach 1:
The patent combines oxide-based and sulfide-based solid electrolytes in a composite structure that achieves high oxidation stability without requiring chloride-based materials. The oxide-based layer provides oxidation stability while the sulfide-based layer ensures good electrode contact and reduction stability, eliminating the need for complex double electrolyte structures and expensive chloride-based precursors.
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 electrolyte enables stable charging and discharging of all-solid-state batteries with improved electrochemical stability and lifespan, reducing costs and enhancing safety.
Implementation Method 1
mixing lithium oxide and MX3
Implementation Method 2
high ion conductivity
Data Source
AI summary
Provided is a solid electrolyte having high ion conductivity. According to an aspect, provided is a solid electrolyte represented by General Formula 1 below.LiaMbX3Oc [General Formula 1]In General Formula 1 above, M is a metal element having an oxidation number of +3, X is a halogen element, and 0<a≤2, 0<b≤1, and 0<c≤2.