Amidation‐Dominated Re‐Assembly Strategy for Single‐Atom Design/Nano‐Engineering: Constructing Ni/S/C Nanotubes with Fast and Stable K‐Storage

Abstract

An amidation‐dominated re‐assembly strategy is developed to prepare uniform single atom Ni/S/C nanotubes. In this re‐assembly process, a single‐atom design and nano‐structured engineering are realized simultaneously. Both the NiO5 single‐atom active centers and nanotube framework endow the Ni/S/C ternary composite with accelerated reaction kinetics for potassium‐ion storage. Theoretical calculations and electrochemical studies prove that the atomically dispersed Ni could enhance the convention kinetics and decrease the decomposition energy barrier of the chemically‐absorbed small‐molecule sulfur in Ni/S/C nanotubes, thus lowering the electrode reaction overpotential and resistance remarkably. The mechanically stable nanotube framework could well accommodate the volume variation during potassiation/depotassiation process. As a result, a high K‐storage capacity of 608 mAh g−1 at 100 mA g−1 and stable cycling capacity of 330.6 mAh g−1 at 1000 mA g−1 after 500 cycles are achieved.

Single metal atoms catalysts—Promising candidates for next generation energy storage and conversion devices

“…A high reversible capacity of 608 mAh/g at 0.1 A/g and an outstanding cyclability with the capacity of 330.6 mAh/g remained at 1 A/g even after 500 cycles were recoreded. 327 The following aspects explained these high performances: (i) The special porous nanotube-like structure, which shortened the K ions diffusion path and strengthened the structural stability to resist volume change, thus leading to excellent rate capability and cyclic capability; (ii) The highly active sulfur species, elevating the high reversible capacity; (iii) The atomically dispersed Ni sites, which not only accelerated the conversion kinetics of potassium sulfate, but also lowered the decomposition energy barriers, thus greatly optimizing the K-ion storage behavior. Besides, Shi et al illustrated that Ti SAs stabilized on reduced graphene oxide (Ti-RGO) manifested high activity for tri-iodide reduction reaction (T-IRR).…”