Rooting MnO2nanosheet on carbon nanoboxes as efficient catalytic host for lithium-sulfur battery

Lithium-sulfur (Li-S) battery is one of the most promising energy storage systems for its ultrahigh theoretical capacity of 2600 Wh kg(-1). However, the shuttle effect of soluble lithium polysulfides (LiPSs) leads to severe capacity decay and hinders its practical application. In this work, ultrathin polar MnO(2)nanosheets rooting on carbon nanoboxes (C NBs) with high sulfur content have been studied as efficient host for advanced Li-S battery. The carbon nanoboxes confine the active species efficiently and provide large space to relieve the volume expansion during charging/discharging process. The polar MnO(2)nanosheets have strong absorption for LiPSs and catalyze the conversion of soluble polysulfides to insoluble Li2S2/Li2S and back to sulfur. As a result, the polysulfide dissolution and shuttle effect are minimized effectively. Li-S battery assembled with S/MnO2@C NBs cathode shows superior electrochemical performance. The discharge capacity of 856 mAh g(-1)is attained after 200 cycles at 0.2 C. The capacity can also reach 720 mAh g(-1)at 2 C, which is about 2 times higher than the battery assembled with S/C NB electrode.

Automated summary

By incorporating ultrathin polar MnO(2) nanosheets into carbon nanoboxes (C NBs), this study efficiently confines the active species, significantly reduces the dissolution and shuttle effect of soluble sulfur polysulfides (LiPS), thereby improving the electrochemical performance of lithium-sulfur batteries.