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

Abstract

Abstract 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.