DES Cathode Interlayer for Low-Resistance Solid-State Battery Interfaces
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Solution Overview
Problem
Conventional solid-state lithium metal batteries face high interfacial resistance between the cathode and solid-state electrolyte due to their rigid nature, leading to limited contact area and poor Li-ion accessibility, resulting in low ionic conductivity, high impedance, and reduced current density.
Innovation Solution
The use of a deep-eutectic-solvent-based electrolyte comprising a lithium salt and a sulfone compound is introduced between the cathode and solid-state electrolyte, providing a liquid electrolyte that wetting the interface and offering continuous, uniform ion paths, thereby reducing interfacial resistance and enhancing ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid solid-state electrolyte is used, then safety and stability are improved, but interfacial resistance increases and ionic conductivity decreases
Solution Approach 1:
The patent uses a composite structure combining solid-state electrolyte particles with liquid electrolyte filling the voids between them. This composite approach allows the system to maintain the safety and stability of solid-state electrolytes while incorporating the high ionic conductivity and flexibility of liquid electrolytes, thereby reducing interfacial resistance without sacrificing reliability.
2Object-affected harmful factors
If a liquid electrolyte is used, then ionic conductivity and contact area are improved, but safety concerns increase
Solution Approach 1:
The patent applies local quality by using liquid electrolyte only in the interfacial regions between solid-state electrolyte particles, rather than throughout the entire battery. The liquid electrolyte is confined to the voids and gaps between rigid particles, providing high ionic conductivity where needed while maintaining the overall safety and structural integrity of the solid-state system.
3Reliability
If ceramic solid-state electrolyte is used, then stability against Li metal is improved, but contact area with cathode is limited
Solution Approach 1:
The liquid electrolyte acts as an intermediary between the rigid ceramic solid-state electrolyte particles and the cathode. It fills the gaps and conforms to the surfaces of both the solid particles and cathode, creating extensive contact areas while the solid-state particles maintain their stability against Li metal. The liquid mediator enables good electrical contact without compromising the protective properties of the solid-state material.
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
This configuration significantly reduces interfacial resistance and increases capacity retention, enabling the solid-state battery to withstand more cycles without failure and maintain functionality for a longer period, while also addressing safety concerns associated with liquid electrolytes.
Implementation Method 1
the ability of the liquid electrolyte to conform to the first major surface of the cathode and/or a surface of the solid-state electrolyte
Implementation Method 2
due to the high ionic conductivity of the liquid electrolyte
Data Source
AI summary
Batteries include a cathode, an interlayer disposed on the cathode, a solid-state electrolyte disposed on the interlayer, and a lithium anode disposed on the solid-state electrolyte. The interlayer includes a deep-eutectic-solvent-based electrolyte including a lithium salt and a sulfone compound. Methods of forming a battery comprising disposing a deep-eutectic-solvent-based electrolyte comprising a lithium salt and a sulfone compound on a first major surface of a cathode. Methods further comprising disposing a solid-state electrolyte over the first major surface of the cathode. The deep-eutectic-solvent-based electrolyte is positioned between the cathode and the solid-state electrolyte.