Why Is Conductive Silver Paste Or Pressure Used In Coin-Cell Assembly? Optimize Supercapacitor Performance

The primary objective is minimizing contact resistance. Applying conductive silver paste or utilizing a laboratory press ensures a robust electrical connection between the current collector and the battery casing. This process optimizes the electron transfer path and mitigates poor contact caused by irregular particle shapes—common in recycled materials like Mn2O3-C-ZnO2 (MCZ)—thereby maximizing specific capacitance performance.

Core Takeaway: By eliminating microscopic voids and ensuring uniform physical adhesion, these techniques significantly reduce equivalent series resistance (Rs) and charge transfer resistance (Rct). This reduction is critical for ensuring the structural integrity, accurate capacitance measurement, and long-term cycling stability of the device.

The Role of Conductive Silver Paste

Bridging Microscopic Irregularities

Current collectors and active materials are rarely perfectly smooth at the microscopic level. Silver paste acts as a conductive bridge, filling voids that would otherwise act as insulating gaps.

This is particularly crucial when dealing with recycled battery materials, such as MCZ. These materials often feature irregular particles that do not naturally sit flush against the casing.

Optimizing Electron Transfer

Without a conductive medium, electron flow is restricted to the high points where materials physically touch. Silver paste increases the effective contact area.

By optimizing the electron transfer path, the paste ensures that the full surface area of the electrode contributes to charge storage, rather than just isolated contact points.

The Function of the Laboratory Press

Ensuring Tight Physical Contact

A laboratory press applies uniform pressure to the "sandwich" assembly of the electrode, separator, and casing.

This mechanical force is decisive for eliminating internal contact resistance. It forces the layers together, ensuring the active material is tightly loaded onto the current collector.

Maintaining Structural Integrity

During long-term cycling tests, components can shift or loosen, leading to inconsistent data.

High-precision sealing and pressing create a stable unit that prevents structural loosening. This stability is vital for the repeatability of cycle life and rate performance data.

Expelling Air and Preventing Leakage

Pressing the assembly helps expel excess air bubbles trapped between layers, which can impede ion transport.

Furthermore, precise pressure control is required to seal the device effectively. This prevents the leakage of gel or liquid electrolytes, ensuring the device remains safe and chemically stable.

Understanding the Trade-offs

The Risk of Over-Compression

While pressure reduces resistance, excessive force can be detrimental.

Over-compressing the device may crush the porous structure of the active material or puncture the separator. This can restrict ion transport or cause internal short circuits, negating the benefits of improved contact.

Consistency in Application

The application of silver paste must be uniform. Thick or uneven layers can alter the internal geometry of the cell.

Similarly, the pressure applied via the press must be constant and uniform across the entire surface area. Inconsistent pressure leads to localized current hotspots and uneven aging of the device.

Optimizing Your Assembly Protocol

To achieve reliable results, tailor your assembly process to your specific performance metrics:

If your primary focus is maximizing specific capacitance: Prioritize the application of silver paste to mitigate contact issues caused by irregular particle shapes, ensuring every particle contributes to energy storage.
If your primary focus is long-term cycling stability: Focus on precise, uniform pressure control during sealing to prevent electrolyte leakage and maintain structural bonding over thousands of cycles.

A high-performance supercapacitor requires a balance of chemical connectivity and mechanical stability to ensure low resistance and high efficiency.

Summary Table:

Feature	Function in Assembly	Impact on Performance
Silver Paste	Fills microscopic voids & bridges irregular particles	Reduces Rs and Rct; increases specific capacitance
Lab Press	Ensures tight physical contact & mechanical bonding	Maintains structural integrity & cycling stability
Pressure Control	Expels air bubbles & seals cell casing	Prevents electrolyte leakage & ensures ion transport
Optimization	Uniform application & balanced force	Prevents material crushing & localized current hotspots

Elevate Your Battery Research with KINTEK Precision

High-performance supercapacitors demand a perfect balance of chemical connectivity and mechanical stability. KINTEK specializes in comprehensive laboratory pressing solutions designed to eliminate contact resistance and ensure the structural integrity of your coin cells.

Whether you are working with recycled materials or cutting-edge energy storage research, our extensive range of equipment—including manual, automatic, heated, multifunctional, and glovebox-compatible models, as well as cold and warm isostatic presses—is engineered for the precision your data requires.

Don't let inconsistent pressure or poor contact compromise your specific capacitance results. Contact KINTEK today to find the ideal pressing solution for your laboratory and take your battery research to the next level.

References

T. Kedara Shivasharma, Babasaheb R. Sankapal. Device grade solid-state pouch and coin cell supercapacitors dual assembly using consumed battery waste to best utilization. DOI: 10.1038/s41598-025-96426-4

This article is also based on technical information from Kintek Press Knowledge Base .