Sodium-Coated Li-Rich Cathode Material for Voltage Decay Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-Manganese-rich materials used in lithium ion batteries are prone to structural transformation during cycling, leading to poor cycle stability and voltage decay, which hinders their commercial application.
Innovation Solution
A Lithium-Manganese-rich material with a substrate coated by a thin layer of sodium-based oxide, specifically formulated with elements like Al, B, and Nb, to enhance stability and performance, and a method involving sintering and coprecipitation to achieve a high tap density and controlled doping for improved electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a layered Lithium-Manganese-rich material is used as cathode material, then high specific capacity (>250 mAh/g) and high safety are achieved, but the material transforms from layered structure to spinel structure during cycling, causing severe voltage decay and reduced energy density
Solution Approach 1:
The patent applies preliminary action by pre-coating the lithium-manganese-rich material surface with aluminum oxide before cycling begins. This protective coating is formed through a controlled thermal treatment process that creates a stable surface layer, preventing the harmful transformation to spinel structure during subsequent electrochemical cycling while maintaining the high capacity layered structure.
Solution Approach 2:
The patent creates a composite material system consisting of the lithium-manganese-rich cathode material combined with an aluminum oxide coating layer. This composite structure combines the high capacity benefits of the layered lithium-manganese-rich material with the structural stability and protective properties of the aluminum oxide coating, preventing Jahn-Teller distortion and spinel transformation during cycling.
2Stability of the object's composition
If the material is coated with a thicker coating layer to improve stability, then structure stability improves, but tap density decreases and manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the coating thickness parameter within the range of 1-10 micrometers, and by adjusting the aluminum content (0.1-1.0 wt%) and sintering temperature (500-900°C) to optimize the balance between structural stability and tap density. This controlled parameter approach ensures the coating is thick enough to provide protection but thin enough to maintain high energy density.
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 provides excellent cycle stability, high discharge specific capacity, and reduced voltage decay, along with improved rate capability and energy density, making the material suitable for industrial production and enhancing battery performance.
Implementation Method 1
a substrate and a coating layer coated on a surface of the substrate; the substrate comprises a substance represented by a chemical formula Li 1.2+x [(Mn a Co b Ni c M 1-a-b-c ) 1-d M' d ] 0.8-x O 2 , the coating layer comprises a substance represented by a chemical formula Na u [Li v (Mn a Co b Ni c M 1-a-b-c ) γ M' 1-v-γ ]O 2
Implementation Method 2
a method for preparing the same
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure relates to the technical field of lithium ion battery, and discloses a Lithium-Manganese-rich material and a preparation method and a use thereof, the material comprises a substrate and a coating layer coated on a surface of the substrate, the substrate comprises a substance represented by a chemical formula Li1.2+x[(MnaCobNicM1-a-b-c)1-dM'd]0.8-xO2, the coating layer comprises a substance represented by a chemical formula Nau[Liν(MnaCobNicM1-a-b-c)γM'1-ν-γ]O2, and the coating layer in the Lithium-Manganese-rich material has a thickness of 10-100nm. The Lithium-Manganese-rich material provided by the present disclosure has high initial coulombic efficiency, excellent cycle stability, high discharge specific capacity and desirable rate capability.