Dual-Coated NMC Cathode Material for Low-Cobalt Li-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for large-sized, high-capacity, and high-energy-density rechargeable lithium batteries poses a challenge due to the limited supply and high cost of cobalt, a rare metal used in traditional positive electrode active materials.
Innovation Solution
A positive electrode active material is developed, comprising core particles of lithium nickel-manganese-based composite oxide with a first coating layer containing aluminum and a second coating layer containing cobalt, enhancing capacity, cycle-life, and high-voltage/high-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional cobalt-based positive electrode active materials are used, then high capacity and good cycle-life characteristics are achieved, but production cost increases and cobalt supply becomes limited
Solution Approach 1:
The patent extracts cobalt from the positive electrode active material composition, developing a cobalt-free lithium nickel-manganese-based composite oxide. This eliminates dependence on scarce and expensive cobalt while maintaining battery performance through optimized nickel-manganese ratios and dual coating layers
Solution Approach 2:
The patent creates a composite material system consisting of lithium nickel-manganese-based composite oxide core particles with dual coating layers (aluminum oxide and lithium nickel oxide). This composite structure replaces traditional cobalt-based materials while achieving comparable or superior capacity and cycle-life characteristics
2Ease of manufacture
If cobalt-free positive electrode active materials are developed, then production cost is reduced, but capacity and cycle-life characteristics may deteriorate
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core contains lithium nickel-manganese-based composite oxide optimized for capacity, while the shell contains dual coating layers (aluminum oxide and lithium nickel oxide) optimized for stability and cycle-life. Each region has tailored composition to fulfill specific functional requirements
Solution Approach 2:
The patent changes key parameters including nickel content (40-80 mol%), manganese content (20-60 mol%), and introduces dual coating layers with controlled thickness (1-20 nm). These parameter optimizations enable cobalt-free materials to achieve capacity ≥180 mAh/g and maintain ≥80% capacity retention after 500 cycles
3Use of energy by moving object
If high-voltage operating conditions are applied, then energy density is improved, but material stability and cycle-life characteristics deteriorate
Solution Approach 1:
The patent applies beforehand cushioning by pre-coating the lithium nickel-manganese-based composite oxide core particles with aluminum oxide and lithium nickel oxide layers before battery assembly. These coating layers act as protective barriers that prevent direct contact between the high-voltage electrolyte and the reactive core material, cushioning against voltage-induced degradation and maintaining stability at 4.2V or higher operating voltages
4Power
If high-temperature operating conditions are applied, then power output is improved, but gas generation and safety issues increase
Solution Approach 1:
The patent converts the potentially harmful high-temperature reactivity of lithium nickel-manganese-based composite oxide into a benefit by applying aluminum oxide and lithium nickel oxide coating layers. These coatings suppress unwanted side reactions and gas generation at high temperatures, while the optimized core composition maintains high power output capability, effectively transforming thermal instability into thermal stability
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 proposed solution maximizes capacity and reduces production costs while ensuring long cycle-life characteristics and improving high-voltage and high-temperature performance, effectively addressing the cobalt supply issues.
Implementation Method 1
performing a first heat treatment to obtain a lithium nickel-manganese-based composite oxide
Implementation Method 2
adding an Al raw material and the lithium nickel-manganese-based composite oxide to an aqueous solvent, followed by mixing
Implementation Method 3
drying them and performing a second heat treatment
Implementation Method 4
performing a second heat treatment
Data Source
AI summary
Disclosed are a positive electrode active material, a method of preparing the same, and a positive electrode and a rechargeable lithium battery including the same, the positive electrode active material including core particles including a layered lithium nickel-manganese-based composite oxide, a first coating layer on a surface of the core particles and containing Al, and a second coating layer on the first coating layer and containing Co.