Graphene-Coated Battery Anodes for Uniform 3D Surface Coverage
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Solution Overview
Problem
Existing methods struggle to form graphene on objects with uneven, complex, or curved surfaces, leading to incomplete and uneven graphene coatings, which limits the performance of secondary batteries due to gaps between carbon particles and reduced lithium ion occlusion and release capacity.
Innovation Solution
A method involving the dispersion of graphene oxide in a solution, using electrophoresis to deposit graphene oxide on the object's surface, followed by reduction to form a uniform graphene coating, allowing for effective coverage of complex surfaces and creation of a film-like carbon-based material that can be used as an electrode material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coating methods are used to form graphene on objects with uneven or complex surfaces, then the coating process is simple, but the graphene coating becomes incomplete and uneven, leading to gaps between carbon particles
Solution Approach 1:
The coating process is segmented into two distinct stages: first forming a graphene oxide coating, then reducing it to graphene. This segmentation allows each stage to be optimized independently, with the reduction stage transforming the uneven graphene oxide into uniform graphene that effectively covers complex surfaces without gaps.
Solution Approach 2:
The invention changes the physical and chemical parameters of the coating material by using graphene oxide (which can be uniformly deposited) and then altering its state through thermal or chemical reduction to convert it into graphene. This parameter change enables the coating to adapt to complex surface geometries while maintaining uniformity.
2Power
If particle size of active material is reduced to increase power, then conductive additive and binder are needed, but they decrease capacity per unit volume of electrode
Solution Approach 1:
The invention merges the functions of the active material and the conductive coating by forming graphene directly on the surface of the active material particles. This eliminates the need for separate conductive additives and binders, as the graphene coating itself provides both structural support and electrical conductivity, thereby preserving electrode volume for active material.
Solution Approach 2:
The graphene coating serves multiple functions simultaneously: it acts as a conductive additive to enhance electron transport, serves as a binder to hold particles together, and provides mechanical strength to prevent particle degradation. This multi-functionality eliminates the need for separate components that would otherwise occupy valuable electrode volume.
3Ease of manufacture
If graphene is formed on uneven surfaces using conventional methods, then the process is straightforward, but gaps remain between carbon particles reducing lithium ion occlusion and release capacity
Solution Approach 1:
The invention performs a preliminary action by first depositing graphene oxide, which has different properties than graphene and can be more easily and uniformly deposited on complex surfaces. This preliminary coating is then reduced in a subsequent step to form the final graphene structure, ensuring complete coverage before the transformation to the conductive graphene state.
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 method enables the formation of graphene on complex surfaces with uniform thickness, enhancing lithium ion diffusion paths and conductive networks, improving the efficiency and durability of secondary battery electrodes by preventing crushing and increasing lithium occlusion and release capacity.
Implementation Method 1
using electrophoresis to deposit graphene oxide on the object's surface
Implementation Method 2
followed by reduction to form a uniform graphene coating
Data Source
AI summary
To form graphene to a practically even thickness on an object having an uneven surface or a complex surface, in particular, an object having a surface with a three-dimensional structure due to complex unevenness, or an object having a curved surface. The object and an electrode are immersed in a graphene oxide solution, and voltage is applied between the object and the electrode. At this time, the object serves as an anode. Graphene oxide is attracted to the anode because of being negatively charged, and deposited on the surface of the object to have a practically even thickness. A portion where graphene oxide is deposited is unlikely coated with another graphene oxide. Thus, deposited graphene oxide is reduced to graphene, whereby graphene can be formed to have a practically even thickness on an object having surface with complex unevenness.