Lithium Composite Oxide with Sequential ZrO2 and LiZrO2 Coatings
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high capacity, high output, and safety, particularly in high-performance electric vehicles, where existing positive electrode active materials do not adequately address issues of lifespan and storage characteristics at high temperatures.
Innovation Solution
A positive electrode active material is developed, comprising a lithium composite oxide with sequential zirconium oxide and lithium zirconium oxide coating layers, which are formed through a specific preparation method involving mixing, drying, and heat-treating with zirconium and lithium precursors, enhancing the battery's lifespan and storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a lithium composite oxide is used as a positive electrode active material to achieve high capacity and high output, then the battery performance is improved, but the lifespan and storage characteristics at high temperatures deteriorate due to side reactions with the electrolyte
Solution Approach 1:
A zirconium oxide coating layer is introduced as an intermediary between the lithium composite oxide and the electrolyte. This coating layer acts as a protective barrier that prevents direct contact and side reactions between the active material and electrolyte, thereby improving lifespan and storage characteristics while maintaining the high power performance of the lithium composite oxide
Solution Approach 2:
The positive electrode active material is designed as a composite structure consisting of lithium composite oxide particles coated with zirconium oxide. This composite material combines the high capacity and high output properties of lithium composite oxide with the stability and protective properties of zirconium oxide, resolving the contradiction between power performance and reliability
2Reliability
If the thickness of the zirconium oxide coating layer is increased to improve protection against side reactions, then the lifespan is improved, but the initial efficiency and capacity retention deteriorate due to increased resistance to lithium ion diffusion
Solution Approach 1:
The thickness of the zirconium oxide coating layer is precisely controlled within a specific range (1 nm to 20 nm) to optimize the balance between protection and ion diffusion. This parameter optimization ensures that the coating is thick enough to provide protective barriers against side reactions while remaining thin enough to allow efficient lithium ion diffusion, thereby maintaining both lifespan and initial efficiency
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 solution improves the lifespan and storage characteristics of lithium secondary batteries by forming a stable coating layer that prevents side reactions with the electrolyte, thereby enhancing the battery's capacity retention and safety at high temperatures.
Implementation Method 1
heat-treating the resultant having the lithium precursor added thereto to prepare a positive electrode active material
Implementation Method 2
adding a lithium precursor to the resultant of the mixing and drying process, and heat-treating the resultant having the lithium precursor added thereto
Data Source
AI summary
A positive electrode active material includes a lithium composite oxide and a zirconium oxide coating layer and a lithium zirconium oxide coating layer that are in a form of sequential layers on the lithium composite oxide.