Tungsten-Coated NCM Cathode Particles for High-Voltage Li Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium composite transition metal oxides in the form of single particles exhibit low lithium mobility, leading to degraded battery capacity and output characteristics, and when operated at high voltages above 4.35 V, they suffer from severe side reactions and performance degradation due to transition metal ion dissolution.
Innovation Solution
A positive electrode active material comprising a lithium composite transition metal oxide with a nickel content of 50-80 mol% and a tungsten-containing coating layer, with a lithium-to-tungsten ratio of 30-45, forms a single or pseudo-single particle structure, enhancing lithium mobility and stability at high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium composite transition metal oxide in the form of single particle is used, then particle strength is excellent and side reaction with electrolyte is reduced, but lithium mobility is low and battery capacity is degraded
Solution Approach 1:
The single particle is divided into multiple primary particles (2-50 particles) that aggregate to form the particle structure. This segmentation allows lithium ions to diffuse through multiple interfaces, enhancing lithium mobility while maintaining the overall particle integrity and strength.
2Productivity
If operating voltage is increased to 4.35 V or more to achieve high-capacity battery, then battery capacity is improved, but side reaction with electrolyte solution becomes severe and performance degradation occurs
Solution Approach 1:
The positive electrode active material uses a composite structure combining lithium nickel cobalt manganese oxide (NCM) with lithium nickel cobalt aluminum oxide (NCA). This composite material approach allows the electrode to operate at high voltages (4.35 V or more) while the NCA component provides structural stability, preventing performance degradation and suppressing side reactions with the electrolyte.
3Productivity
If lithium nickel oxide is used to achieve high capacity, then capacity characteristics are improved, but structural stability is poor and life characteristics are degraded
Solution Approach 1:
The patent creates a composite material where lithium nickel cobalt aluminum oxide (NCA) is combined with lithium nickel cobalt manganese oxide (NCM). The NCA component provides excellent structural stability that compensates for the poor structural stability of pure lithium nickel oxide, while maintaining high capacity characteristics. This composite structure enables both high capacity and long cycle life.
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 material improves capacity and maintains stable performance at high voltages by controlling the lithium-to-tungsten ratio, allowing for effective lithium intercalation and deintercalation, thereby enhancing battery efficiency and resistance.
Implementation Method 1
a positive electrode active material including a lithium composite transition metal oxide which has an amount of nickel among total metals excluding lithium of 50 mol% to 80 mol% and is in a form of a single particle composed of one single nodule or a pseudo-single particle that is a composite of 40 or less nodules
Implementation Method 2
interfaces between the primary particles, which become diffusion paths for lithium ions
Data Source
AI summary
A positive electrode active material according to the present invention includes a lithium composite transition metal oxide which has an amount of nickel among total metals excluding lithium of 50 mol% to 80 mol% and is in a form of a single particle composed of one single nodule or a pseudo-single particle that is a composite of 40 or less nodules; and a tungsten-containing coating layer formed on a surface of the lithium composite transition metal oxide, wherein a ratio (Li/W) of the number of moles of lithium to the number of moles of tungsten, which is measured by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis after performing a pretreatment under conditions of immersing the positive electrode active material in deionized water at 25°C for 1 hour, satisfies a range of 30 to 45.