Cathode lead-out materials for tantalum/aluminum capacitors: the Betely silver paste and carbon paste product lines.

2026-07-24 09:51

From fast charging for smartphones and 5G base stations to new‑energy vehicles and AI servers, capacitors—indispensable passive components in electronic circuits—are ubiquitous. They perform critical functions such as energy storage, filtering, decoupling, and resonance. The performance of a capacitor largely hinges on its electrode materials. Conductive silver pastes and conductive carbon pastes not only influence key parameters like equivalent series resistance (ESR), leakage current, and capacitance, but also directly determine the device’s reliability under demanding conditions, including high frequencies, elevated temperatures, and high humidity.

Betely has long been dedicated to the field of conductive materials. In response to the demand for cathode lead-out materials in tantalum and aluminum capacitors, it has developed a comprehensive portfolio of conductive pastes covering processes such as dip coating, dispensing, and screen printing, providing customers with end-to-end material solutions.

Product 1: Silver Paste for Impregnating Tantalum/Aluminum Capacitors (SF-2500/2600 Series)

For tantalum capacitors and multilayer aluminum capacitors, the cathode lead‑out process requires first forming a cathode material layer—manganese dioxide or a conductive polymer—on the surface of the tantalum or aluminum core, followed by impregnation with carbon paste and silver paste to establish a reliable external electrode. The compactness of the silver‑paste coating, its electrical conductivity, high‑temperature stability, and its compatibility with the carbon‑paste layer all directly determine the capacitor’s equivalent series resistance (ESR), leakage current, and overall reliability.

SF-2500 Series: Solid content ≥ 80%, viscosity 10,000–25,000 mPa·s, suitable for thick-film coating applications;
SF-2600 Series: Solid content ≥ 45%, viscosity 2,500–5,000 mPa·s, suitable for low-viscosity application requirements.

The resistivity of both products can reach levels below 3 × 10⁻⁵ Ω·cm, effectively supporting the design of capacitors that require low ESR values.

Product 2: Capacitor Impregnation Carbon Slurry (SF-162X Series)

In the electrode structure of a capacitor, carbon paste is used in conjunction with silver paste to form a complete electrode system. Carbon paste typically serves as a protective or transition layer; it must exhibit excellent compatibility with both the silver‑paste layer and the cathode material layer, while also possessing superior electrical conductivity and thermal stability to prevent silver migration and interfacial degradation.

The Betely SF-162X series impregnation carbon paste is meticulously formulated with high-performance resins and highly conductive carbon powders, specifically developed for dip‑coating applications. It delivers a uniformly impregnated surface layer and a smooth, even finish.

Project	Parameter
Viscosity	30~60 mPa·s
Curing conditions	130℃ × 20 min
Resistivity	≤8×10⁻³ Ω·cm

Suitable for the negative electrode materials of tantalum capacitors and multilayer aluminum capacitors, with excellent compatibility with the polymer layer and the silver paste layer.

Product 3: Stacked Aluminum Edge‑Coated Silver Paste (SF‑2680 Series)

For the edge‑spotting process used in multilayer aluminum capacitors, Betely has launched the SF‑2680 series edge‑spotting silver paste. This halogen‑free, bake‑out‑type conductive paste exhibits high thixotropy, strong adhesion, excellent conductivity, superior water resistance, and outstanding weatherability, making it ideally suited for coating the negative electrode material in multilayer aluminum capacitor products.

Project	Parameter
Viscosity	8000~15000 mPa·s
Curing conditions	150℃ × 60 min
Specific resistance	≤3×10⁻²Ω·cm

App Market and Industry Prospects

Currently, emerging applications such as AI servers, 800V fast‑charging platforms for new‑energy vehicles, and 5G infrastructure are scaling up rapidly, driving sustained growth in demand for high‑performance capacitors. According to industry research firms, the global tantalum capacitor market is projected to maintain a compound annual growth rate of approximately 5.9% between 2025 and 2030. Meanwhile, LTCC technology, with its superior high‑frequency performance and high integration density, is seeing steadily increasing adoption in RF front‑end modules, automotive electronics, and other sectors, directly boosting demand for corresponding electrode pastes.

Betely has established a comprehensive product portfolio in the field of capacitor conductive pastes, covering two major technological pathways: low‑temperature baking types (impregnation silver paste, impregnation carbon paste, edge‑dotting silver paste) and high‑temperature sintering types (internal electrode silver paste, terminal electrode silver paste, via‑filling silver paste), along with dedicated diluents and technical support services. Its products comply with environmental regulations such as halogen‑free and RoHS standards and are compatible with mainstream capacitor manufacturing processes both domestically and internationally.

Pad printing, dispensing, laser marking, dip coating… How do you choose the right conductive paste for each process?

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