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

Abstract

The industrialization of lithium–sulfur (Li–S) batteries is simultaneously impeded by the shuttle effect of lithium polysulfides and dendrites growth on lithium anode. To address both issues, a novel sulfiphilic and lithiophilic interlayer of Mo2N quantum dots decorated N‐doped graphene‐nanosheet (Mo2N@NG) are presented on polypropylene separator via a facile scalable method. Benefiting from the strong chemisorption ability, eminent electrocatalysis for LiPSs, and high chemical affinity with lithium‐ion (Li+), Mo2N@NG can efficiently catalyze the rapid transformation of LiPSs and induce uniform deposition of Li+. Theoretical calculation and in situ Raman synergistically elucidate the inhibition of shuttle effect and alleviation of dendrite growth. As a result, the assembled Li–S cell with Mo2N@NG/PP separator exhibits remarkable rate performance (860.2 mA h g–1 at 4 C), good cycling stability (0.039% capacity decay per cycle after 800 cycles at 2 C), a high areal capacity of 3.89 mA h cm–2 of Li–S pouch cell (4.5 mg cm–2 and 6 µL mg–1 at 0.2 C), and steady performance in protecting the lithium anode (at 5 mA cm–2 for 1500 h). This present strategy of quantum dots in a hybrid framework has great potential to be generalized to other transition metal‐based catalysts for advanced Li–S batteries.

Recent advances in modified commercial separators for lithium–sulfur batteries

“…5d. 204 As expected, the strongest binding energies with all polysulfide forms were by pyridinic and pyrrolic nitrogen groups on the NGO. Still, the nitrogen heteroatoms usually have lower binding energies for LiPSs than metal centers like Mo.…”

“…Quantum dots are newer but promising additives that boast excellent adsorption properties with high surface area and catalytic abilities. In a recent study by Ma et al , 204 Mo 2 N quantum dots were also used to improve the Li-ion conduction of nitrogen-doped GO (NGO) by a factor of 3. While the smaller pore sizes of the NGO layer deposited on the PP separator decreased Li-ion conductivity by 56%, the addition of lithiophilic Mo 2 N supplied attractive forces that improved Li-ion conductivity by 48% more than pristine PP.…”

Metal–Organic Framework-Derived Fe-Doped Ni3Se4/NiSe2 Heterostructure-Embedded Mesoporous Tubes for Boosting Oxygen Evolution Reaction

“…In addition to that, the characteristic D and G bands of graphitic carbon have been detected in all three samples, approving the porous carbon matrix formation during the annealing process. In particular, the presence of the D band at ∼1345 cm –1 suggests the possible defects and disorders in the material, while the G band appearing at ∼1567 cm –1 signifies the in-plane C–C stretching vibrations in the graphitic network. , The Fourier transform-infrared (FT-IR) spectral data of Ni-MOF-Fe-Se-400 and NiFe 0.2 -MOF-Se-400 confirmed the presence of a metal-Se (∼703 cm –1 ) bond in the material (Figure c), in addition to the carboxylate peaks at 1635 (CO stretching ) and 1333 cm –1 (C–O stretching ), and the adsorbed water peak (broad peak at ∼3450 cm –1 ). , …”

“…In particular, the presence of the D band at ∼1345 cm −1 suggests the possible defects and disorders in the material, while the G band appearing at ∼1567 cm −1 signifies the in-plane C−C stretching vibrations in the graphitic network. 46,47 The Fourier transform-infrared (FT-IR) spectral data of Ni-MOF-Fe-Se-400 and NiFe 0.2 -MOF-Se-400 confirmed the presence of a metal-Se (∼703 cm −1 ) bond in the material (Figure 1c), 48 in addition to the carboxylate peaks at 1635 (C�O stretching ) and 1333 cm −1 (C−O stretching ), and the adsorbed water peak (broad peak at ∼3450 cm −1 ). 21,45 Afterward, in view of elucidating the specific surface area (SSA), Fe-doped mono-metallic MOF-selenides (Ni-MOF-Fe-Se-400) and the bi-metallic MOF-selenides (NiFe 0.2 -MOF-Se-400) were subjected to BET analysis.…”

Donor–Acceptor Conjugated Microporous Polymer toward Enhanced Redox Kinetics in Lithium–Sulfur Batteries

“…Due to the large contact area between PP separator and the coating layer, the CMP-B@CNT modified separator showed excellent flexibility and could be folded for many times without exfoliation. 45 Subsequently, the electrolyte contact angle was measured to examine the surface properties of the obtained separators. As shown in Figure 3d−f, the contact angles of ether-based electrolyte on the pristine PP and CMP-T@CNT modified separator were measured as 22.2°and 10.4°, respectively.…”