Dual Core–Shell-Structured S@C@MnO₂ Nanocomposite for Highly Stable Lithium–Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteries have currently excited worldwide academic and industrial interest as a next-generation high-power energy storage system (EES) because of their high energy density and low cost of sulfur. However, the commercialization application is being hindered by capacity decay, mainly attributed to the polysulfide shuttle and poor conductivity of sulfur. Here, we have designed a novel dual core-shell nanostructure of S@C@MnO nanosphere hybrid as the sulfur host. The S@C@MnO nanosphere is successfully prepared using mesoporous carbon hollow spheres (MCHS) as the template and then in situ MnO growth on the surface of MCHS. In comparison with polar bare sulfur hosts materials, the as-prepared robust S@C@MnO composite cathode delivers significantly improved electrochemical performances in terms of high specific capacity (1345 mAh g at 0.1 C), remarkable rate capability (465 mA h g at 5.0 C) and excellent cycling stability (capacity decay rate of 0.052% per cycle after 1000 cycles at 3.0 C). Such a structure as cathode in Li-S batteries can not only store sulfur via inner mesoporous carbon layer and outer MnO shell, which physically/chemically confine the polysulfides shuttle effect, but also ensure overall good electrical conductivity. Therefore, these synergistic effects are achieved by unique structural characteristics of S@C@MnO nanospheres.

A Comprehensive Understanding of Lithium–Sulfur Battery Technology

“…Copyright 2018, American Chemical Society. b–d) Reproduced with permission . Copyright 2017, American Chemical Society.…”

“…A suggested way to mitigate the low electrical conductivity of both sulfur and oxides is through the adoption of S@C@MnO 2 dual core–shell nanostructures (Figure b) . Indeed, while the outer polar MnO 2 shell is capable of chemically entrapping polysulfides, the carbon interlayer can offer high conductivity for the inner sulfur active material.…”

Bi‐Metal (Zn, Mn) Metal–Organic Framework–Derived ZnMnO3 Micro‐Sheets Wrapped Uniformly with Polypyrrole Conductive Network toward High‐Performance Li‐Ion Batteries

“…Also the C 1s (Figure e) spectrum demonstrates four peaks. The one at 288.1 eV is related to C═N/C═O, and those at 286.6 and 285.4 eV are attributed to C–O and C–N, respectively, whereas the peak located at 284.5 eV is indexed as C–C/C═C bond . The spectrum of the N 1s (Figure f) can be divided into three peaks at 401.3, 400.0, and 398.4 eV, which can be attributed to NH + , –NH, and –C═N, respectively …”

Improving Polysulfides Adsorption and Redox Kinetics by the Co4N Nanoparticle/N‐Doped Carbon Composites for Lithium‐Sulfur Batteries

“…Hence, it is an effective strategy to combine functional carbon materials and metal compounds to improve the electrochemical performance of Li‐S batteries. Nevertheless, it should be emphasized that some relevant works reported that these metal compounds/carbon composites were synthesized with multiple steps, resulting in weak interaction and uneven dispersion of the metal compounds nanoparticles on the carbon surface without complete contact and protection, thus, leading to limited improvements in electrochemical performance. Besides, inclusion of inactive components like binder (PVDF) and conductivity addition (carbon black) and toxic solvent used in the slurry‐coating procedure limit the application in practical.…”