Composite Positive Electrode Material for High-Temperature Battery Stability
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Solution Overview
Problem
Current lithium rechargeable battery materials face challenges in achieving a balance of low cost, high stability, excellent life characteristics, especially at high temperatures, and optimal load characteristics, with existing materials like lithium-manganese-based composite oxides having low capacity and poor high-temperature characteristics, layered lithium-nickel-based oxides being difficult to synthesize and unstable, and layered lithium-cobalt-based oxides being expensive and unstable.
Innovation Solution
A positive electrode active material comprising secondary particles formed by agglomerating primary particles with different crystal structures, such as hexagonal and cubic crystal structures, which include metals like Ni, Co, or Mn, with varying metal concentrations and orientations, enhancing lithium ion movement and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-manganese-based composite oxide with spinel structure is used, then cost is reduced and stability is improved, but capacity and high-temperature characteristics deteriorate
Solution Approach 1:
The patent uses a composite material consisting of layered lithium-nickel-based composite oxide and cubic lithium-manganese-based composite oxide. The layered structure provides high capacity while the cubic structure provides stability, especially at high temperatures. This composite approach resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The patent creates a core-shell structure where the cubic lithium-manganese-based composite oxide forms an outer layer around the layered lithium-nickel-based composite oxide core. This local differentiation allows the core to provide capacity while the shell provides stability and high-temperature resistance, resolving the contradiction between capacity and stability.
2Quantity of substance
If layered lithium-nickel-based composite oxide is used, then capacity and high-temperature characteristics are improved, but synthesis difficulty and stability deteriorate
Solution Approach 1:
The cubic lithium-manganese-based composite oxide acts as an intermediary protective layer around the layered lithium-nickel-based composite oxide. This shell simplifies the synthesis process by providing a stable framework that tolerates the complex layered structure, reducing overall synthesis difficulty while maintaining high capacity.
Solution Approach 2:
By combining layered lithium-nickel-based composite oxide (high capacity) with cubic lithium-manganese-based composite oxide (easy synthesis, stable), the patent creates a composite material that achieves high capacity while maintaining ease of manufacture through the simpler cubic phase.
3Ease of manufacture
If layered lithium-cobalt-based composite oxide is used, then performance balance and ease of synthesis are improved, but cost and stability deteriorate
Solution Approach 1:
The patent replaces expensive cobalt with cheaper manganese in the outer shell layer. The cubic lithium-manganese-based composite oxide provides the necessary stability at low cost, eliminating the need for expensive cobalt while maintaining performance balance and ease of synthesis.
Solution Approach 2:
The patent applies local quality by using cobalt-free manganese-based material for the outer shell that requires stability, while the inner core can use nickel-based material for capacity. This spatial differentiation resolves the contradiction between ease of synthesis and stability without requiring expensive cobalt throughout the entire 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 proposed material improves charge/discharge characteristics, stability, and lifespan of lithium rechargeable batteries, providing a reliable, high-capacity, and cost-effective solution for lithium rechargeable batteries.
Implementation Method 1
A material capable of extracting/inserting lithium ions may be used as a positive electrode active material of materials included in a lithium rechargeable battery
Data Source
AI summary
A lithium metal composite oxide includes a primary particle having a hexagonal crystal structure, and a primary particle having a cubic crystal structure.