Self‐Polymerized Disordered Carbon Enabling High Sodium Storage Performance through Expanded Interlayer Spacing by Bound Sulfur Atoms

Abstract

An effective strategy to fabricate sulfur‐doped carbon with tunable doping sites is developed using a one‐step pyrolytic technique. Applied as Na‐storage anode, this sulfur‐doped carbon exhibits high reversible capacity, excellent rate capability (330 mAh g−1 at 0.02 A g−1 and 158 mAh g−1 at 5 A g−1), as well as superior durability (159 mAh g−1 over 10000 cycles at 2 A g−1 with 95.7 % retention). Experimental characterization and theoretical calculation reveal that interlayer C−S−C bonds not only expand the d002 spacing, but also provide an alternative pathway for electron transport. This improves Na+ ion intercalation/deintercalation capability and electronic conductivity.

Investigation of N and S Co-doped Porous Carbon for Sodium-Ion Battery, Synthesized by Using Ammonium Sulphate for Simultaneous Activation and Heteroatom Doping

“…The peak shifting towards lower 2Ɵ indicates the enlarged interlayer (d 002 ) spacing, which results from the doping of nitrogen and sulphur heteroatoms. 28 As the covalent radius of S is much larger than those of C and N elements, the introduction of S increases the interlayer distance to a greater extent which is crucial in facilitating the insertion/extraction of Na + ions.…”