As battery manufacturing ramps up across North America, one critical but often overlooked component is gaining renewed attention: the separator.
In this edition of Battery Bits, we sat down with Emery Brown of Green New Energy Materials (GNEM) to discuss how separator technology is evolving, what customers care about in 2026 for EVs and energy storage, and why the U.S. supply chain may have reached an inflection point.
Battery Bits:
Today, we’re here with Green New Energy Materials. They are an American separator manufacturing company. We’re joined by Emery Brown. Emery, great to have you here.
Emery Brown:
Always a pleasure.
Battery Bits:
We’d love to get started by getting to know Green New Energy Materials (GNEM) a little better. GNEM was established in 2023, but your expertise clearly runs deeper than that. Can you tell us more about your company’s background?
Emery Brown:
Absolutely. While GNEM was established in the U.S. in 2023, we’re part of Senior’s global expansion. Senior is already the second-largest separator manufacturer in the world by volume-and soon to be the largest.
They were founded around 2003, so we’re bringing 20+ years of manufacturing experience to the U.S. market with 600 patents in the global portfolio. Our focus is really about strengthening the North American battery supply chain with advanced lithium-ion separators.
Battery Bits:
You’ve done business in the U.S. for 3 years at this point now then. What does your U.S. manufacturing footprint look like today?
Emery Brown:
Our facility in Denver, North Carolina is about 534,000 square feet, and we’re scaling alongside market demand. We expect to hire close to 500 employees over the next few years. In terms of capacity, we will have 20 production lines when the project is complete with an annual output of about 2 billion square meters. To put that into perspective, that’s roughly 370,000 football fields worth of separator material annually.
"To put that into perspective, that’s roughly 370,000 football fields worth of separator material annually. - Emery Brown, Green New Energy Materials
Battery Bits:
With that sort of scale, you must have a number of strategic partnerships supporting your U.S. expansion. Can you tell us more?
Emery Brown:
While I can’t speak to specific U.S. partnerships, we benefit from Senior’s global relationships. That includes companies like LG Energy Solution, Samsung SDI, and AESC.
We’re bringing that same level of collaboration and experience into the U.S. market.
Battery Bits:
The one question that will be on everyone’s mind knowing that GNEM is part of a Chinese company’s expansion: IRA tax credit eligibility. Domestic manufacturing incentive qualifications like 45X are top of mind. How is GNEM positioned?
Emery Brown:
It’s a moving target for the entire industry. GNEM was founded in alignment with IRA requirements, but policies continue to evolve. Right now, we’re working toward becoming OBBBA-compliant, which will better position us to serve customers focused on qualifying for domestic incentives.
Battery Bits:
Getting into the more technical details- for readers less familiar, in your own words, what does a separator actually do?
Emery Brown:
At its core, the separator does exactly what the name implies: it separates the anode and cathode electronically, while still allowing lithium ions to pass through. Modern batteries have evolved to require much more than a simple polymer film. At GNEM, we focus on coating technologies that improve mainly wettability, safety, and impedance. These three dimensions dictate the balancing act between energy density, power, safety, and manufacturability. You’ve heard me say this before, but I often call the separator the “unsung hero” of the lithium-ion battery.
Battery Bits:
Not all separators are created equal though. How do requirements differ between EV and energy storage customers?
Emery Brown:
For EVs, everything starts with cost and safety. After that, it depends heavily on the application:
- Long-range vehicles → prioritize energy density (thinner separators)
- Fast charging → prioritize porosity and interface engineering
- Long lifespan → prioritize coating stability
For energy storage systems (ESS), it’s more straightforward:
- Cost
- Safety
- Longevity
Because ESS projects are tied to financing and ROI, longevity and predictability become especially important.
"GNEM is bringing advanced separator manufacturing to the U.S. at scale, and we’re proud to support the supply chain. - Emery Brown, Green New Energy Materials
Battery Bits:
These are the dimensions that matter today for current applications. How do you see these requirements evolving over the next five years?
Emery Brown:
I see a major expansion of U.S. battery manufacturing, driven by three factors: energy storage for AI data centers, autonomous and semi-autonomous EVs, and rising costs and risks of importing batteries. On the product side, based on conversations with customers, EVs will shift toward fast charging and longevity, less focus on range. ESS will increasingly emphasize safety and long-term stability, especially as insurance and regulation tighten.
Battery Bits:
Can you walk us through dry vs. wet separator manufacturing?
Emery Brown:
When we say dry or wet, we’re really talking about how the base film is made.
The dry process is a dry extrusion of polymer, usually polypropylene, followed by stretching. It’s traditionally more cost-effective and gives good structural strength.
The wet process uses a solvent to dissolve polyethylene, then removes it to create pores. That gives better pore structure, better wettability, and often higher performance.
We’re seeing a shift toward wet processes as costs come down and performance becomes more important.
Battery Bits:
What are the main types of separator coatings today?
Emery Brown:
At a high level, you have ceramic coatings, polymer coatings, and composites.
- Ceramics improve safety, thermal stability, and mechanical strength.
- Polymers improve interface resistance and performance.
- Composites combine both.
We also have functional coatings, which are more specialized. For example, LATP for hybrid systems and aramid-based coatings for high-temperature stability.
It’s not really about trade-offs between them- it’s more about balancing performance, safety, cost, and manufacturability.
Battery Bits:
Anything else you’d like readers to take away?
Emery Brown:
First, GNEM is bringing advanced separator manufacturing to the U.S. at scale, and we’re proud to support the supply chain. Second, there’s a lot of uncertainty right now – policy changes, tariffs, tax credits – but I still believe the best days are ahead for the battery industry. We see a lot of good traction and think we have a good opportunity to deliver a domestically made product for the battery demand in the U.S. With AI-driven demand, electrification, and the push for domestic manufacturing, there’s a lot to be optimistic about.
