Al-Ni Coated Nickel-Manganese Cathode for Gas-Suppressed High Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for high-capacity, high-energy density rechargeable lithium batteries poses a challenge due to the limited supply and high cost of cobalt, a key component in traditional positive electrode active materials.
Innovation Solution
A positive electrode active material is developed, comprising a core particle with a layered lithium nickel-manganese-based composite oxide, a first coating layer containing aluminum (Al), and a second coating layer containing nickel (Ni), which enhances capacity, efficiency, and cycle-life characteristics while reducing cobalt content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cobalt is used in traditional positive electrode active materials, then high capacity and high energy density are achieved, but the cost increases and supply becomes limited
Solution Approach 1:
The patent changes the chemical composition parameters by completely eliminating cobalt from the positive electrode active material. Instead of using traditional lithium cobalt oxide or nickel-cobalt-manganese composite oxide, the invention uses lithium nickel-manganese composite oxide with specific compositional ratios (0.6 ≤ x ≤ 0.8, 0.1 ≤ y ≤ 0.4 where x+y≤1), achieving high capacity without cobalt dependency
Solution Approach 2:
The patent creates a composite material system consisting of lithium nickel-manganese composite oxide combined with aluminum oxide coating layer. This composite structure integrates the high capacity characteristics of nickel-manganese oxide with the protective and stabilizing properties of aluminum oxide, achieving both high performance and cost-effectiveness
2Quantity of substance
If high voltage and high temperature conditions are applied to maximize capacity, then energy density is improved, but gas generation increases and cycle-life deteriorates
Solution Approach 1:
The patent introduces aluminum oxide as an intermediary coating layer between the lithium nickel-manganese composite oxide and the electrolyte. This coating layer acts as a protective barrier that prevents direct harmful interactions at high voltage and temperature, suppressing gas generation while allowing the battery to operate at optimal energy density levels
Solution Approach 2:
The aluminum oxide coating is applied in advance before battery operation to create a protective cushion that prevents harmful reactions during high-voltage and high-temperature operation. This pre-established protective layer suppresses gas generation and stabilizes the electrode structure before any degradation can occur
3Quantity of substance
If high voltage and high temperature conditions are applied to maximize capacity, then energy density is improved, but cycle-life characteristics worsen
Solution Approach 1:
The aluminum oxide coating serves as a protective intermediary that shields the lithium nickel-manganese composite oxide from electrolyte decomposition and structural degradation during high-voltage cycling. This intermediate layer maintains electrode integrity over extended cycles, enabling long cycle-life at high energy density
Solution Approach 2:
The patent optimizes the compositional parameters of the lithium nickel-manganese composite oxide (specific ratios of Ni and Mn) to enhance structural stability at high voltage. The aluminum oxide coating thickness and composition are also optimized to provide maximum protection while maintaining electrochemical performance, achieving both high energy density and long cycle-life
Data Source
AI summary
A positive electrode active material includes a core particle including a layered lithium nickel-manganese-based composite oxide, a first coating layer provided on the surface of the core particle and including Al, and a second coating layer provided on the first coating layer and including Ni. A method for preparing a positive electrode active material includes: mixing a layered nickel-manganese composite hydroxide and a lithium raw material and performing a first heat treatment to obtain a lithium nickel-manganese-based composite oxide, adding an aluminum (Al) raw material to an aqueous solvent, adding the lithium nickel-manganese composite oxide thereto and mixing them, then adding a nickel (Ni) raw material and mixing them, and drying the mixture and performing a second heat treatment.