Graphene Conductive Additive Manufacturing for Battery Electrodes
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Solution Overview
Problem
Graphene's large specific surface area makes it difficult to disperse and aggregate, leading to poor functionality as a conductive additive in lithium-ion secondary batteries, and reduced graphene oxide (RGO) has defective structures affecting its conductivity.
Innovation Solution
A method involving a mixture of an active material, graphene compound, binder, and dispersion medium applied to a current collector, followed by drying, heat treatment, and thermal reduction using a reducing agent to enhance graphene's conductivity and prevent aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content of conductive additive is increased to increase contact points between active material and conductive additive, then the conductivity is improved, but the ratio of active material in the electrode is reduced, resulting in a reduction in charge and discharge capacity
Solution Approach 1:
The invention changes the physical form of the conductive additive from conventional particulate (acetylene black with several tens to hundreds of nanometers diameter) to two-dimensional expanded graphene. This parameter change in morphology allows the graphene to provide extensive contact surface area with active material particles while occupying minimal volume and weight, thereby improving conductivity without sacrificing active material content and battery capacity
Solution Approach 2:
The invention creates a composite structure where two-dimensional expanded graphene is combined with active material particles. The graphene forms a conductive network that envelops and connects active material particles, creating an efficient electron transport pathway. This composite approach allows for reduced conductive additive content while maintaining or enhancing conductivity, thus preserving more active material for higher capacity
2Reliability
If general particulate conductive additive such as acetylene black is used, then the conductive path can be formed, but the contact between conductive additive and active material is point contact, resulting in high contact resistance
Solution Approach 1:
The invention transitions from zero-dimensional particulate conductive additives (acetylene black particles) to two-dimensional expanded graphene structures. This dimensional change enables the conductive additive to wrap around and make surface contact with active material particles rather than point contact, significantly reducing contact resistance and improving electron transfer efficiency
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 improves the conductivity and dispersibility of graphene, leading to a more efficient conductive path in the battery, increasing the battery's capacity and reducing contact resistance.
Implementation Method 1
the graphene compound in the mixture is reduced by a chemical reaction using a reducing agent
Implementation Method 2
a thermal reduction treatment is performed on the mixture at a temperature higher than the temperature of the heat treatment
Implementation Method 3
a drying treatment is performed on the mixture
Data Source
AI summary
A method for manufacturing a novel electrode is provided. The method includes the steps of applying, to a current collector, a mixture comprising an active material, a conductive additive comprising a graphene compound, a binder, and a dispersion medium; performing a drying treatment on the mixture; performing a heat treatment on the mixture at a temperature higher than a temperature of the drying treatment; reducing the graphene compound in the mixture by a chemical reaction using a reducing agent; and performing a thermal reduction treatment on the mixture at a temperature higher than the temperature of the heat treatment.