How to choose the right lithium-ion battery separator material

When evaluating lithium-ion battery components, the separator deserves careful attention. The right separator material can help improve battery performance, support faster charging, enhance thermal safety, and contribute to longer service life. Because different applications have different performance requirements, understanding how to select the right separator is a critical step in battery design.

What Should You Look for in a Battery Separator?

When evaluating a lithium-ion battery separator, there are a few key characteristics to consider:

Porosity- Porosity affects how easily lithium ions can move through the battery. Higher porosity can support faster charging, improved discharge rates, and better overall battery performance.

Thermal Stability- A separator must maintain its structure when exposed to elevated temperatures. Materials with strong thermal stability may help maintain separator integrity during elevated-temperature conditions.

Electrolyte Retention- A separator's ability to absorb and retain electrolyte plays an important role in maintaining consistent ion transport and long-term battery performance.

Mechanical Strength- Separators must withstand manufacturing and operating stresses while continuing to keep the battery's electrodes safely separated.

Consider the End Application

An optimal separator solution exists for both the battery design and the specific use case, the best separator for one application may not be the best choice for another . A battery designed for a high-performance drone has different requirements than a battery used in an electric vehicle or a grid-scale energy storage system. Some applications prioritize rapid charging and high-power output, while others place greater emphasis on long-duration performance and safety.

When selecting a separator material, it's important to consider:

• Required charge and discharge rates
• Battery chemistry
• Operating environment
• Safety expectations
• Long-term performance goals

Understanding the Trade-Offs

One of the most common challenges in battery design is balancing performance and

safety. Thinner separators can improve energy density and power output, but reducing thickness too aggressively can also reduce the margin for error. Likewise, some conventional separator technologies use coatings to improve safety, but those coatings can restrict ion flow and impact performance. The goal is not to maximize a single property. It's to find the right combination of conductivity, safety, durability, and efficiency for the intended application.

Why OmniSep™?

The same factors that guide separator selection are what shaped the development of

Magnera's OmniSep™ platform. Designed for demanding lithium-ion battery applications, OmniSep offers high porosity, strong electrolyte retention, high ionic conductivity, and enhanced thermal safety characteristics 1 . The platform is being evaluated for use across a range of applications, including electric vehicles, energy storage systems, aerospace, defense, and consumer electronics.

By combining performance, safety, and flexibility, OmniSep helps battery manufacturers select a separator solution that is tailored to their specific application and requirements.

As battery technologies continue to evolve, separator selection will remain a critical factor in achieving the right balance of performance, safety, and reliability. Whether you're developing batteries for electric vehicles, energy storage systems, consumer electronics, or other advanced applications, Magnera's battery materials team can help identify the right separator solution for your needs.

To learn more about OmniSep™ and Magnera's battery separator capabilities, contact us at [email protected] or visit magnera.com/contact.

¹ Based on internal laboratory testing conducted by Magnera under specified test conditions. Results may vary depending on battery design, chemistry, and operating conditions.