NCM Hydroxide Core-Shell Structure for Better Rate Capability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion batteries using nickel cobalt manganese hydroxide and nickel cobalt lithium manganate cathode materials exhibit poor rate capability and high-temperature storage performance.
Innovation Solution
A method involving the mixing of water-soluble nickel, cobalt, and manganese ions with a strong base and ammonium hydroxide in an inert atmosphere, followed by a pulse current coprecipitation reaction with Ag powder to form a nickel cobalt manganese hydroxide with a compact core and loose, porous outer layer, which is then calcined with a lithium source to produce a nickel cobalt lithium manganate cathode material with improved structural properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional complex-precipitation method is used to prepare nickel cobalt manganese hydroxide, then the preparation process is simple, but the battery exhibits poor rate capability and high-temperature storage performance
Solution Approach 1:
Ag powder is introduced as an intermediary substance during the coprecipitation reaction. The Ag powder acts as a conductive inducer and template that facilitates the formation of a loose and porous outer layer on the hydroxide particles, thereby improving battery performance without significantly complicating the preparation process
Solution Approach 2:
The invention deliberately creates a porous structure in the nickel cobalt manganese hydroxide particles by using Ag powder as a template during coprecipitation. The porous outer layer with loose structure allows better electrolyte penetration and ion transport, directly addressing the poor rate capability and high-temperature storage performance issues
2Quantity of substance
If compact nickel cobalt manganese hydroxide particles are formed, then the material has high energy density, but the battery rate capability deteriorates
Solution Approach 1:
The invention applies local quality by creating a heterogeneous particle structure with a compact core and a loose porous outer layer. The compact core maintains high energy density, while the porous outer layer enhances rate capability by facilitating ion and electrolyte access. This spatial differentiation of structure properties resolves the contradiction between energy density and rate capability
3Reliability
If pulse current coprecipitation with Ag powder is used, then the battery rate capability and high-temperature storage performance are improved, but the preparation process complexity increases
Solution Approach 1:
The invention uses pulse current instead of direct current during the coprecipitation process, representing a parameter change in the electrical field. This pulse current approach, combined with Ag powder addition, creates the desired porous structure while keeping the process relatively simple by modifying existing coprecipitation parameters rather than introducing entirely new complex equipment or procedures
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 resulting lithium ion battery demonstrates enhanced energy density and rate capability, with specific surface areas and porosity levels optimizing battery performance.
Implementation Method 1
mixing a water solution A comprising water-soluble nickel, cobalt and manganese ions with a water solution B comprising strong base, and ammonium hydroxide in inert atmosphere to take a complex-precipitation reaction, and then adding Ag powder to take a pulse current coprecipitation reaction
Implementation Method 2
mixing a water solution A comprising water-soluble nickel, cobalt and manganese ions with a water solution B comprising strong base, and ammonium hydroxide in inert atmosphere to take a complex-precipitation reaction
Data Source
Figure 1~2
Figure 3~4
AI summary
The disclosure discloses a nickel cobalt manganese hydroxide, a cathode material, a preparation method thereof and a lithium ion battery. The nickel cobalt manganese hydroxide comprises a core and an outer layer covering the outside of the core. The core comprises flaky particles, the D50 particle diameter of the flaky particles in the core is 5-8 µm, and the D50 particle diameter of particles in the outer layer is 0.1-5 µm.