Positive Electrode Material Heat Profile for Stable High-Capacity Batteries
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Solution Overview
Problem
Current lithium-ion secondary batteries face challenges in achieving high charge and discharge capacity, voltage, and stability, with existing positive electrode active materials deteriorating over time, leading to reduced performance and safety concerns.
Innovation Solution
A positive electrode active material is manufactured using a cobalt compound containing nickel, cobalt, and manganese through a coprecipitation method, followed by multiple heat treatments to improve mixing state and crystallinity, and the addition of aluminum as an additive element to enhance stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a positive electrode active material is used in lithium-ion secondary batteries, then high energy density and capacity are achieved, but the material deteriorates over time leading to reduced performance and safety concerns
Solution Approach 1:
The patent applies parameter changes by precisely controlling the atomic ratios of nickel, cobalt, and manganese in the positive electrode active material. Specifically, the nickel content is set to 0.80 or more (on a molar basis normalized to Li), while cobalt and manganese are controlled within specific ranges. This parameter optimization enables the material to achieve high capacity (4.2 mAh/g or more at 45°C) while maintaining stability and safety over extended cycling periods.
Solution Approach 2:
The patent employs composite materials by creating a multi-element system comprising lithium, nickel, cobalt, and manganese in specific proportions. The composite structure LiNixCoyMnzO2 combines the high capacity contribution from nickel with the stability provided by cobalt and manganese, achieving a synergistic effect that simultaneously delivers high energy density and long-term reliability.
2Quantity of substance
If existing positive electrode active materials are used, then high charge and discharge capacity is achieved, but voltage decreases over time
Solution Approach 1:
The patent maintains high charge and discharge voltage (4.35 V or more at 45°C after 500 cycles) while preserving high capacity through precise compositional parameter control. The specific nickel-cobalt-manganese ratio optimization prevents voltage fade by stabilizing the crystal structure during cycling, allowing the material to sustain both high capacity and high voltage simultaneously.
3Productivity
If conventional manufacturing methods are used, then production efficiency is maintained, but manufacturing precision and material uniformity are insufficient
Solution Approach 1:
The patent establishes specific compositional parameters (nickel: 0.80 or more, cobalt: 0.05-0.25, manganese: 0.05-0.20 on molar basis) that serve as precise manufacturing targets. These parameter specifications enable manufacturers to achieve consistent material uniformity across production batches while maintaining efficient manufacturing processes.
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 method results in a positive electrode active material with improved capacity retention, stability, and safety, leading to a highly reliable secondary battery with extended lifespan and enhanced charge and discharge performance.
Implementation Method 1
a first mixture of the cobalt compound and a lithium compound is heated at a first temperature; after the first mixture is ground or crushed, heating is further performed at a second temperature that is higher than the first temperature
Implementation Method 2
Moisture is released by the heating at the first temperature
Implementation Method 3
after the heated mixture is ground or crushed
Implementation Method 4
a cobalt compound (also referred to as a precursor) containing nickel, cobalt, and manganese is obtained by a coprecipitation method
Implementation Method 5
the addition of aluminum as an additive element to enhance stability and performance
Data Source
AI summary
A positive electrode active material with high charge and discharge capacity is provided. A novel positive electrode active material is provided. The positive electrode active material is manufactured in such a manner that after a cobalt compound (also referred to as a precursor) containing nickel, cobalt, and manganese is obtained by a coprecipitation method, a mixture obtained by mixing a lithium compound and the cobalt compound is heated at a first temperature; after the mixture is ground or crushed, heating at a second temperature that is a temperature higher than the first temperature is further performed; and after an additive is mixed, third heat treatment is performed. The first temperature is higher than or equal to 400° C. and lower than or equal to 700° C. The second temperature is higher than 700° C. and lower than or equal to 1050° C.