Spinel Cathode Material Suppressing Manganese Dissolution
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Solution Overview
Problem
Current cathode active materials for rechargeable lithium batteries, such as LiMn2O4 and Li1.1Mn1.9O4, suffer from manganese dissolution at high temperatures, leading to rapid capacity deterioration, which has not been adequately addressed by previous attempts at substitution or surface coating.
Innovation Solution
A spinel type cathode active material is developed by substituting MgAl2O4 and Co3O4 into the basic spinel structure of Li1.1Mn1.9O4, combined with metal oxide nanoparticles to enhance structural stability and electronic conductivity, and to scavenge hydrogen fluoride generated by electrolyte decomposition, thereby suppressing manganese dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If LiMn2O4 or Li1.1Mn1.9O4 is used as cathode active material, then thermal stability and structural stability are improved, but manganese dissolution occurs at high temperature leading to rapid capacity deterioration
Solution Approach 1:
The patent applies composite materials by combining Li1.1Mn1.9O4 spinel structure with surface coating layers and dopant elements. The composite structure integrates the thermally stable spinel core with protective surface modifications, creating a multi-functional material that maintains structural stability while preventing manganese dissolution through the combined effects of the base structure and surface engineering.
Solution Approach 2:
The patent implements local quality by applying surface coating specifically to the outer surface of the Li1.1Mn1.9O4 particles and introducing dopant elements at specific lattice positions. This localized modification approach preserves the bulk structural stability of the spinel while addressing the surface-related manganese dissolution issue, allowing different regions of the material to fulfill different functional requirements.
2Object-affected harmful factors
If substitution or surface coating is applied to LiMn2O4, then manganese dissolution is partially suppressed, but capacity deterioration at high temperature remains significant
Solution Approach 1:
The patent merges multiple protective strategies by combining surface coating with dopant incorporation and optimizing the Li1.1Mn1.9O4 composition. This combination approach integrates the benefits of surface protection, bulk structural stabilization through doping, and compositional optimization, creating a synergistic effect that more effectively suppresses manganese dissolution and maintains high temperature performance than any single method alone.
Solution Approach 2:
The patent creates a composite material system that integrates the Li1.1Mn1.9O4 spinel phase with surface coating layers and dopant elements. This composite structure allows the bulk material to provide thermal stability while the surface and dopant components work together to prevent manganese dissolution, achieving superior high temperature performance through the combined functionality of its constituents.
3Reliability
If Li[(Ni0.5Mn0.5)1-xCox]O2 is used to increase electron conductivity, then capacity and reversibility are improved, but thermal instability in charged state persists
Solution Approach 1:
The patent extracts the problematic Ni component from the cathode material composition and replaces it with Mn-rich Li1.1Mn1.9O4 spinel structure. By removing the thermally unstable Li[(Ni0.5Mn0.5)1-xCox]O2 phase while maintaining good electrochemical reversibility through the spinel structure's inherent properties, the patent eliminates the thermal instability issue while preserving electrochemical performance.
Solution Approach 2:
The patent changes the compositional parameters by transitioning from Li[(Ni0.5Mn0.5)1-xCox]O2 with its specific Ni-Co-Mn ratio to Li1.1Mn1.9O4 with optimized Li excess and Mn content. This parameter change in composition and structure fundamentally alters the thermal stability characteristics while maintaining electrochemical reversibility through the spinel structure's conductivity and ion transport properties.
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 improved structural stability, electronic conductivity, and extended lifespan of rechargeable lithium batteries by reducing manganese dissolution, achieving low price, high output, and long lifespan while maintaining high capacity.
Implementation Method 1
Co3O4 is substituted into the basic spinel structure of Li1.1Mn1.9O4 to improve electronic conductivity
Implementation Method 2
combined with metal oxide nanoparticles to enhance structural stability and electronic conductivity, and to scavenge hydrogen fluoride generated by electrolyte decomposition
Implementation Method 3
spinel type cathode active material which exhibits excellent electrochemical characteristics and thermal stability
Data Source
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AI summary
The present invention relates to an anode active material for rechargeable lithium batteries and a method of manufacturing the same. The method includes preparing an anode active material for rechargeable lithium batteries includes heat treating a mixture of Li2CO3, MnO2, MgO, Al2O3 and Co3O4 at 900 to 1000°C in air or an oxygen atmosphere for 10 to 48 hours to generate a lithium-containing oxide; generating metal oxide nanoparticles MO (5 to 500 nm) (where M represents one of Mg, Co and Ni, and has a valence of 2); and dry or wet mixing 0.01 to 10 wt% of the pulverized metal oxide nanoparticles with the lithium-containing oxide to form an anode active material. According to the present invention, spinel type MgAl2O4 is substituted into a basic spinel structure represented by Li1.1Mn1.9O4 to provide structural stability and spinel type Co3O4 is substituted into the basic spinel structure of Li1.1Mn1.9O4 to improve electronic conductivity, thereby improving battery performance. Further, metal oxide nanoparticles MO (5 to 500 nm) (where M represents one of Mg, Co and Ni, and has a valence of 2) provided as an additive act as scavengers of HF generated by decomposition of the electrolyte, so that the spinel type anode active material may be used as an anode active material of spinel type LiMn2O4 for rechargeable lithium ion batteries, thereby realizing low price, high output, long lifespan and high capacity of the rechargeable lithium batteries.