Al-P Coated High-Nickel Cathode Material for High-Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The demand for large-sized, high-capacity, or high-energy-density rechargeable lithium batteries has increased, but the supply of cobalt-based positive electrode active materials is limited due to cobalt's high cost and limited reserves, necessitating the development of cobalt-free or low-cobalt positive electrode active materials.
Innovation Solution
A positive electrode active material is developed, comprising core particles of a layered lithium nickel-manganese-based composite oxide with a nickel content of 60 mol% or higher, coated with a layer containing aluminum (Al) and phosphorus (P), which improves the battery's performance at high temperatures and voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cobalt-based positive electrode active materials are used to achieve high energy density, then battery energy density is improved, but production cost increases and material supply becomes limited
Solution Approach 1:
The patent extracts cobalt from the positive electrode active material composition, developing a layered lithium nickel-manganese-based composite oxide that achieves high energy density without cobalt or with minimal cobalt content, thereby reducing production cost and supply constraints
Solution Approach 2:
The patent creates a composite material system combining lithium nickel-manganese oxide with a specific coating layer containing aluminum and phosphorus, achieving both high energy density and cost-effectiveness through the synergistic properties of the composite structure
2Quantity of substance
If high nickel content (≥60 mol%) is used in layered lithium nickel-manganese-based composite oxide to increase capacity, then battery capacity is improved, but material stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a coating layer with specific aluminum and phosphorus content on the surface of the high-nickel core particles, providing stability enhancement exactly where it is needed (at the surface) without compromising the high-capacity bulk composition
Solution Approach 2:
The patent constructs a core-shell composite structure where the high-nickel core provides capacity and the aluminum-phosphorus coating shell provides stability, allowing both high capacity and material stability to coexist
3Use of energy by moving object
If operating voltage is increased to improve energy density, then battery energy density is improved, but high-temperature performance deteriorates
Solution Approach 1:
The patent introduces an aluminum-phosphorus coating layer as an intermediary between the positive electrode active material and the electrolyte, which mediates the interaction at high voltage and temperature conditions, preventing direct harmful reactions and maintaining reliability
4Ease of manufacture
If cobalt content is reduced or eliminated to lower production cost, then production cost is improved, but supply availability worsens
Solution Approach 1:
The patent removes cobalt from the material composition entirely or reduces it to minimal levels, replacing it with abundant and cheaper nickel-manganese-based compounds, thereby improving both cost and supply availability simultaneously
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A positive electrode active material, a method of preparing the same, a positive electrode, and a rechargeable lithium battery including the positive electrode are provided. The positive electrode active material includes core particles and a coating layer on the surface of the core particles. The core particles include a layered lithium nickel-manganese-based composite oxide having a nickel content (e.g., amount) of greater than, or equal to, about 60 mol% based on 100 mol% of a total metal amount excluding lithium. The coating layer includes Al and P.