Solid-State Battery Anode Composition Against Current Collector Sulfidation
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Solution Overview
Problem
The sulfide solid electrolyte in all solid state batteries reacts with the anode current collector, leading to sulfurization and increased internal resistance, which deteriorates battery properties over time.
Innovation Solution
Incorporating a molten salt with a melting point between 30°C and 80°C into the anode active material layer, which acts as a sacrificial material to protect the anode current collector from sulfidation, thereby suppressing the increase in internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sulfide solid electrolyte is used in the anode active material layer, then high ion conductivity is achieved, but the anode current collector undergoes sulfidation leading to increased internal resistance
Solution Approach 1:
The patent introduces a protective coating layer as an intermediary between the sulfide solid electrolyte and the anode current collector. This coating layer physically separates the two materials, preventing direct contact and thus preventing sulfidation reactions while still allowing ion transport to occur, thereby maintaining high ion conductivity without the harmful sulfidation effect
Solution Approach 2:
The patent employs a sacrificial protective layer that can be easily applied and replaced. This layer serves as a temporary barrier that consumes itself to protect the current collector from sulfidation, and can be replenished during battery maintenance or manufacturing, effectively managing the sulfidation problem through a disposable protective mechanism
2Power
If the anode current collector is made from reactive metals such as Ni, Fe, or Cu, then good electrical conductivity is achieved, but the battery performance deteriorates due to sulfidation reactions
Solution Approach 1:
The patent creates a composite structure by combining the reactive metal current collector with a protective coating material. This composite approach allows the inner metal layer to provide excellent electrical conductivity while the outer protective layer prevents sulfidation reactions, thereby maintaining both high power and long-term reliability
Solution Approach 2:
The protective coating creates an inert environment around the reactive metal current collector, isolating it from the sulfide solid electrolyte. This inert barrier prevents chemical reactions between the metal and sulfur, allowing the current collector to maintain its electrical conductivity without deteriorating battery performance over time
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 molten salt effectively inhibits the corrosion of the anode current collector, maintaining low internal resistance and preserving battery performance even after repeated charge and discharge cycles.
Implementation Method 1
the molten salt acts as a sacrificial material, inhibiting sulfidation and thereby suppressing the increase in internal resistance
Implementation Method 2
the sulfide solid electrolyte reacts with an anode current collector, and the anode current collector may be sulfurized
Data Source
AI summary
A main object of the present disclosure is to provide an all solid state battery in which increase of internal resistance is suppressed. The present disclosure achieves the object by providing an all solid state battery including a cathode, an anode, and a solid electrolyte layer arranged between the cathode and the anode, wherein: the anode includes an anode active material layer and an anode current collector; the anode active material layer contains an anode active material, a sulfide solid electrolyte, and a molten salt of which melting point is 30° C. or more and 80° C. or less; and the anode current collector is a current collector in which a sulfidation due to the sulfide solid electrolyte occurs.