Graphene-HE-NCM Composite via Low-Temp Thermal Decomposition
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Solution Overview
Problem
Current methods for producing graphene/HE-NCM composites face challenges in achieving uniform distribution of graphene and large-scale production due to the need for special atmospheres and high temperatures, which also limit the electrochemical performance of lithium ion batteries.
Innovation Solution
A method involving the thermal decomposition of graphene oxide/HE-NCM at low temperature in a short time, using ultrasonication and lyophilization to disperse HE-NCM particles in a graphene oxide solution, followed by thermal decomposition, allowing for a uniform and cost-effective production of graphene/HE-NCM composites suitable for large-scale production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong reductants or high temperature solvothermal reduction is used to reduce graphene oxide, then graphene/HE-NCM composite can be obtained, but transitional metals are reduced and the method is difficult to scale up
Solution Approach 1:
The patent changes the temperature parameter from high temperature (solvothermal reduction) to low temperature (thermal decomposition at 300-400°C), and changes the chemical environment from strong reducing medium to air atmosphere, thereby avoiding metal reduction while achieving graphene reduction and improving scalability
Solution Approach 2:
The patent replaces the chemical reduction method (using strong reductants like hydrazine or sodium borohydride) with a thermal decomposition method, substituting chemical reduction mechanisms with thermal energy-driven decomposition, which eliminates the need for strong reductants and special atmospheres
2Ease of manufacture
If mechanical mixing of pristine powder and graphene solution is used, then the process is simple, but uniform distribution of graphene in HE-NCM particles cannot be achieved
Solution Approach 1:
The patent applies preliminary action by first dispersing HE-NCM particles in graphene oxide solution before thermal decomposition, ensuring uniform distribution of graphene oxide on particle surfaces prior to the reduction step, which guarantees uniform graphene distribution in the final composite
Solution Approach 2:
The patent creates a composite structure where graphene oxide coats HE-NCM particles uniformly before reduction, forming a core-shell like structure that ensures intimate contact and uniform distribution of conductive graphene throughout the composite material
3Reliability
If high temperature and special atmosphere are employed for graphene reduction, then graphene/HE-NCM composite is obtained, but large-scale production becomes difficult
Solution Approach 1:
The patent changes the temperature parameter from high temperature to low temperature (300-400°C thermal decomposition), and changes the atmosphere parameter from special reducing atmosphere to air, thereby simplifying the process conditions and enabling large-scale production while maintaining composite quality
Solution Approach 2:
The patent utilizes air (oxygen) as the oxidizing agent for thermal decomposition, allowing the process to proceed in ambient atmosphere without requiring special reducing gas environments, which significantly improves scalability and reduces operational complexity for large-scale production
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
This method results in enhanced electrochemical performance and improved conductivity of the graphene/HE-NCM composite, leading to increased discharge capacity and cyclability, making it suitable for lithium ion batteries.
Implementation Method 1
using ultrasonication and lyophilization to disperse HE-NCM particles in a graphene oxide solution
Implementation Method 2
thermal decomposition of graphene oxide/HE-NCM at low temperature in a short time
Implementation Method 3
using ultrasonication and lyophilization to disperse HE-NCM particles in a graphene oxide solution
Data Source
Figure 1A~1C
Figure 2
Figure 3~4
AI summary
The present invention relates to a method for preparing a graphene/HE-NCM composite, wherein more than one HE-NCM particles of the formula (1) xLi2MnO3•(1-x)LiNiyCozMn1-y-zO2, wherein 0<x<1, 0<y<1, and 0<z<1, are in electrical contact with each other via one or multiple graphene flakes, said method including: a) dispersing HE-NCM particles in a solution of graphene oxide by ultrasonication to give a dispersion; b) lyophilization of the dispersion to give a graphene oxide/HE-NCM composite; c) thermal decomposition of the graphene oxide/HE-NCM composite to give the graphene/HE-NCM composite. The present invention further relates to a graphene/HE-NCM composite for lithium ion battery prepared by said method, an electrode material and a lithium ion battery comprising said graphene/HE-NCM composite.