Composite Electrolyte Film for Sulfide Interface Stability
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Solution Overview
Problem
Sulfide-based solid electrolytes in batteries face issues with ionic conductivity deterioration due to interface resistance with other solid particles, chemical side reactions with liquid electrolytes, low lithium ion yield, flammability, and unstable high-voltage oxidation stability, limiting their application in practical batteries.
Innovation Solution
A solid-liquid composite electrolyte is developed, comprising a sulfide-based solid electrolyte and a liquid electrolyte with a salt and organic solvent, where the anion is OTf− or FSI−, and a concentration of 2.5 m to 20 m, incorporating additives, diluents, or polymers to reduce side reactions and enhance ionic conductivity, oxidation stability, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid electrolyte is added to sulfide-based solid electrolyte to prepare a solid-liquid composite electrolyte, then ionic conductivity is improved, but chemical side reactions occur on the interface between liquid electrolyte and sulfide-based solid electrolyte
Solution Approach 1:
The patent introduces a protective coating layer on the sulfide-based solid electrolyte particles that acts as an intermediary between the liquid electrolyte and solid electrolyte interface. This coating prevents direct contact and chemical side reactions while maintaining ionic conductivity, thus resolving the contradiction between improving ionic conductivity through liquid electrolyte addition and preventing harmful chemical side reactions at the interface.
2Reliability
If conventional liquid electrolyte is used with sulfide-based solid electrolyte, then ionic conductivity is enhanced, but flame retardancy is lost due to the flammability of liquid electrolyte
Solution Approach 1:
The patent creates a composite electrolyte system combining sulfide-based solid electrolyte particles with liquid electrolyte, where the solid electrolyte component provides flame retardancy while the liquid electrolyte enhances ionic conductivity. The composite structure allows the non-flammable solid electrolyte to counterbalance the flammability of the liquid electrolyte, achieving both high ionic conductivity and flame safety simultaneously.
3Object-affected harmful factors
If sulfide-based solid electrolyte is used alone, then flame retardancy and oxidation stability are maintained, but interface resistance with solid particles deteriorates ionic conductivity performance
Solution Approach 1:
The patent merges sulfide-based solid electrolyte with liquid electrolyte to form a composite electrolyte system. The liquid electrolyte component reduces interface resistance between solid particles by providing a conductive medium that fills gaps and improves contact, thereby enhancing overall ionic conductivity while the solid electrolyte component maintains flame retardancy and oxidation stability properties.
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 composite electrolyte maintains high ionic conductivity, oxidation stability, and heat resistance, enabling nearly full utilization of positive electrode capacity and improving battery reliability and cycling performance, while ensuring safety and stability at high voltages.
Implementation Method 1
the liquid electrolyte can form additional ion channels in the pores of the solid electrolyte particles
Implementation Method 2
sulfide-based solid electrolytes have recently attracted much attention due to their high ionic conductivity comparable with liquid electrolytes
Data Source
AI summary
Disclosed are includes a solid-liquid composite electrolyte, and a composite electrolyte film, and a semi-solid rechargeable battery including the same, the solid-liquid composite electrolyte including a sulfide-based solid electrolyte and a liquid electrolyte, wherein the liquid electrolyte includes a salt and an organic solvent, an anion in the salt is OTf−, FSI−, or a combination thereof, and a concentration of the liquid electrolyte is about 2.5 m to about 20 m, wherein the solid-liquid composite electrolyte further comprises at least one of an additive, a diluent, and a polymer.