Battery Separators

What it is

A separator is a thin porous polymer film that keeps a battery's anode and cathode from touching while letting lithium ions pass. Makers use a wet process or a dry process, and often add a ceramic or polymer coating.

Where China stands

Senior Technology says Chinese companies held over 92% of the global separator market in 2025, with Japanese, American and Korean makers losing share, and projects 105 billion square metres of global shipments by 2030, 100 billion of them from Chinese makers, citing XinLuo Lithium Battery data. These are its own statements (2026 interim report, p. 13).

Two listed companies lead:

• SEMCORP (恩捷股份, 002812.SZ) says it has the world's largest wet-process capacity and is the world's largest separator supplier by shipments. Its first-half 2026 revenue was ¥8.67bn, 87.9% of it from separators, and net profit was ¥820.3m against a loss of ¥93.1m (2026 interim report, pp. 8, 11, 14).
• Putailai (璞泰来, 603659.SH) coated 7.946 billion square metres of separator in the half, up 66.47%, which it puts at 36.45% of global wet-process shipments (its own calculation), and shipped 1.027 billion square metres of base film, up 94.69% (2026 interim report, p. 12).
• Senior Technology (星源材质, 300568.SZ) makes dry, wet and coated separators. Its revenue rose 39.7% to ¥2.65bn and its net profit doubled to ¥204.0m (p. 9).

From price war to recovery

SEMCORP says the industry had suffered price pressure from capacity added all at once, customers' cost reduction demands and competition, but that prices have stabilised and risen and supply of mid- and high-end separators is tightening (SEMCORP report, pp. 10, 11). Senior says the industry has left a period of overcapacity and low-price competition for a tighter balance with prices stabilising and rising (Senior report, p. 13). SEMCORP's separator gross margin rose 17.99 points in a year (p. 13).

Demand drivers cited are power battery installations of 608.5 GWh, up 20.0%, and storage battery shipments of 461.3 GWh, up 71.0% in the half (SEMCORP p. 11).

Our view: for separators the first half of 2026 shows a price recovery after a price war, not a change in market structure. Both makers say prices have stabilised, and a return of the all-at-once capacity additions that SEMCORP blames for the earlier price pressure would test that.

What to watch

• Pricing. Both companies say prices have stabilised and risen. A renewed price war would show in the next report's margins.
• Storage demand. Storage battery shipments are growing more than three times as fast as power battery installations (SEMCORP p. 11).
• Consolidation. In September 2026 SEMCORP agreed to buy SK ie technology's Jiangsu separator unit for a base ¥400m, and bought out EVE's 45% of their Hubei Enjie joint venture for ¥1.15bn, so it now owns that plant outright (announcement of 11 September; announcement of 28 September).
• Overseas sales. SEMCORP's overseas sales were ¥1.56bn, 17.95% of its revenue (p. 14).