Apexazole® SPBI Film

Sulfonated polybenzimidazole (SPBI) proton exchange membranes are high-performance membrane materials developed by Zhongke Jinding through sulfonation modification of conventional PBI membranes. By introducing sulfonic acid groups (-SO₃H) into the PBI backbone, SPBI achieves a substantial enhancement in proton conductivity, making it a key technological advancement in the field of proton exchange membranes.

Product Details

Sulfonated polybenzimidazole (SPBI) proton exchange membranes are high-performance materials developed by Zhongke Jinding through sulfonation modification of conventional PBI membranes. By introducing sulfonic acid groups (–SO₃H) into the PBI backbone, SPBI achieves a substantial enhancement in proton conductivity, making it a key technological direction in the field of proton exchange membranes. The structural design of SPBI membranes balances both chemical stability and proton conduction efficiency. On one hand, SPBI retains the aromatic heterocyclic structure of the PBI backbone, inheriting its excellent thermal stability—with a decomposition temperature exceeding 450°C—and robust mechanical strength. On the other hand, the incorporation of sulfonic acid groups creates continuous hydrated proton‑transport pathways within the membrane, significantly boosting proton conductivity and ensuring reliable performance even under low‑temperature, low‑humidity conditions. Compared with traditional perfluorosulfonic acid membranes (e.g., Nafion), SPBI offers several competitive advantages: in terms of cost, SPBI employs a non‑fluorinated aromatic heterocyclic architecture, with widely available raw materials and substantially lower production costs; in performance, the density of sulfonic acid groups in SPBI can be finely tuned via the degree of sulfonation to meet the demands of varying temperature and humidity conditions; and in chemical stability, SPBI demonstrates remarkable resilience in strong acidic and oxidizing environments, making it suitable for a wide range of fuel cell and flow battery systems. Currently, Zhongke Jinding offers a series of SPBI membranes with sulfonation degrees ranging from 40% to 100%, achieving proton conductivities of 80–150 mS/cm. These membranes can also be blended with materials such as SPEEK to further optimize overall performance and address customers’ customized application requirements.

 

Schematic of the SPBI molecular structure

• Sulfonation degree: 40–100%, customizable and adjustable to meet specific requirements.
• Proton conductivity (mS/cm): 80–150, maintaining excellent performance even under low-temperature and low-humidity conditions.
• Thermal decomposition temperature: >450°C, stable operation under a nitrogen atmosphere
• Cost Advantage: 1/3, a significant reduction compared to Nafion membranes.
• Structural Design: The SPBI membrane retains the aromatic heterocyclic structure of the PBI backbone, inheriting its excellent thermal stability and mechanical strength, while the introduction of sulfonic acid groups establishes continuous hydrated proton‑transport channels.
• Efficient transmission: The sulfonic acid groups establish continuous hydrated proton‑transport pathways within the membrane, significantly enhancing proton conductivity and ensuring robust performance even under low‑temperature, low‑humidity conditions.
• Stable and reliable: The SPBI membrane exhibits excellent stability in strong acid and oxidizing environments, making it suitable for a wide range of fuel cell and flow battery systems, with a cycle life exceeding 1,000 cycles.

 

SPBI vs Perfluorosulfonic Acid Membrane (Nafion): A Core Comparison

Comparison dimension	SPBI membrane	Nafion membrane	Advantage Determination
Material structure	Non-fluorinated heteroaromatic ring	Perfluorosulfonic acid	Lower cost
Proton conductivity	80-150 mS/cm	100-150 mS/cm	Quite
Sulfonation degree is adjustable.	40%-100% adjustable	Fixed EW value	High flexibility
Chemical stability	Stable in strong acids/oxidizing agents	Stable in strong acids/oxidizing agents	Quite
Thermal stability	>450°C	~200°C	SPBI is better
Applicable System	Fuel cell + flow battery	Fuel cells as the primary source	SPBI is broader
Preparation cost	Lower	High (fluorination process is complex)	SPBI is better

 

Product Series

Zhongke Jinding offers a series of SPBI membrane products with sulfonation degrees ranging from 40% to 100%, and can be blended and processed with materials such as SPEEK to further optimize overall performance and meet customers’ customized application requirements. Custom thicknesses are available across a range of 20 μm to 100 μm.

 

Application areas

It is widely used in proton exchange membrane fuel cells (PEMFCs), high-temperature PEM fuel cells (HT‑PEMFCs), all-vanadium redox flow batteries (VRFBs), and various electrochemical energy storage and conversion systems.

 

Zhongke Jinding—dedicated to the research and development of advanced membrane materials, driving high-quality growth in the hydrogen energy industry.