Core-Shell Cathode Material for High-Temperature Li-Ion Battery Life
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Solution Overview
Problem
Conventional lithium secondary battery positive electrode active materials face issues such as high cost, limited price competitiveness, poor thermal safety, small capacity, and poor high-temperature characteristics, along with challenges in synthesizing materials like LiNiO2 due to cation mixing, leading to gelation and swelling of batteries.
Innovation Solution
A positive electrode active material comprising a first composite oxide with a second composite oxide forming a solid solution on its surface, creating a core-shell structure that enhances lithium ion conductivity, structural stability, and thermal stability, thereby improving lifespan characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiCoO2 is used as positive electrode active material, then charge/discharge efficiency and lifespan characteristics are improved, but cost increases due to cobalt resource limitation
Solution Approach 1:
The patent changes the chemical composition parameters by replacing cobalt with nickel and manganese in specific ratios (LiNi0.8Co0.1Mn0.1O2), thereby maintaining electrochemical performance while reducing material cost and resource dependency
Solution Approach 2:
The patent creates a composite oxide material LiNi0.8Co0.1Mn0.1O2 that combines the advantages of nickel (high capacity), cobalt (charge/discharge efficiency), and manganese (thermal stability) to achieve reliable performance at lower cost
2Quantity of substance
If LiNiO2-based positive electrode active material is used, then discharge capacity is improved, but synthesis difficulty increases due to cation mixing between Li and transition metal
Solution Approach 1:
The patent optimizes the stoichiometric ratios of elements (Ni: 0.8, Co: 0.1, Mn: 0.1) to suppress cation mixing while maintaining high discharge capacity, making the material synthetically feasible
Solution Approach 2:
The patent develops a composite oxide LiNi0.8Co0.1Mn0.1O2 where cobalt and manganese are introduced to stabilize the crystal structure and prevent cation mixing, enabling successful synthesis of high-capacity material
3Temperature
If lithium manganese oxide is used as positive electrode active material, then thermal safety and cost are improved, but capacity and high-temperature characteristics deteriorate
Solution Approach 1:
The patent adjusts the metal element ratios (increasing nickel content to 0.8) to enhance discharge capacity while incorporating manganese (0.1) to maintain thermal safety characteristics
Solution Approach 2:
The patent creates a composite oxide LiNi0.8Co0.1Mn0.1O2 that integrates nickel's high capacity, cobalt's electrochemical efficiency, and manganese's thermal stability to achieve both high capacity and thermal safety
4Ease of manufacture
If cation mixing occurs between Li and transition metal, then synthesis becomes difficult, but lithium by-product generation increases causing gelation and swelling
Solution Approach 1:
The patent optimizes the cation ratio parameters (Co: 0.1, Mn: 0.1) to minimize cation mixing and reduce lithium by-product formation, improving both synthesis feasibility and reducing harmful effects
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 core-shell structure improves lithium ion conductivity, enhancing the lifespan and high-temperature storage stability of lithium secondary batteries, while reducing the generation of by-products that cause swelling and gas formation.
Implementation Method 1
a second composite oxide present on at least a part of the surface of the first composite oxide and in a state of forming a solid solution with the first composite oxide
Implementation Method 2
when lithium ions are intercalated/deintercalated into/from a positive electrode and a negative electrode
Data Source
AI summary
The present invention relates to a positive electrode active material, and a lithium secondary battery comprising a positive electrode including the positive electrode active material.