Argyrodite-Coated Composite Active Material for Lower Interfacial Resistance
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Solution Overview
Problem
Solid-state batteries face higher interfacial resistance due to charge/discharge reactions at contact points between particles, hindering good battery performance compared to batteries using electrolyte solutions.
Innovation Solution
A composite active material with a sulfur-containing compound having an argyrodite-type crystal structure is applied as a surface portion on the active material, enhancing lithium ion conductivity and reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in solid-state batteries, then safety is improved, but interfacial resistance increases due to charge/discharge reactions at contact points between particles
Solution Approach 1:
A surface portion containing a sulfur-containing compound with argyrodite-type crystal structure is introduced as an intermediary layer between the active material and solid electrolyte. This intermediate layer facilitates lithium ion transport across the interface, reducing interfacial resistance while maintaining the safety benefits of solid electrolyte usage.
Solution Approach 2:
The active material is constructed as a composite structure with a surface portion containing a sulfur-containing compound (Li-P-S-Cl-Br system with argyrodite-type crystal structure). This composite design combines the high safety of solid electrolyte with enhanced interfacial lithium ion conductivity through the specialized surface layer.
2Device complexity
If charge/discharge reactions proceed via contact points between particles, then battery structure is simplified, but interfacial resistance increases and battery performance deteriorates
Solution Approach 1:
The surface portion with sulfur-containing compound is applied locally to the active material particles, creating a specialized interface region with enhanced lithium ion conductivity. This local modification improves interfacial performance without fundamentally changing the overall particle-based battery structure.
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 active material improves battery performance by increasing interfacial contact area, smoothing lithium ion transport, and suppressing void formation, leading to reduced reaction resistance and enhanced discharge capacity retention.
Implementation Method 1
the sulfur-containing compound contains a crystalline phase having an argyrodite-type crystal structure... enhancing lithium ion conductivity and reducing internal resistance
Data Source
AI summary
A composite active material has an active material and a surface portion that is disposed on the surface of the active material and that contains a sulfur-containing compound. The sulfur-containing compound contains a crystalline phase having an argyrodite-type crystal structure. It is preferable that the active material contains a lithium (Li) element and an element M, where M is at least one of a nickel (Ni) element, a cobalt (Co) element, a manganese (Mn) element, and an aluminum (Al) element. It is also preferable that the active material has a core particle and a coating portion disposed on the surface of the core particle.