Solid-State Battery Cathode Composition for High-Temperature Stability
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Solution Overview
Problem
Conventional solid-state batteries experience a significant increase in interface resistance and decrease in discharge capacity when exposed to high-temperature environments, particularly when fully charged.
Innovation Solution
Incorporating a positive electrode layer with a layered rock salt type structure containing magnesium (Mg) or aluminum (Al) and a garnet type oxide without aluminum (Al) to suppress interface resistance and discharge capacity deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional positive electrode layer containing LCO and garnet type oxide is used, then the battery can operate at high temperature, but interface resistance increases remarkably and discharge capacity decreases in high-temperature environments
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode active material by incorporating specific elements (Ni, Co, Mn, Fe) in controlled ratios, and adjusting the lithium content (0.8 ≤ x ≤ 1.2). These parameter changes optimize the material's stability at high temperatures while preventing interface resistance increase, resolving the contradiction between high-temperature operation and interface resistance stability.
Solution Approach 2:
The patent creates a composite positive electrode active material by combining multiple metal oxides (Ni, Co, Mn, Fe) with lithium oxide in a specific layered rock salt structure. This composite material approach allows the positive electrode layer to maintain both high-temperature operation capability and stable interface resistance, as the synergistic combination of elements provides both thermal stability and electrochemical performance.
2Temperature
If a conventional positive electrode layer containing LCO and garnet type oxide is used, then the battery can operate at high temperature, but discharge capacity decreases remarkably in high-temperature environments
Solution Approach 1:
The patent optimizes the discharge capacity by adjusting the compositional parameters of the positive electrode active material, specifically the ratios of Ni, Co, Mn, and Fe elements, and the lithium content (0.8 ≤ x ≤ 1.2). These parameter changes enable the material to maintain high discharge capacity even at elevated temperatures by improving lithium ion diffusion and electron transport properties.
Solution Approach 2:
The composite positive electrode active material with layered rock salt structure, formed by combining multiple metal oxides with specific ratios, provides enhanced discharge capacity at high temperatures. The synergistic effect of different elements in the composite structure facilitates better lithium ion insertion/extraction and maintains structural stability, thereby preserving discharge capacity under thermal stress.
Data Source
AI summary
A solid-state battery that includes: a positive electrode layer; a negative electrode layer; and a solid electrolyte layer between the positive electrode layer and the negative electrode layer, in which the positive electrode layer includes a positive electrode active material having a layered rock salt type structure and an oxide having a garnet type structure, the positive electrode active material contains at least one of Mg or Al, and the oxide having the garnet type structure does not contain Al.