Composite Sulfide Electrolyte for Stable Semi-Solid Batteries
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Solution Overview
Problem
Sulfide-based solid electrolytes face issues with ionic conductivity deterioration due to side reactions with liquid electrolytes, high resistance, low lithium ion yield, flammability, and unstable high-voltage oxidation stability in semi-solid rechargeable batteries.
Innovation Solution
A solid-liquid composite electrolyte is developed, incorporating a sulfide-based solid electrolyte with a liquid electrolyte containing a metal salt and organic solvent, where the anion has a radius less than 295 pm, exhibiting high kosmotropicity to suppress side reactions and maintain high ionic conductivity, oxidation stability, and flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid electrolyte is added to sulfide-based solid electrolyte to prepare solid-liquid composite electrolyte, then ionic conductivity is improved, but side reactions occur on the interface between liquid electrolyte and sulfide-based solid electrolyte
Solution Approach 1:
The patent introduces a solid electrolyte interface (SEI) layer as an intermediary between the liquid electrolyte and sulfide-based solid electrolyte. This SEI layer acts as a protective barrier that prevents direct contact and harmful side reactions between the liquid electrolyte and sulfide-based solid electrolyte, while still allowing lithium ion transport to maintain high ionic conductivity.
Solution Approach 2:
The patent creates a composite electrolyte structure combining sulfide-based solid electrolyte particles with liquid electrolyte, forming a solid-liquid composite electrolyte. This composite structure leverages the high ionic conductivity of sulfide-based solid electrolytes while using the liquid electrolyte to fill gaps and enhance ion transport, achieving synergistic effects.
2Reliability
If liquid electrolyte is introduced into sulfide-based solid electrolyte, then ionic conductivity is enhanced, but flame retardancy is lost due to flammability of liquid electrolyte
Solution Approach 1:
The patent converts the harmful flammability of liquid electrolyte into a beneficial protective mechanism by forming a flame-retardant SEI layer on the surface of sulfide-based solid electrolyte particles. This SEI layer acts as a physical barrier that prevents flame propagation, transforming the safety hazard into a protective feature while preserving the ionic conductivity benefits of the liquid electrolyte.
3Reliability
If conventional composite electrolyte is used, then ionic conductivity is maintained, but high-voltage oxidation stability is low resulting in unstable interface with positive electrode
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte system by selecting specific sulfide-based solid electrolyte materials with appropriate electrochemical stability windows and controlling the ratio of solid to liquid electrolyte components. These parameter changes enable the composite electrolyte to maintain stability at high voltages while preserving ionic conductivity.
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 reduces side reactions, maintains high ionic conductivity, ensures oxidation stability and heat resistance, and enhances the reliability and cycle-life characteristics of semi-solid rechargeable batteries.
Implementation Method 1
the liquid electrolyte includes a kosmotropic salt-containing liquid electrolyte
Implementation Method 2
the liquid electrolyte includes a metal salt and an organic solvent
Implementation Method 3
sulfide-based solid electrolytes have recently attracted much attention due to their high ionic conductivity comparable with liquid electrolytes
Implementation Method 4
high ionic conductivity comparable with liquid electrolytes and high transference number (tLi+≈1)
Implementation Method 5
ensuring oxidation stability, heat resistance, and flame retardancy
Implementation Method 6
solving the problems of the solid electrolyte is underway by adding a liquid electrolyte to the sulfide-based solid electrolyte to prepare a solid-liquid composite electrolyte
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, the salt includes a metal cation and an anion with a radius of less than about 295 pm.