Integrated Design of MnO₂@Carbon Hollow Nanoboxes to Synergistically Encapsulate Polysulfides for Empowering Lithium Sulfur Batteries

Abstract

Lithium sulfur batteries (LSBs) with high theoretical energy density are being pursued as highly promising next-generation large-scale energy storage devices. However, its launch into practical application is still shackled by various challenges. A rational nanostructure of hollow carbon nanoboxes filled with birnessite-type manganese oxide nanosheets (MnO @HCB) as a new class of molecularly-designed physical and chemical trap for lithium polysulfides (Li S (x = 4-8)) is reported. The bifunctional, integrated, hybrid nanoboxes overcome the obstacles of low sulfur loading, poor conductivity, and redox shuttle of LSBs via effective physical confinement and chemical interaction. Benefiting from the synergistic encapsulation, the developed MnO @HCB/S hybrid nanoboxes with 67.9 wt% sulfur content deliver high specific capacity of 1042 mAh g at the current density of 1 A g with excellent Coulombic efficiency ≈100%, and retain improved reversible capacity during long term cycling at higher current densities. The developed strategy paves a new path for employing other metal oxides with unique architectures to boost the performance of LSBs.

Chemical Immobilization Effect on Lithium Polysulfides for Lithium–Sulfur Batteries

“…(ii) Sluggish kinetics—the common Li–S voltage profiles tend to show a higher polarization in the lower discharge plateau voltage due to limited kinetics for both electrons and lithium ions, which further results in a decrease in practical energy density. To improve the conductivity of the cathodes, various host materials are rationally designed for sulfur cathodes including high‐surface‐area porous carbon material, conductive polymer materials, and some other conductive semiconductive materials …”

Polysulfide Trapping in Carbon Nanofiber Cloth/S Cathode with a Bifunctional Separator for High‐Performance Li–S Batteries

“…The Mn 2p 3/2 spectrao ft he b-MnO 2 NWs could be deconvoluted into three characteristic peaks centered at 641.2, 642.1, and 643.7 eV, which were attributed to Mn 3 + ,M n 4 + ,a nd as atellite peak, re- Figure 7. [18] Conversely,t he relative peak intensity between the terminal (S T À1 )a nd bridging sulfur (S B 0 )o ft he S2ps pectra decreased dramatically,a nd the relative intensity of the sulfate peaks at 165 and 170 eV corresponding to the oxidation of Li 2 S 4 increased after the adsorption test (Figure 9c). ChemSusChem 2019ChemSusChem , 12,2447ChemSusChem -2456 www.chemsuschem.org spectively (Figure 9b).…”

Recent development of metal compound applications in lithium–sulphur batteries

“…Therefore a considerable amount of conductive additives, such as the conductive polymer or conductive carbon, should be introduced to overcome the dead active material and achieve high performances. 43,[82][83][84][85] Yu and her co-workers designed a S/Polypyrrole-MnO 2 (S/PPyMnO 2 ) ternary nanostructure as shown in Fig. 2(a).…”