"Chinese Membranes" Leading the World, Enjie Shares and the Battle for the "Heart Valve" of Lithium Batteries

Ask AI · How does Enjie Holdings balance the technical challenges of membrane thinness and safety?

Text / Wang Qiang

Early spring 2026, the National Two Sessions just concluded, and the blueprint of the “14th Five-Year Plan” is becoming clearer amid the enthusiastic discussions of deputies and committee members. When China’s non-fossil energy consumption share surpasses 20%, and policies actively promote green and low-carbon economic development, the deeper challenges of energy system transformation also emerge: how to develop and expand emerging industries like new energy, so that green electricity not only can be generated but also used effectively and reliably?

This is not only a grid issue but also a challenge for the lithium battery industry chain. In the “sandwich” structure of lithium batteries, the positive and negative electrode materials must not contact each other, or it will cause a short circuit and fire. The membrane is the key material that physically separates the positive and negative electrodes, allowing only lithium ions to pass through. It does not contribute to energy density but determines the safety baseline of the battery; it is as thin as a cicada’s wing but bears immense responsibility. Industry calls it the “heart valve” of lithium batteries.

While the world seeks energy transformation, in the inland Yunnan Yuxi, a smart factory is quietly operating. Rolls of silver-white film are steadily transported on a highly clean production line, ultimately becoming lithium battery separators only 5 microns thick. It is so thin—only one twentieth of an A4 sheet—that it can withstand puncture by hundreds of grams of weight without damage.

This is Enjie Holdings’ factory, also a microcosm of China’s new energy materials from catching up to leading.

Between Microns, a Heavy Responsibility

2026 marks the beginning of the “14th Five-Year Plan” and a critical sprint for China to achieve carbon peak by 2030. Currently, the national energy system is working around strategic tasks such as ensuring energy security, green low-carbon transformation, and building an energy powerhouse. Li Chuangjun, director of the New Energy and Renewable Energy Department of the National Energy Administration, proposed to promote the “14th Five-Year Plan” to expand and improve the quality of renewable energy and achieve reliable substitution. Behind this is a real-world test: the proportion of “green” energy in the power system is rapidly increasing, making the safety and reliability of devices like lithium batteries more important than ever.

The role of separators in lithium batteries resonates deeply with the phrase “reliable substitution.” They must not only isolate the positive and negative electrodes to prevent short circuits and fires but also, through their thickness, porosity, puncture strength, and other indicators, directly influence the battery’s energy density and rate performance. It can be said that without technological breakthroughs in separators, there would be no today’s high-energy-density power batteries. They are indispensable key materials in the process of the new energy industry from zero to one, and from one to hundred. Currently, Chinese separator manufacturers occupy nearly 90% of the global market share. In this field, Enjie has become a global leader. According to SNE Research data, from January to October 2025, Enjie maintained its position as the world’s top market share.

“Separators in batteries do not contribute to energy density, but in order to pack more active materials into limited space and improve energy density, we need to keep making separators thinner,” explains Jiao Lingkuan, Vice President of Enjie’s Global R&D Institute. Making them thinner means challenging physical limits. An ordinary A4 sheet is about 100 microns thick, while Enjie’s main products are only one twentieth of that. However, extreme thinness cannot come at the expense of safety. The core function of separators is to isolate the electrodes and conduct lithium ions; once broken, the battery short circuits and catches fire, with disastrous consequences.

Based on the core indicator of puncture resistance, Enjie proposed the concept of “micron with heavy responsibility”: even at a few microns thick, the separator can withstand puncture by hundreds of grams without damage. From 9 microns to 7 microns, then to 5 microns of wet-process separators, Enjie’s logic has always been to balance thinness, high strength, and fast conductivity. In August 2025, Enjie officially launched a new generation of 5-micron ultra-thin high-strength separators. Compared to conventional 7-micron products, the thickness was reduced by 28.5%, but puncture strength increased by 16.7%, reaching 550 gf.

