Binding properties of sulfur to enable solvent-free fabrication of high-performance polymer-free sulfur-carbon positive electrodes

The development of a scalable, cost-effective and environmentally benign manufacturing of binder-free sulfur positive electrodes can make substantial advance for lithium-sulfur (Li | |S) batteries as sustainable competitors to lithium-ion systems. Here we show a solvent- and binder-free method to fabricate sulfur-carbon composite electrodes directly on aluminum foil via thermal-assisted dry pressing. A key finding is the role of sulfur as a structural binder, where its softening, distribution, and adhesion properties enable the formation of mechanically robust electrodes without polymer binders. Systematic experimental characterizations and computational modeling reveal the underlying mechanisms governing electrodes formation and electrochemical performance. The developed binder-free positive electrodes achieve a reversible capacity of 932 mAh g⁻¹ after 500 cycles at 1.0 C rate; for comparison, conventional slurry-cast positive electrodes containing 10 wt.% binder deliver lower capacity under the same electrochemical test conditions. This scalable process has the potential to reduce fabrication costs by a factor of 2.1 while eliminating hazardous solvents and binders, offering a sustainable and cost-effective approach to advancing Li | |S battery technology.