Defect-Rich Amorphous Iron-Based Oxide/Graphene Hybrid-Modified Separator toward the Efficient Capture and Catalysis of Polysulfides

Abstract

The sluggish sulfur reduction reaction, severe shuttle effect, and poor conductivity of sulfur species are three main problems in lithium−sulfur (Li− S) batteries. Functional materials with a strong affinity and catalytic effect toward polysulfides play a key role in addressing these issues. Herein, we report a defectrich amorphous a-Fe 3 O 4−x /GO material with a nanocube-interlocked structure as an adsorber as well as an electrocatalyst for the Li−S battery. The composition and defect structure of the material are determined by X-ray diffraction, highresolution transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy measurements. The distinctive open framework architecture of the as-engineered composite inherited from the metal−organic framework precursor ensures the stability and activity of the catalyst during extended cycles. The oxygen defects in the amorphous structure are capable of absorbing polysulfides and similarly work as catalytic centers to boost polysulfide conversion. Taking advantage of a-Fe 3 O 4−x /GO on the separator surface, the Li−S battery shows a capacity over 610 mA h g −1 at 1 C and a low decay rate of 0.12% per cycle over 500 cycles and superior rate capability. The functional material made via the low-cost synthesis process provides a potential solution for advanced Li−S batteries.

Rational design and low-cost fabrication of multifunctional separators enabling high sulfur utilization in long-life lithium-sulfur batteries

“…It should be noted that the battery with the p-Fe 3 O 4 -NSs-PP separator exhibits distinctly positive shift for two cathodic peaks (peaks A and B) and negative shift for the anodic peak of 878 mAh g −1 at a higher current rate of 2 C. When the current rate returns to 0.2 C, the p-Fe 3 O 4 -NSs-based battery retrieves a high capacity of 1134 mAh g −1 , showing its outstanding reversibility. Such an admirable rate performance is impressive in comparison with other previously reported separators (figure 6(f)) [49,[53][54][55][56][57][58][59][60][61][62]. In contrast, those Li-S batteries based on the PP separator and CB-based separator deliver much lower discharge capacities at various current rates, especially in the case of high-current operation.…”

Polyoxometalate-derived bimetallic catalysts for the nitrogen reduction reaction

“…2b, the Fe fine scan spectrum can be split into Fe 2p 3/2 , Fe 2p 1/2 , and satellite peaks, wherein, the two peaks at 711.1 and 724.2 eV can be ascribed to Fe 2+ 2p 3/2 and Fe 2+ 2p 1/2 respectively, and the other two peaks at 713.7 and 726.5 eV can be assigned to Fe 3+ 2p 3/2 and Fe 3+ 2p 1/2 respectively. 45,46 As shown in Fig. 2c, the Bi 4f fine spectrum located at 165.2 and 159.9 eV can be attributed to Bi 4f 5/2 and Bi 4f 7/2 of BiClO respectively.…”

Phosphorization-Introduced Defect-Rich Phosphorus-Doped Co3O4 with Propelling Adsorption–Catalysis Transformation of Polysulfide

“…When we focus on the crystal microstructure, P-Co 3 O 4 /NCNT in Figure c showcases an interplanar distance of 0.20 and 0.24 nm, corresponding to the (400) and (311) planes of Co 3 O 4 , respectively. Notably, abundant atom vacancies and dislocations are observed on the yellow circles Figure , in contrast with Co 3 O 4 /NCNT before phosphorization in Figure S2, which would change the local electron structure and intensify the electrocatalytic activity of the amorphous microarea. , Unexpectedly, we capture the typical one-dimensional defect of the distinct crystal interface between Co 3 O 4 and metallic Co as marked with yellow line in Figure d, where the existence of an outer Co is possible due to the strong reducibility of PH 3 released by the thermal decomposition of NaH 2 PO 2 ·H 2 O . X-ray diffraction (XRD) is used to uncover and compare the chemical constituent.…”