Ternary Oxide Cathode Coating for Lower-Resistance Solid-State Batteries
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Solution Overview
Problem
Current cathode active materials for all-solid-state batteries face challenges such as high resistance, poor thermal stability, and limited conductivity, which affect battery performance and safety.
Innovation Solution
A cathode active material is developed with a coating layer containing ternary oxide, specifically lithium (Li), niobium (Nb), and at least one element selected from vanadium (V), zirconium (Zr), or combinations thereof, to reduce battery resistance and enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is formed on the cathode active material surface, then the resistance between the cathode active material and solid electrolyte is reduced and conductivity is improved, but the device complexity and manufacturing process complexity increase
Solution Approach 1:
The coating layer materials (Li, Nb, V, Zr) are pre-mixed with the cathode active material particles before sintering, ensuring uniform distribution and eliminating the need for post-synthesis coating processes. This preliminary action reduces manufacturing complexity while achieving the desired conductivity improvement.
Solution Approach 2:
The coating layer formation is merged with the main sintering process by adding coating materials to the initial mixture. This combines two separate operations (material synthesis and coating) into a single sintering step, reducing process complexity and equipment requirements.
2Quantity of substance
If LiNiO2 is synthesized to achieve high capacity, then the battery capacity is improved, but the thermal stability is poor and commercialization is difficult
Solution Approach 1:
The cathode active material is designed as a composite containing LiNiO2 combined with stabilizing elements (Nb, V, Zr). These additional elements form a composite structure that maintains the high capacity of LiNiO2 while improving thermal stability through the stabilizing influence of the incorporated elements.
Solution Approach 2:
The stabilizing elements (Nb, V, Zr) are incorporated at specific sites within the cathode material structure to provide localized thermal stability enhancement. This allows the bulk material to maintain high capacity characteristics while specific regions provide thermal stability.
3Ease of manufacture
If LiMn2O4 is used to achieve low cost and commercialization, then the price is reduced, but the lifetime is poor due to Jahn-Teller distortion caused by Mn3+
Solution Approach 1:
The oxidation state of manganese is modified by incorporating elements that prevent the formation of Mn3+ ions responsible for Jahn-Teller distortion. This parameter change in the electronic structure eliminates the distortion mechanism while maintaining the low-cost advantage of LiMn2O4-based materials.
Solution Approach 2:
Instead of using expensive materials like LiCoO2, the patent uses cost-effective LiMn2O4-based compositions with added elements to extend lifetime. This approach replaces expensive long-lived materials with cheaper materials that have been modified to achieve adequate lifetime performance.
Data Source
AI summary
A cathode active material for an all-solid-state battery includes: active material particles; and a coating layer covering at least a portion of the surface of the active material particles, wherein the coating layer includes lithium (Li), niobium (Nb), and at least one element selected from the group consisting of vanadium (V), zirconium (Zr) and combinations thereof.