Facile Fabrication of Honeycomb-like Carbon Network-Encapsulated Fe/Fe₃C/Fe₃O₄ with Enhanced Li-Storage Performance

Abstract

Three-dimensional honeycomb-like carbon network-encapsulated Fe/Fe3C/Fe3O4 composites are constructed via a facile pyrolysis of ferrite nitrate–poly­(vinyl pyrrolidone) precursors. The nanostructures of the composites form in terms of the iron catalysis in the pyrolysis process, which greatly depends on the reaction temperature and contents of raw materials. The Fe/Fe3C/Fe3O4/C composite obtained at 700 °C possesses a high surface area, outstanding structural stability, and fast electron/Li ion transportability. As the anode for lithium-ion batteries, it displays a high specific capacity (1295 mAh g–1 at 0.2 A g–1), long cycling stability, and fast kinetics (345 mAh g–1 after 500 cycles at 5 A g–1). Besides the nanostructures, the marriage of different components also contributes to the superior electrochemical performance. The integral carbon matrix supplies a fast electron/Li transportation pathway. Fe/Fe3C acts as an electrocatalyst in the electrode, which may bring extra capacity. The satisfied performance and facile fabrication with low cost make it a competitive material in practical applications.

Rational Design of Unique ZnO/ZnS@N-C Heterostructures for High-Performance Lithium-Ion Batteries

“…The electrochemical impedance spectroscopy (EIS) spectra of freshly prepared ZnO@N-C/CNTs, pure ZnS/CNTs, and ZnO/ZnS@N-C/CNTs electrodes are shown in Figure S3. The semicircle in the high-frequency region corresponds to the charge-transfer resistance ( R ct ) on the interface between the electrolyte and the electrode, while the sloping line at low frequency is related to the lithium ion diffusion process in the electrode. , After fitting according to the equivalent electrical circuit, the ZnO/ZnS@N-C/CNTs-0.6 electrode was found to have a small R ct of 70.57 Ω before cycling (Table S4), which is due to the high conductivity of CNTs and the carbon coating layer. The morphology of the ZnO/ZnS@N-C/CNTs-0.6 electrode after 200 cycles at 100 mA g –1 was characterized by SEM and TEM.…”

Self-standing heterostructured NiCx-NiFe-NC/biochar as a highly efficient cathode for lithium–oxygen batteries

“…Compared to the Fe 2p XPS spectrum of NiFe-PBA/PP-700 ( Figure 4d), and apart from the peaks related to Fe 2p 1/2 and Fe 2p 3/2 of Fe 2+ and Fe 3+ , respectively, a new peak at 708.2 eV was observed in the Fe 2p XPS spectrum of NiFe-PBA/PP-900. This new peak at 708.2 eV was indexed to the Fe 2p 3/2 of iron carbide [50]. Figure 4 indicates that nickel carbide was formed on NiFe-PBA/PP when it was heated to 900 °C.…”

Achieving Fast and Stable Lithium/Potassium Storage by In Situ Decorating FeSe2 Nanodots into Three-Dimensional Hierarchical Porous Carbon Networks

“…In particular, three-dimensional (3D) porous carbon materials emerged as an ideal choice for service. 39,40 Apart from the superior structural robustness, the 3D architecture offers a well-integrated network for fast electron transportation, and the abundant pores also provide open channels for electrolyte infiltration to facilitate electrode/ electrolyte contact.…”

“…To address these issues, an effective strategy is to introduce suitable carbon host materials, including hollow carbon spheres, graphene nanosheets, and carbon nanofibers to provide robust support for nanostructures. In particular, three-dimensional (3D) porous carbon materials emerged as an ideal choice for service. , Apart from the superior structural robustness, the 3D architecture offers a well-integrated network for fast electron transportation, and the abundant pores also provide open channels for electrolyte infiltration to facilitate electrode/electrolyte contact.…”