<p>Although considerable advances have been made in the development of two-dimensional materials for next-generation supercapacitors, developing high-capacity electrode materials with robust cycling stability remains a key challenge, and the exploration of sulfur-based nanosheets is still at an insufficiently developed stage. Herein, layered sulfur nanosheets (S-NSs) were synthesized via a facile electrolysis method using thiourea as the sulfur source and poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) as a stabilizer. This study explored the energy storage potential of layered sulfur nanosheets (S-NSs). Owing to the excellent stability and the proposed nanosheet-like morphology that provides good ion diffusion channels for high pseudocapacitance of sulfur, the S-NSs electrode exhibits a remarkable specific capacitance of 612&#xa0;F g⁻¹ at 1&#xa0;A g⁻¹ in 0.5&#xa0;M Na₂SO₄ aqueous electrolyte. After 10,000 cycles at 5&#xa0;A g⁻¹, it retained 87.5% capacitance while the Coulombic efficiency was maintained at 90.3%. The capacitance primarily originates from surface pseudocapacitance due to redox reactions of sulfur atoms, coupled with electric double-layer contributions. This work not only confirms the great potential of S-NSs as high-performance electrode materials for supercapacitors, but also provides new insights and a material foundation for the design of next-generation energy storage devices with high energy density and long cycle life.</p>