Novel sustainable nitrogen, iodine-dual-doped hierarchical porous activated carbon as a superior host material for high performance lithium-sulfur batteries

摘要

Lithium-sulfur (Li-S) batteries exhibit great potential for next-generation high energy density energy storage. However, the insulativity of sulfur and the "shuttle effect" of polysulfides result in low utilization efficiency of active sulfur, fast capacity decay and inferior cycling stability, which pose the key challenge to their practical applications. Herein, a N, I-dual-doped hierarchical porous activated carbon (NIWFC) is successfully prepared for advanced Li-S batteries by the simple one-pot pyrolysis and hydrothermal processes. The obtained NIWFC owns interconnected porous framework with desirable specific surface area (2088.56 m(2) g(-1)) and large volume space (1.106 cm(3) g(-1)), which can accommodate high content of active sulfur and immobilize polysulfides through physical confinement. Moreover, the existence of N and I heteroatoms could effectively strengthen the chemical adsorption to polysulfides and create more active sites to enhance sulfur utilization. Attributed to these merits, impregnating sulfur into NIWFC (NIWFC/S) as cathode of Li-S batteries achieves a high initial discharge capacity of 1284.1 mAh g(-1) at 0.1 C (remaining at 916.7 mAh g(-1) after 100 cycles) and the outstanding cycling stability with a low capacity fading rate of 0.061% per cycle over 350 cycles at 1.0 C. This work provides a facile and cost-effective strategy to design a novel sustainable N, I-dual-doped porous carbon for high performance Li-S batteries and various energy storage fields. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.