In 2025, the lithium battery separator industry experienced a bottoming out and recovery. Enjie expects to achieve a net profit of 109 million to 164 million yuan for the year, turning losses into profits. Enjie’s main products are lithium battery separators, including base films and coated films, which have long accounted for over 80% of the company’s revenue. The performance turnaround is driven by Enjie’s “Three Highs and One Long” philosophy: high technology, high quality, high efficiency, and adherence to long-termism. In the face of industry price wars, Enjie’s management clearly rejects short-term thinking of “price to volume,” instead adopting a strategy of “differentiated competition + value upgrading.”

“Industry reshuffling is inevitable. We’re not afraid of price wars, but we refuse to engage in low-level repetition. The country’s ‘14th Five-Year Plan’ calls for ‘expanding volume with quality and reliable substitution,’ and we listen carefully and feel deeply,” says Li Xiaoming, founder and chairman of Enjie. “In the past twenty years, our mission was ‘from nothing to something, breaking monopolies.’ Today, Enjie’s mission has shifted to ‘from having to leading, driving transformation.’ Others are competing on thickness; we focus on strength, safety, and consistency, making the same products more reliable. That’s our moat.”

National Membrane Power: From Catching Up to Leading

Among the four main materials for lithium batteries, separators are the last to achieve domestic production and the most technically challenging. Why have they become one of the four main materials? How high is the technical barrier for wet-process separators? Enjie believes that the technical barriers mainly lie in four dimensions: material formulation, process precision, equipment capability, and consistency control. Coupled with high capital investment and long R&D cycles, new entrants must overcome barriers across the entire material, equipment, and process chain, while continuously facing the challenges of battery technology iteration.

First is the base film manufacturing process. From polymer material formulation to bidirectional stretching control, extraction technology, and heat setting, each step requires precise control. Next is micropore structure design: pore sizes need to be controlled at the nanometer level (usually 0.01–0.1 microns), with porosity between 30% and 50%. Too high reduces strength; too low affects ion conductivity. Third is coating technology: the dispersibility of ceramic, PVDF, and other coatings, and the precision of coating processes directly impact separator performance. Fourth is equipment and line integration: extrusion machines, stretching machines, extraction tanks, etc., need customized development. Imported equipment from Japan’s Steel Corporation and Germany’s Brückner are expensive and require complex maintenance. Lastly, consistency control: high-end separators require thickness tolerances within 1 micron (for example, a 7-micron separator should be within 6–8 microns). Variations in raw materials, temperature drift, and other factors during continuous production can cause performance differences, requiring real-time online monitoring.

Each of these hurdles can block most new entrants, but Enjie has already overcome them all. Looking back, Enjie’s growth story is also a story of China’s manufacturing breakthrough.

“To be honest, sometimes late at night I still think about the days when we first started making separators,” Li Xiaoming recalls. “Separators look like a plastic film, but they involve high polymers, nanoconduit formation, and precise coating—an extremely complex science. When we first debugged the equipment, many team members stayed in the workshop for months, eating and living there.”

The belief in making world-class separators sustains Enjie’s team’s resolve to “sit on the bench for ten years in the cold.” From material formulation to bidirectional stretching, from pore size control to coating breakthroughs, Enjie has gradually overcome the technical barriers of wet-process separators. Today, Enjie’s R&D is led by its global research institute in Shanghai, with a team of over 500 people from China, the US, Japan, Korea, and other countries. It includes institutions such as the Forward-looking Technology Research Institute, Product Development Center, and Process Technology Development Institute, covering materials, processes, equipment, and testing across the entire chain. As of February 2026, Enjie has accumulated 512 authorized patents, including 51 international patents, with 318 pending. The annual R&D investment is about 700 million yuan.

Enjie attaches great importance to talent development, continuously recruiting and cultivating potential talent internally. By 2025, several key personnel had been promoted to key positions at production bases and headquarters, injecting new vitality into the organization. Leveraging its multi-base, multi-business platform domestically and abroad, Enjie offers employees diverse development paths across fields and regions, broadening career growth and strengthening organizational resilience and collaboration. Through a dual approach of “internal training and external recruitment,” Enjie has built a talent ladder with a reasonable structure and diverse capabilities, providing talent support and intellectual backing for high-quality business development.

