Li2MnO3 Core-Shell Cathode for Lithium Battery
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Solution Overview
Problem
Current lithium rechargeable battery cathode active materials face challenges such as low capacity, difficulty in synthesis, poor reversibility, and limited energy density, which affect the battery's lifespan and performance.
Innovation Solution
A cathode active material is developed with a core compound represented by Chemical Formula 1 (xLi2MnO3—(1-x)LiM1O2) and a coating layer represented by Chemical Formula 2 (yMnOz—(1-y)LiM2O2), optionally including a reduced graphene oxide layer, manufactured through a process involving surface activation and heat treatment, to enhance electrochemical stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If LiNiO2 is used as cathode active material to achieve high discharging capacity, then battery capacity is improved, but synthesis difficulty increases and stability deteriorates
Solution Approach 1:
The patent uses a composite material structure with Li2MnO3 core and LiNi0.8Co0.1Mn0.1O2 coating layer. The core provides high capacity through lithium extraction, while the coating layer facilitates synthesis and improves stability, resolving the contradiction between capacity and ease of manufacture.
Solution Approach 2:
The patent applies different material compositions to different regions: the core uses Li2MnO3 for high lithium content and capacity, while the surface coating uses LiNi0.8Co0.1Mn0.1O2 for synthesis ease and stability. This local differentiation resolves the contradiction between capacity and manufacturability.
2Reliability
If LiCoO2 with particle diameter of 10 μm is used to ensure structural stability, then reliability is improved, but energy density becomes insufficient
Solution Approach 1:
The patent changes the particle size parameter from conventional 10 μm to 1-5 μm, which increases energy density while the coating layer maintains structural stability. This parameter optimization resolves the contradiction between reliability and energy density.
Solution Approach 2:
The composite structure with Li2MnO3 core and LiNi0.8Co0.1Mn0.1O2 coating enables smaller particle sizes (1-5 μm) to maintain stability, achieving high energy density without sacrificing reliability.
3Ease of manufacture
If Mn-based cathode active material is used to achieve easy synthesis and thermal stability, then ease of manufacture and safety are improved, but capacity becomes small
Solution Approach 1:
The patent creates a composite where Li2MnO3 core provides easy synthesis and thermal stability, while LiNi0.8Co0.1Mn0.1O2 coating enhances capacity. This composite approach resolves the contradiction between ease of manufacture and capacity.
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 solution results in a cathode active material with improved initial coulombic efficiency, lifespan, and output characteristics, effectively addressing the limitations of existing materials by providing a structurally and electrochemically stable structure with enhanced electrical conductivity.
Implementation Method 1
activating a surface of the lithium complex oxide by adding the lithium complex oxide to the basic solution
Implementation Method 2
firing the lithium complex oxide with the activated surface
Data Source
AI summary
The present invention relates to a cathode active material for a lithium rechargeable battery, a method of manufacturing the same, and a lithium rechargeable battery including the same, and provides the cathode active material for the lithium rechargeable battery, including a core including a compound represented by the following Chemical Formula 1, and a coating layer positioned on the core and including a compound represented by the following Chemical Formula 2.xLi2MnO3—(1-x)LiM1O2 [Chemical Formula 1]In Chemical Formula 1, 0<x<1 and M1 is a transition metal.yMnOz—(1-y)LiM2O2 [Chemical Formula 2]In Chemical Formula 2, 0<y<1, 1≤z≤4, and M2 is a transition metal.