Solid-State Battery Anode Composition for Garnet Electrolyte Compatibility
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Solution Overview
Problem
In solid-state batteries, the reactivity between garnet-type solid-state electrolytes and negative electrode active materials leads to a reduction in the utilization factor of the active material, limiting battery performance.
Innovation Solution
Incorporating a negative electrode active material with a specific chemical composition, such as Li4WO5, and a molar ratio of Li to M (where M is W, Mo, Ta, or Zr) greater than 2.0, to suppress reactions with the garnet-type solid-state electrolyte during sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a garnet-type solid-state electrolyte is used in the negative electrode layer, then ionic conductivity and potential window are improved, but reactivity with the negative electrode active material increases, reducing utilization factor
Solution Approach 1:
The patent changes the chemical composition parameters of the negative electrode active material, specifically requiring a molar ratio of Li to M (where M is W, Mo, Ta, or Zr) of more than 2.0. This parameter adjustment reduces the reactivity between the active material and garnet-type solid-state electrolyte during sintering, thereby suppressing the decrease in utilization factor while maintaining high ionic conductivity
Solution Approach 2:
The patent creates a composite negative electrode layer containing both the specific negative electrode active material (with Li/M > 2.0) and garnet-type solid-state electrolyte. This composite structure allows the system to benefit from the high ionic conductivity of the garnet-type electrolyte while the specific composition of the active material suppresses harmful reactions, resolving the contradiction between conductivity and utilization factor
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 approach effectively reduces the reactivity between the solid-state electrolyte and the negative electrode active material, thereby enhancing the utilization factor and maintaining battery performance.
Implementation Method 1
the reactivity between a garnet-type solid-state electrolyte and an electrode active material is very high, and sufficient battery performance cannot be obtained. Specifically, in the solid-state battery, when the garnet-type solid-state electrolyte was contained in a negative electrode layer together with a negative electrode active material, the garnet-type solid-state electrolyte reacted with the negative electrode active material at the time of sintering
Data Source
AI summary
A solid-state battery including a positive electrode layer; a negative electrode layer; and a solid-state electrolyte layer between the positive electrode layer and the negative electrode layer, wherein the negative electrode layer includes: a negative electrode active material containing Li, M, and O, wherein M is one or more elements selected from the group consisting of W, Mo, Ta, and Zr, and a molar ratio (Li/M) of a Li content to a M content is more than 2.0; and a garnet-type solid-state electrolyte.