At the Enjie plant in Yuxi, Yunnan, you hardly see the scene of workers bustling in traditional manufacturing. Instead, highly clean environments operate automated equipment. This is an intelligent production base designed as a “lighthouse factory” following Industry 4.0 standards. Its core is a digital “superbrain”: engineers operate computers at the control center to monitor and coordinate the entire production line in real time. Behind this digital management, Enjie has digitized R&D, production, supply chain, sales, and service, building a business intelligence analysis system covering procurement, inventory, production, and finance. Using 147 indicators for data-driven management, it promotes a habit of “data-driven decision-making” among all staff.

Enjie believes that “the new quality productivity in separator industry is driven by technological innovation, underpinned by green and low-carbon principles, supported by intelligent manufacturing, and guided by global collaboration, enabling the industry to leap toward high quality, high resilience, and high added value.”

Through Cycles, Leading the Future

Enjie, as the world’s leading separator company, does not rest on its laurels. In December 2021, Enjie established Hunan Enjie Advanced New Materials Technology Co., Ltd. (“Hunan Enjie”), officially entering the solid-state battery materials field. Enjie chose the most promising sulfide route, known for its ultra-high ionic conductivity and good processability, considered the mainstream path for solid-state batteries. Major companies like Toyota Japan, LG Korea, and domestic leaders such as CATL, BYD, Cnano, and Guoxuan have all made moves in this area.

Regarding the so-called “next-generation battery,” solid-state batteries, there are many “disruption theories,” with concerns that their widespread adoption could make the separator industry obsolete overnight. Enjie’s view is clear: “Semi-solid still needs separators, full solid-state will take time. Semi-solid batteries still use separators, and Enjie’s products are already supplied in bulk to top companies like Weilan New Energy; full solid-state batteries will take longer to scale and industrialize, expected mainly for deep space, deep ocean, and other high-end niche fields before 2030, and won’t disrupt the current separator market in the short term.”

Li Xiaoming states, “A true industry leader must dare to revolutionize itself, so we started R&D on solid electrolytes and sulfide lithium early. If the solid-state era really arrives, Enjie will still be a core supplier in this field. Our vision is never just to hold onto a separator but to become a globally leading new energy materials company.”

Currently, Hunan Enjie has completed a 10-ton pilot line for high-purity sulfide lithium products, recognized by top clients, with small-batch shipments underway. The 10-ton solid electrolyte production line is operational with ton-level shipment capacity, and new electrolyte samples have been sent to leading domestic and international battery companies. Ultra-thin, high-toughness electrolyte membranes are in R&D and sampling stages, with conductivity and other indicators at industry-leading levels.

Enjie has reached strategic cooperation with Weilan New Energy, Guoxuan, and Enli Power. In 2025, Enjie signed a procurement framework agreement with Beijing Weilan New Energy for procurement shares from 2025 to 2030; also, an agreement with Enli Power to jointly develop high-performance electrolyte separators compatible with solid-state batteries.

Forward-looking technological deployment ultimately aims to land in a global market map. Enjie believes that true industry leadership involves not only defining the future technologically but also occupying a core position in the global industrial chain. In the face of increasingly complex international trade environments, Enjie’s strategy is “local service, global reach”: using localized capacity, teams, and services to deeply integrate into the global market.

Currently, Enjie’s global layout is taking shape. Its U.S. project is progressing steadily; the Hungary plant has reached cooperation with local top enterprises and begun supplying overseas customers. By employing local teams and strictly complying with local regulations, Enjie ensures steady overseas development.

From a local enterprise in Yuxi, Yunnan, to a global leader in the separator industry, Enjie started in 2010 under Li Xiaoming’s leadership, entering the lithium battery separator field. After 16 years of effort, from one separator factory to 13 now, based in China and expanding globally, the domestic market share of Chinese separators has increased from 4% to over 93%, making Enjie a world leader in lithium battery separators.

Enjie’s journey exemplifies the rise of China’s new energy industry chain. Li Xiaoming believes, “Let more new energy vehicles use safe, stable Enjie separators—that’s not just business, but a mission and responsibility for our generation toward global sustainable development.”

Editor: Shi Yan