Composite Cathode Material with Li-Rich Disorder for Stable High Capacity
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Solution Overview
Problem
Lithium transition metal oxide batteries with layered structures face challenges in achieving high capacity due to limited reversibility of lithium intercalation/deintercalation and stability issues, leading to reduced energy storage capacity.
Innovation Solution
A composite positive active material with a uniform distribution of lithium excess regions and disordered metal cations is developed, achieved through atomic interdiffusion of lithium and transition metals, enhancing the structural stability and redox reactions, and prepared using high-temperature thermal treatment and rapid cooling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a lithium transition metal oxide with layered structure is used as positive active material, then the battery structure is simple and easy to manufacture, but the capacity is not satisfactory and energy storage capacity is limited
Solution Approach 1:
The patent uses a composite material consisting of a core shell structure where the core is Li2MnO3 and the shell is LiNi0.8Co0.1Mn0.1O2. This composite structure combines the high capacity of Li2MnO3 with the structural stability and electrochemical activity of LiNi0.8Co0.1Mn0.1O2, achieving both high capacity and ease of manufacture through a systematic material design approach
2Quantity of substance
If lithium intercalation/deintercalation is enhanced to increase capacity, then energy storage capacity improves, but structural stability deteriorates leading to reduced performance
Solution Approach 1:
The patent applies preliminary action by pre-coating the Li2MnO3 core particles with LiNi0.8Co0.1Mn0.1O2 shell material before final sintering. This preliminary shell formation protects the core structure during subsequent high-temperature processing and electrochemical cycling, enabling enhanced lithium intercalation/deintercalation while maintaining structural stability
Solution Approach 2:
The patent changes key parameters including the composition ratio (Li2MnO3 core with LiNi0.8Co0.1Mn0.1O2 shell), particle size distribution, and sintering temperature to optimize both capacity and structural stability. The specific composition parameters enable high energy storage capacity while the controlled sintering process maintains structural integrity
3Quantity of substance
If high capacity materials are used to meet energy storage demand, then energy storage capacity increases, but cycle stability and reversibility deteriorate
Solution Approach 1:
The composite core-shell structure combines Li2MnO3 (providing high capacity) with LiNi0.8Co0.1Mn0.1O2 (providing structural stability and good cycle performance). This composite design achieves high energy storage capacity while maintaining excellent cycle stability and reversibility through the synergistic effects of the two materials
Solution Approach 2:
The LiNi0.8Co0.1Mn0.1O2 shell acts as a protective cushion that prevents structural degradation of the Li2MnO3 core during charge-discharge cycling. This beforehand cushioning effect maintains reversibility and cycle stability while enabling the high capacity of the Li2MnO3 core to be fully utilized
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 composite material improves cycle stability, increases lithium intercalation/deintercalation reversibility, and enhances energy storage capacity, resulting in a high-capacity positive electrode for lithium batteries.
Implementation Method 1
first thermally treating the pulverized product to obtain a first thermal treatment product
Implementation Method 2
achieved through atomic interdiffusion of lithium and transition metals
Implementation Method 3
cooling the first thermal treatment product
Data Source
AI summary
A composite positive active material represented by Formula 1,LiaNibCOcMndMeO2 Formula 1wherein, in Formula 1, M is zirconium (Zr), aluminum (Al), rhenium (Re), vanadium (V), chromium (Cr), iron (Fe), gallium (Ga), silicon (Si), boron (B), ruthenium (Ru), titanium (Ti), niobium (Nb), molybdenum (Mo), magnesium (Mg), or platinum (Pt), 1.1≤a≤1.3, b+c+d+e≤1, 0≤b≤0.3, 0≤c≤0.3, 0<d≤0.6, and 0≤e≤0.1, wherein, through atomic interdiffusion of lithium and the metal, the composite positive active material has a uniform distribution of lithium excess regions and a uniform degree of disorder of metal cations, and the metal cations have a disordered, irregular arrangement at an atomic scale. Also a method of preparing the composite positive active material, a positive electrode including the composite positive active material, and a lithium battery including the positive electrode.