Embedding Fe₃C and Fe₃N on a Nitrogen-Doped Carbon Nanotube as a Catalytic and Anchoring Center for a High-Areal-Capacity Li–S Battery

Abstract

The biggest obstacles of putting lithium−sulfur batteries into practice are the sluggish redox kinetics of polysulfides and serious "shuttle effect" under high sulfur mass loading and lean-electrolyte conditions. Herein, Fe 3 C/Fe 3 N@nitrogen-doped carbon nanotubes (NCNTs) as multifunctional sulfur hosts are designed to realize high-areal-capacity Li−S batteries. The Fe 3 N and Fe 3 C particles attached to NCNT can promote the conversion of polysulfides. Besides, NCNT can not only enhance the chemisorption of polysulfides but also increase the special surface area and electrical conductivity by constructing a three-dimensional skeleton network. Integrating the merits of high electrical conductivity, high catalytic activity, and strong chemical binding interaction with lithium polysulfides (LiPSs) to achieve in situ anchoring conversion, the Fe 3 C/Fe 3 N@NCNT multifunctional hosts realize high sulfur mass loading and accelerate redox kinetics. The novel Fe 3 C/Fe 3 N@NCNT/S composite cathode exhibits steady cycle ability and a high areal capacity of 9.10 mAh cm −2 with a sulfur loading of 13.12 mg cm −2 at 2.20 mA cm −2 after 50 cycles.

Iron‐doped Ag/Ni2(CO3)(OH)2 hierarchical microtubes for highly efficient water oxidation

“…Moreover, in the Fe 2p 3/2 region (Figure 3F), peaks at 711.3 and 714.6 eV are attributed to carbonates and Fe–OH, respectively, and the peak at 718.3 eV is the satellite peak. In the Fe 2p 1/2 region, 722.8 eV is assigned to Fe–CO 3 2− and a peak appears near 725.3 eV for Fe–OH, with a satellite peak appearing near 733.6 eV, confirming that the Fe species were successfully doped into Ag/NiHC HMTs 12,25,39 …”

“…In the Fe 2p 1/2 region, 722.8 eV is assigned to Fe-CO 3 2− and a peak appears near 725.3 eV for Fe-OH, with a satellite peak appearing near 733.6 eV, confirming that the Fe species were successfully doped into Ag/NiHC HMTs. 12,25,39 To elucidate the advantages of a hierarchical hollow structure and Fe doping, the OER activity of electrocatalysts was evaluated in a 1.0 M KOH electrolyte at room temperature. As shown in the inset of Figure 4A, a positive shift of 18 mV was observed for the Ni 2+ /Ni 3+ oxidation peak of Ag/NiFeHC HMTs, indicating that the doped Fe can modulate the electronic structure of Ni ions by inducing a chemical environment, 28 which is consistent with the XPS results.…”

An Aqueous Binder for High-Areal-Capacity Fe3O4-Based Anodes in Lithium-Ion Batteries

“…Figure c is the full spectra of the Fe 3 O 4 @C composite, revealing the coexistence of Fe, O, and C elements. Figure d shows that the Fe 2p XPS spectra, typical spectra of Fe 3 O 4 , consists of Fe 2p 1/2 (724.9 eV) and Fe 2p 3/2 states (711.3 eV). − The peaks at 531.9 and 533.4 eV in the spectrum of O 1s (Figure e) may be ascribed to Fe–O–C and C–O . The peaks of C 1s spectrum can be decomposed at 284.6 eV (C–C and C–H bonds), 285.8 eV (O–C–O species), and 288.4 eV (carbonate species). − …”

Synergistic Effect between Monodisperse Fe3O4 Nanoparticles and Nitrogen-Doped Carbon Nanosheets to Promote Polysulfide Conversion in Lithium–Sulfur Batteries

“…With increasing energy shortages and global warming, more attention is being paid to energy storage systems for renewable and clean energy sources, such as secondary batteries of lithium-ion, lithium–sulfur, zinc-ion, and sodium-ion types. , Among them, ultra-high theoretical energy density reaching 2600 W h kg –1 , environmental benignness, and low cost make lithium–sulfur batteries (LSBs) the most promising next-generation energy storage technology, which has attracted widespread research attention. − However, commercialization of LSBs is significantly impeded by inherent insulating properties of sulfur and lithium sulfide, which reduce electron- and ion-transfer rates. Furthermore, the “shuttle effect” and slow conversion kinetics of lithium polysulfides (LiPSs), as well as volume change of sulfur during repeated charge/discharge operation, lowers the cycling life and stability of these batteries. − …”