Preparation of Hollow Core–Shell Fe3O4/Nitrogen-Doped Carbon Nanocomposites for Lithium-Ion Batteries

Abstract

Iron oxides are potential electrode materials for lithium-ion batteries because of their high theoretical capacities, low cost, rich resources, and their non-polluting properties. However, iron oxides demonstrate large volume expansion during the lithium intercalation process, resulting in the electrode material being crushed, which always results in poor cycle performance. In this paper, to solve the above problem, iron oxide/carbon nanocomposites with a hollow core–shell structure were designed. Firstly, an Fe2O3@polydopamine nanocomposite was prepared using an Fe2O3 nanocube and dopamine hydrochloride as precursors. Secondly, an Fe3O4@N-doped C composite was obtained by means of further carbonization treatment. Finally, Fe3O4@void@N-Doped C-x composites with core–shell structures with different void sizes were obtained by means of Fe3O4 etching. The effect of the etching time on the void size was studied. The electrochemical properties of the composites when used as lithium-ion battery materials were studied in more detail. The results showed that the sample that was obtained via etching for 5 h using 2 mol L−1 HCl solution at 30 °C demonstrated better electrochemical performance. The discharge capacity of the Fe3O4@void@N-Doped C-5 was able to reach up to 1222 mA g h−1 under 200 mA g−1 after 100 cycles.

Nano Metal–Organic Frameworks as Advanced Electrode Materials in Electrochemical Energy Storage

“…Hu and co-workers designed an iron oxide/carbon nanocomposite with a hollow core-shell structure [62] as shown in Figure 2c. Firstly, nano Fe 2 O 3 @polydopamine were prepared by using ferric trioxide nano cubes and hydrochloride as precursors.…”

Review on Recent Applications of Nitrogen‐Doped Carbon Materials in CO2 Capture and Energy Conversion and Storage

“…Wang et al [ 60 ] designed iron oxide/carbon nanocomposites with a hollow core–shell structure as an electrode for LIBs. Fe 2 O 3 @polydopamine nanocomposite was prepared using an Fe 2 O 3 nanocube and dopamine hydrochloride as precursors.…”

Metal Fluoride Cathode Materials for Lithium Rechargeable Batteries: Focus on Iron Fluorides

“…Additionally, fluorinated metal oxides (metal oxyfluorides or mixed phase metal oxides/ metal fluorides), [115] which are fluorinated by treatment with F 2 gas, have been reported to proceed by topotactic reactions, which are the chemical replacement of F atoms for O atoms in the metal oxides. [104] Zhou et al directly fluorinated iron oxide nanoparticles (n-Fe 2 O 3 and Fe 3 O 4 [116] ) using a FBR with a steady F 2 -N 2 mixture flow rate. [117] The degree of fluorination was adjusted by changing the reaction temperature, and fluorination at 175 and 225 °C generated a thin amorphous layer of oxyfluorides on the surface.…”

“…[ 104 ] Zhou et al. directly fluorinated iron oxide nanoparticles (n‐Fe 2 O 3 and Fe 3 O 4 [ 116 ] ) using a FBR with a steady F 2 ‐N 2 mixture flow rate. [ 117 ] The degree of fluorination was adjusted by changing the reaction temperature, and fluorination at 175 and 225 °C generated a thin amorphous layer of oxyfluorides on the surface.…”