Reusable Lignin-Derived Free-Standing Carbon Nanofiber Sulfur Hosts via Carbonization Engineering for Sustainable Lithium-Sulfur Batteries.

As an abundant bio-based resource, lignin can be converted to functional carbon materials, thereby providing a sustainable pathway toward free-standing sulfur cathode design. However, rational carbonization engineering remains essential for optimizing sulfur utilization and polysulfide conversion behavior in lithium-sulfur batteries. In this work, lignin valorization and free-standing electrode design are integrated through electrospinning-assisted fabrication of nanofibers, followed by high temperature carbonization to produce flexible and reusable sulfur hosts. The interconnected fibrous architecture facilitates homogeneous sulfur distribution, while promoting polysulfide confinement and electrochemical stability under high sulfur loading and lean electrolyte. At a sulfur loading of 3.3 mg cm-2, the electrode affords a high initial capacity of 1300 mAh g-1. At an electrolyte content of 5.5 µLE mgS -1, the coin cells are shown to cycle steadily with capacity retentions of 82.9% after 100 cycles at 0.2 C. Furthermore, the reusability of these electrodes is confirmed via successful recovery, with the recovered electrode demonstrating stable cycling at 1 C, while retaining 79.3% of its initial capacity after 150 cycles. This research thus confirms the potential of lignin-derived, green, and cost-effective approach of synthesizing free-standing electrodes as efficient sulfur host materials with reliable and steady battery cycling performance.