Sulfurized Polyacrylonitrile (SPAN) is widely regarded as one of the most promising cathode materials for next-generation Lithium-Sulfur (Li-S) batteries. Unlike traditional Li-S cathodes that rely on physical encapsulation of elemental sulfur (S8) within carbon matrices, SPAN utilizes chemical bonding to mitigate the "shuttle effect."

SPAN is synthesized by the dehydrogenative sulfurization of Polyacrylonitrile (PAN) at temperatures typically between 300°C and 450°C. During heating, PAN undergoes cyclization to form a conjugated pyridinic backbone. Simultaneously, sulfur reacts with the polymer, removing hydrogen and forming short sulfur chains (-Sn-) covalently bonded to the transformed structure. In SPAN, sulfur exists as small molecules (typically n≤3) or single atoms rather than the bulky S8 rings found in conventional cathodes.

The unique chemistry of SPAN addresses the three "Achilles' heels" of Li-S technology: (1) Elimination of Polysulfide Shuttling: Because the sulfur is chemically tethered to the polymer backbone, it does not dissolve into the electrolyte as long-chain lithium polysulfides (Li2Sn, 4 ≤ n ≤ 8). This leads to exceptional capacity retention and high coulombic efficiency. (2) Compatibility with Carbonate Electrolytes: Conventional Li-S batteries require ether-based electrolytes, which have low boiling points and poor safety profiles. SPAN is uniquely compatible with standard Li-ion carbonate electrolytes (EC/DEC), simplifying its integration into existing manufacturing lines. High Conductivity: The cyclized, conjugated backbone of SPAN is inherently semi-conductive, reducing the need for excessive conductive carbon additives compared to S8 cathodes.

Part Number	CBEBSPANI (C-BEB-SPANI)
CAS	5612-44-2
Chemical Formula/Structure	Sulfonated PANI
Appearance	Black powder
Size Distribution	D10: 2.2 um D50: 4.6 um D90: 14.8 um
Impurities	Na: <500 ppm K: <150 ppm Ca < 20 ppm
Powder Density	~1.63 g/cm3
Specific Capacity	~700 mAh/g (discharge voltage plateau: 1.7-1.8 V)
Columbic Efficiency (Frist Cycle)	99.0%
Cycling Stability	> 100 cycles
Package Size	10 g/bottle (other package sizes, such as 25 g, 50 g, and 100 g also can be supplied upon request)

Notes: Please try to store the SPAN powder in a dry place (glovebox is the best option). 

References: 

1. X. Hu, et al. Scalable SPAN Membrane Cathode with High Conductivity and Hierarchically Porous Framework for Enhanced Ion Transfer and Cycling Stability in Li–S Batteries, ACS Materials Lett. 2023, 5, 8, 2047–2057.
2. S. Tan, et al. Structural and Interphasial Stabilities of Sulfurized Polyacrylonitrile (SPAN) Cathode, ACS Energy Lett. 2023, 8, 6, 2496–2504.