NiMoO₄ Nanosheets Anchored on NS Doped Carbon Clothes with Hierarchical Structure as a Bidirectional Catalyst toward Accelerating Polysulfides Conversion for LiS Battery

Abstract

The serious shuttle effect, sluggish reduction kinetics of polysulfides and the difficult oxidation reaction of Li 2 S have hindered LiS battery practical application. Herein, a 3D hierarchical structure composed of NiMoO 4 nanosheets in situ anchored on NS doped carbon clothes (NiMoO 4 @NSCC) as the free-standing host is creatively designed and constructed for LiS battery. Dual transitional metal oxide (NiMoO 4 ) increases the electrons density near the Fermi level due to the contribution of the incorporating molybdenum (Mo), leading to the smaller bandgap, and thus stronger metallic properties compared with NiO. Furthermore, as a bidirectional catalyst, NiMoO 4 is proposed to facilitate reductions of polysulfides through lengthening the SS bond distance of Li 2 S 4 and reducing the free energy of polysulfides conversion, meanwhile promote critical oxidation of insulative discharge product (Li 2 S) via lengthening LiS bond distance of Li 2 S and decreasing Li 2 S decomposition barrier. Therefore, after loading sulfur (2 mg cm −2 ), NiMoO 4 @NSCC/S as the self-supporting cathode for the LiS battery exhibits impressive long cycle stability. This study proposes a concept of a bidirectional catalyst with dual metal oxides, which would supply a novel vision to construct the high-performance LiS battery.

Gd 2 O 3 nanoparticles modified wave‐like carbon host derived from soybean residue as cathodes in l ithium–sulfur batteries

“…Among them, the first strong peak at 169.1 eV is attributed to the S–O/S═O bond. The other two peaks at 164.4 and 165.9 eV are attributed to the characteristic S 2p1/2 and S 2p3/2 electronic shells of S8 26 . The S–O bond implies the chemical adsorption capacity between Gd 2 O 3 and S or LiPSs.…”

“…The other two peaks at 164.4 and 165.9 eV are attributed to the characteristic S 2p1/2 and S 2p3/2 electronic shells of S8. 26 The S-O bond implies the chemical adsorption capacity between Gd 2 O 3 and S or LiPSs. The successful loading of Gd 2 O 3 in ASC can be further confirmed by Gd 4d3/2 and Gd 4d5/2 peaks located at 147.9 and 143.6 eV in Figure 5g.…”

Ionic‐Liquid‐Assisted Synthesis of N, F, and B Co‐Doped CoFe2O4−x on Multiwalled Carbon Nanotubes with Enriched Oxygen Vacancies for Li–S Batteries

“…Notably, for the last two steps, the values of Δ G for CoFe 2 O 4− x were considerably smaller than those of CoFe 2 O 4 , illustrating that the sulfur reduction is thermodynamically more favorable on NFBCoFe 2 O 4− x @MWCNTs than on CoFe 2 O 4 @MWCNTs. [ 57 ] Figure 8c shows the visual simulation of the charge transfer between Li 2 S n ( n = 8, 6, 4, 2, and 1) and NFBCoFe 2 O 4− x @MWCNTs based on the charge density difference plots. The charge transfer density for the NFBCoFe 2 O 4− x @MWCNTs demonstrates that the polysulfides was easily bonded with NFBCoFe 2 O 4− x @MWCNTs, which enhanced the interaction between NFBCoFe 2 O 4− x @MWCNTs and polysulfides to effectively suppress the “shuttle effect.” Based on the results above, we vividly summarized the mechanism to explain the improved electrochemical performance using NFBCoFe 2 O 4− x @MWCNTs, as shown in Figure 8d,e.…”

Catalytic Boosting Bidirectional Polysulfide Redox using Co0.85Se/C Hollow Structure for High‐Performance Lithium‐Sulfur Batteries

“…If not solved, the adsorbed polysulfides will accumulate and form a thick passivation layer, thereby rendering reduced sulfur utilization and short cycle life. [26,27] To address this issue, construction of bifunctional separators with both good absorption and high electrocatalytic conversion of polysulfides is urgent and necessary. In this regard, a vast variety of materials, such as transition metal carbides/sulfides, have been reported as great electrocatalysts to accelerating the polysulfides redox kinetics, and accordingly, the electrochemical performance of LSBs has been improved substantially.…”