Ni Single Atoms on Hollow Nanosheet Assembled Carbon Flowers Optimizing Polysulfides Conversion for Li-S Batteries

The sluggish conversion kinetics and shuttling behavior of lithium polysulfides (LiPSs) seriously deteriorate the practical application of lithium-sulfur (Li-S) batteries. Herein, Ni single atoms on hollow carbon nanosheet-assembled flowers (Ni-NC) are synthesized via a facile pyrolysis-adsorption process to address these challenges. The as-designed Ni-NC with enhanced mesoporosity and accessible surface area can expose more catalytic sites and facilitate electron/ion transfer. These advantages enable the Ni-NC-modified separator to exhibit both enhanced confinement-catalysis ability and suppressed shuttling of LiPSs. Consequently, the Li-S battery with Ni-NC-modified separator shows an initial capacity of 1167 mAh g(-1) with a low capacity decay ratio (0.033% per cycle) over 700 cycles at 1 C. Even at the sulfur loading of 6.17 mg cm(-2), a high areal capacity of 5.17 mAh cm(-2) is realized at 0.1 C, together with superior cycling stability over 300 cycles. This work provides a facile catalyst design strategy for the development of high-performance Li-S batteries.