Solvothermal-assisted defect engineering in hierarchically porous carbonized wood fibers for high-performance lithium–sulfur batteries†

The pursuit of carbon neutrality and reduced carbon dioxide emissions has necessitated the development of high-energy-density energy storage devices. To this end, Li–S batteries, with their exceptionally high energy density and theoretical specific capacity, have emerged as promising devices. However, the practical application of Li–S batteries is limited by the poor conductivity of sulfur and the notorious shuttle effect of lithium polysulfides (LPS). Herein, we present a scalable solvothermal-assisted carbonization strategy to engineer micro–mesoporous carbonized wood fibers (MMCWF) with precisely tailored structural defects and hierarchical porosity. Through a solvothermal treatment followed by carbonization, the WF are transformed into a nanostructured carbon material with a high specific surface area, abundant porosity, and one-dimensional hollow architecture. The as-assembled Li–S battery with sulfur-loaded MMCWF delivers an initial discharge capacity of 1389.6 mA h g⁻¹ at 0.1 C. The MMCWF/S cathode exhibits a high-rate capacity of 690.6 mA h g⁻¹ at 4.0 C, and after 800 cycles at 1.0 C, the capacity decay per cycle is only 0.05%. This innovative material design not only provides a new sulfur host for Li–S batteries but also paves the way for the development of future high-performance energy storage devices.