How Particle Size Affects Graphene’s Performance in Conductive Applications

🧭 Introduction: Why Particle Size in Graphene Matters

When we talk about graphene in industrial applications, most people focus on concentration, purity, or surface chemistry. But one often-overlooked factor has a surprisingly significant impact: particle size.

Whether in battery slurries, conductive coatings, polymer composites, or thermal films, the size of individual graphene sheets and aggregates directly influences performance outcomes like conductivity, dispersion stability, and mechanical properties.

This article dives into how particle size affects graphene’s behavior — and how engineers and formulators can choose the right size range for their target application.

📏 Section 1: What Does “Particle Size” Mean in Graphene?

Graphene is a two-dimensional material, meaning it has extremely thin thickness (typically <5 nm), but lateral size (width/length) can range from tens of nanometers to hundreds of microns.

In industry, we generally refer to the hydrodynamic diameter or D90 value (i.e., the diameter below which 90% of particles fall), typically measured by laser diffraction or dynamic light scattering (DLS).

Common Ranges:

• Small-flake graphene (0.2–2 µm): Higher surface area, better dispersion, but may lower electrical connectivity

• Medium-size graphene (2–20 µm): Balanced between performance and processing

• Large-flake graphene (20–100 µm+): High conductivity, but hard to disperse and may clog equipment

🧪 Section 2: Particle Size vs. Electrical Conductivity

Electrical conductivity in graphene-based systems depends on electron mobility between particles. Larger graphene sheets tend to:

• Form longer, uninterrupted conduction paths

• Require fewer interparticle junctions (which introduce resistance)

• Provide better percolation networks in composites

In practice, this means that larger flake graphene tends to deliver higher conductivity at the same loading level, especially in dry films or compressed pellets.

Example Data (same loading, epoxy resin matrix):

👉 Takeaway: For antistatic or EMI shielding applications, mid-to-large flake size is preferred.

🧫 Section 3: Particle Size vs. Dispersibility

While large flakes help conductivity, they also come with challenges:

• Poor dispersibility: Large flakes tend to aggregate or sediment in solvents or resin blends

• High shear requirement: Needs ultrasonic or high-speed mixing to break agglomerates

• Nozzle clogging risk: In spray coatings or inkjet systems, large particles can block flow paths

Conversely, small particle RGO disperses easily, stays suspended longer, and creates more uniform coatings — though conductivity may be sacrificed slightly.

This creates a trade-off: formulators must choose between processability and performance, or seek hybrid solutions.

🧪 Section 4: Role in Composite Reinforcement

For mechanical enhancement of polymers (like adding strength or modulus), smaller particle graphene is often more effective because:

• They disperse more uniformly

• They create more surface contact with the matrix

• They act as nanoscale reinforcements across microcracks

In contrast, larger flakes may not interact as efficiently with polymer chains and may cause stress concentration points if poorly dispersed.

Thus:

• Battery applications → mid to large flake for conductivity

• Coatings (spray, dip) → small-medium flakes

• Plastic composites → nano-platelet or small flakes

• 3D printing filaments → smaller flakes preferred for filament extrusion

🏭 Section 5: Application-Specific Guidance

✅ 1. Water-Based Conductive Coatings

• Ideal particle size: 5–20 µm

• Reason: Balances electrical percolation with sprayability and stability

• GrapheneRich Recommendation: GR-RGO Dispersion (~16 µm D90)

✅ 2. Lithium-Ion Battery Anode Slurries

• Ideal particle size: 5–30 µm (often combined with CNTs)

• Reason: Improves electronic conductivity, helps maintain conductive networks during cycling

• GrapheneRich Hybrid: Graphene + MWCNT composite powders

✅ 3. Thermal Interface Materials (TIM)

• Ideal: Large flakes (>30 µm) or vertically aligned stacks

• Reason: Enhances in-plane and through-plane thermal conductivity

✅ 4. 3D Printable Graphene-Polymer Filaments

• Ideal: Nano-sized or <2 µm flakes

• Reason: Disperses in PLA or TPU without affecting filament smoothness

📦 Section 6: Our Flagship Product – GrapheneRich’s RGO Conductive Powder

We currently supply a small-to-mid flake size graphene oxide powder, pre-reduced and optimized for coatings, batteries, and composite use.

Product Summary:

• Average Particle Size (D90): ~16 µm

• BET Surface Area: ~120 m²/g

• C/O Ratio (XPS): ~4–6

• Bulk Conductivity: 200–300 S/m

• Form: Dry powder or aqueous dispersion (0.5–5 mg/mL)

📦 Customization Available:
We also provide screened size distributions upon request:

• <5 µm

• 5–15 µm

• 20–50 µm

📩 Request TDS or MSDS here

❓ Section 7: Common Questions on Particle Size

Q1: Why not just use the largest graphene flake possible?
Because larger flakes are difficult to mix and may cause defects in coatings or resins. In some applications (like inkjet), they are simply not usable.

Q2: What is the optimal size for EMI shielding composites?
Generally 10–25 µm works well, especially in combination with carbon nanotubes to form conductive bridges.

Q3: How does size affect dispersion shelf life?
Smaller particles remain suspended longer, while larger particles may sediment within 2–3 days unless re-agitated.

Q4: Can I mill down your product to smaller size?
Yes, but we recommend caution: excessive milling can damage the graphene structure, lowering conductivity. We can provide pre-sorted sizes directly.

✅ Conclusion: Size Isn’t Everything, But It Matters More Than You Think

Particle size in graphene isn’t just a technical detail — it’s a performance driver. It affects conductivity, dispersion, mechanical reinforcement, processability, and ultimately your final product’s success.

Whether you’re formulating an antistatic coating, optimizing battery slurries, or upgrading plastics, GrapheneRich’s custom-size solutions give you the flexibility to choose what works best.

🔗 Next Steps
📨 Contact us to request:
✅ Technical datasheets
✅ Customized flake size samples
✅ Mixing/dispersing advice
✅ Application compatibility testing