Graphene Ternary Composite for Li-Ion Batteries
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Solution Overview
Problem
Current methods for modifying ternary materials with graphene to improve rate and cycling performance in lithium ion batteries are inefficient, particularly due to issues like poor conductivity and environmental incompatibility, and are not suitable for industrial production.
Innovation Solution
A method involving mixing ternary materials with graphene oxide in an organic solvent, followed by a reduction reaction and annealing in an inert atmosphere to form a graphene/ternary material composite with a three-dimensional network structure, enhancing mechanical flexibility and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ternary materials are modified with graphene using conventional methods, then conductivity is improved, but the rate performance remains poor and the process is not suitable for industrial production
Solution Approach 1:
The patent creates a composite material system combining ternary cathode material particles with graphene sheets formed in situ on their surfaces. This composite structure provides both the high capacity of ternary materials and the high conductivity of graphene, resolving the contradiction between improving conductivity and maintaining rate performance.
Solution Approach 2:
Graphene acts as an intermediary conductive network that bridges isolated ternary material particles, enabling efficient electron transport throughout the electrode. This intermediary conductive pathway allows the electrode to maintain high rate performance while benefiting from improved overall conductivity.
2Adaptability or versatility
If graphene oxide is used as raw material for modification, then dispersibility is improved, but the modification process becomes complex and unsuitable for industrial production
Solution Approach 1:
The patent extracts and eliminates the complex multi-step processing procedures from conventional methods, retaining only the essential in situ reduction step. This simplification removes unnecessary complexity while preserving the dispersibility benefits of using graphene oxide as a precursor.
Solution Approach 2:
The patent changes the processing parameters by conducting the reduction reaction under simple hydrothermal or solvothermal conditions with controlled temperature and time. This parameter optimization maintains good dispersibility while making the process suitable for industrial production by eliminating complex steps.
3Adaptability or versatility
If water-based solvents are used for graphene modification, then dispersibility is maximized, but water reacts with lithium oxide on ternary material surfaces causing degradation
Solution Approach 1:
The patent introduces an organic solvent as an intermediary medium that enables graphene oxide dispersal without direct water contact with the ternary material surface. This intermediary solvent layer prevents harmful reactions while maintaining the dispersibility advantages of aqueous-based processing.
Solution Approach 2:
The patent converts the potential harm of water reactivity into a benefit by using organic solvents that prevent surface degradation while still allowing effective graphene oxide dispersion and reduction. The solvent choice transforms a chemical compatibility issue into a process advantage.
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 approach significantly improves the rate and cycling performance of ternary materials, making them more suitable for industrial production while being environmentally friendly and cost-effective.
Implementation Method 1
adding a reducing agent to the mixed dispersion from step (a), and carrying out a reduction reaction at a reduction temperature of 80-160° C. while stirring
Implementation Method 2
drying and then annealing the mixture at a low temperature in an inert atmosphere to obtain a graphene/ternary material composite having a three-dimensional network structure
Data Source
AI summary
Provided is a method for preparing a graphene/ternary material composite for use in lithium ion batteries, comprising the following preparation steps: (a) mixing a ternary material and a graphene oxide powder in an organic solvent to form a mixed dispersion; (b) adding a reducing agent to the mixed dispersion from step (a), and carrying out a reduction reaction at a reduction temperature of 80-160° C. while stirring, to obtain a reduction reaction mixture after a reduction time of 60-240 min; and (c) evaporating the solvent from the reduction reaction mixture from step (b) while stirring, and drying and then annealing the mixture at a low temperature in an inert atmosphere to obtain a graphene/ternary material composite having a three-dimensional network structure. Also provided is a graphene/ternary material composite prepared by using this method.