Facile Synthesis of Heterostructured MoS₂–MoO₃ Nanosheets with Active Electrocatalytic Sites for High-Performance Lithium–Sulfur Batteries

Abstract

In order to overcome the shuttling effect of soluble polysulfides in lithium–sulfur (Li–S) batteries, we have designed and synthesized a creative MoS2–MoO3/carbon shell (MoS2–MoO3/CS) composite by a H2O2-enabled oxidizing process under mild conditions, which is further used for separator modification. The MoS2–MoO3 heterostructures can conform to the CS morphology, forming two-dimensional nanosheets, and thus shorten the transport path of lithium ion and electrons. Based on our theoretical calculations and experiments, the heterostructures show strong surface affinity toward polysulfides and good catalytic activity to accelerate polysulfide conversion. Benefiting from the above merits, the Li–S battery with a MoS2–MoO3/CS modified separator exhibits good electrochemical performance: it delivers a high discharge capacity of 1531 mAh g–1 at 0.2 C; the initial capacity can be maintained by 92% after 600 cycles at 1 C, and the discharge capacity decay rate is only 0.0135% per cycle. Moreover, the MoS2–MoO3/CS battery still achieves good cycling stability with 78% capacity retention after 100 cycles at 0.2 C with a high sulfur loading of 5.9 mg cm–2. This work offers a facile design to construct the MoS2–MoO3 heterostructures for high-performance Li–S batteries, and may also improve one’s understanding on the heterostructure contribution during polysulfide adsorption and conversion.

Mo2N Quantum Dots Decorated N‐Doped Graphene Nanosheets as Dual‐Functional Interlayer for Dendrite‐Free and Shuttle‐Free Lithium‐Sulfur Batteries

“…[23,58] The Mo 2 N@NG electrode exhibits the maximum i 0 (1.21 × 10 -2 mA cm -2 ) in both oxidations compared with NG (4.78 × 10 -4 mA cm -2 ), showing the accelerated kinetics conversion rate on the electrode surface. [24] The chronoamperometry curves of NG and Mo 2 N@NG of Li 2 S 6 symmetric cells possess boosted current response than those cells without Li 2 S 6 , indicating that the current responses in the lithiation-delithiation reaction process rather than doublelayer capacitance (Figure 6f). [66] Moreover, the Mo 2 N@NG cell delivers the highest current response, further demonstrating the accelerated redox kinetics of LiPSs.…”

Selective Nitridation Crafted a High‐Density, Carbon‐Free Heterostructure Host with Built‐In Electric Field for Enhanced Energy Density Li–S Batteries

“…More notably, Figure 1f clearly reveals the TiO 2 @VN heterojunction, showing the multiple heterointerfaces of TiO 2 and VN crystals, such as TiO 2 (101)/VN (111) and TiO 2 (101)/VN (200). [38][39][40] High-angle annular dark-field scanning TEM (HAADF-STEM) combined with energy-dispersive Xray (EDX) elemental mapping verifies the homogeneous distribution of Ti, V, O, and N elements in the fibrous TiO 2 @VN heterostructure (Figure 1g). Figure 1h displays the FESEM images of TiO 2 @VN-S composite at different magnifications.…”

Conversion of layered materials to ultrathin amorphous nanosheets induced by ball-milling insertion and pure-water exfoliation

“…The 2D nanostructures afford the short diffusion pathway of ions, amorphous hetero-structures offer rich active sites, 54 and the heterostructured nanosheets combine the great adsorption of BN and carbon nanosheets and strong catalytic activity of MoS 2 to block the polysulfide migration and accelerate the redox kinetics of polysulfides. 55 Also, introducing amorphous nanosheets or heterostructured nanosheets into the separator contributes to the formation of more thermally conductive paths. 56 These excellent performances may be attributed to the interfacial synergetic effect.…”