Necklace-like Fe3O4 nanoparticle beads on carbon nanotube threads for microwave absorption and supercapacitors

Carbon-incorporated Fe3O4 nanoflakes: high-performance faradaic materials for hybrid capacitive deionization and supercapacitors

“…1,2 As a result, a series of Fe 3 O 4 -based materials have been explored in electrochemical applications, including electrocatalysis, batteries, supercapacitors, capacitive deionization (CDI), etc. [3][4][5][6][7] Generally, a simple chemical co-precipitation reaction of a Fe 2+ /Fe 3+ mixture in a basic medium can easily achieve the mass production of Fe 3 O 4 materials, 8 but it usually produces bulk Fe 3 O 4 with medium performance. Obstacles to the high electrochemical performance of Fe 3 O 4 materials must be overcome, including poor electrical conductivity, aggregation tende ncy, and slow ion diffusion characteristics; 9,10 however, in reality, there are still many challenges.…”

Metal/N-Doped Carbon Nanoparticles Derived from Metal–Organic Frameworks for Electromagnetic Wave Absorption

“…However, it is still a huge challenge to explore novel EMW absorption materials that simultaneously meet the requirements of strong absorption, wide effective absorption bandwidth (EAB), thin matching thickness, and low density. To address these issues, various EMW absorption materials have been extensively excavated. − Among them, composites with magnetic and dielectric components have attracted much attention due to their good magnetic loss, dielectric loss, and impedance matching. − Nevertheless, some challenges remain, such as insufficient effective absorption capacity in S band and C band. In addition, the matching thickness is relatively thick, and it is still a great challenge to realize ultrathin matching thickness (below 1.6 mm).…”

Coupling between the 2D “Ligand” and 2D “Host” and Their Assembled Hierarchical Heterostructures for Electromagnetic Wave Absorption

“…Then, the imaginary and real parts of the complex permittivity (ε r = ε′ – j ε″) and complex permeability (μ r = μ′ – j μ″) of the ring were measured in the frequency range of 2–18 GHz using a vector network analyzer (Agilent E5071C). Finally, according to the transmission line theory, the reflection loss ( R L ) of the sample was calculated by the following equations , Here, Z 0 and Z in are the free-space impedance and input impedance, respectively. f is the frequency, c is the light velocity, and d is the matching thickness.…”