Search

The arrival of the 5 G era has brought great benefits to our lives, but it has also brought problems such as electromagnetic radiation. Therefore, the demand for lightweight, high‐performance microwave absorbing materials with wide effective bandwidth is increasing. Herein, MIL‐53/g‐C3N4 is first synthesized from precursors of ferric chloride, terephthalic acid, and g‐C3N4, and then thermally annealed at different temperatures to generate MOF‐Fe@C nanocomposites. Heat treatment can effectively carbonize g‐C3N4 to amorphous carbon and reduce iron in MIL‐53 to magnetic Fe and Fe3O4 nanoparticles through carbon‐thermal reduction reaction. The synergistic effect of dielectric loss of amorphous carbon and magnetic losses of magnetic particles enhances attenuation and improves impedance matching, enhancing microwave absorption. The RLmin of MOF‐Fe@C(4)‐700 is as low as ‐72.78 dB at 9.44 GHz at a thickness of 3.18 mm and its effective absorption bandwidth is as broad as 4.88 GHz, covering most of X‐band frequency range. The research introduces a novel technique for synthesizing absorbers with controllable electromagnetic characteristics by incorporating g‐C3N4 as carbon sources into MOF materials. [ABSTRACT FROM AUTHOR]

Low ionic conductivity, oxidation potential, and poor lithium stability limit the applications of solid polymer electrolyte (SPE) in advanced energy storage systems. Combining functional inorganic materials and flexible polymers is crucial for achieving high ionic conductivity and exceptional rate performance in all-solid-state batteries (ASSBs). Herein, uniform boron nitride nanosphere (BNSPH) with reactive surface defects was prepared through an improved chemical vapor deposition method with high-temperature ammonia immobilization treatment and was introduced to the poly-(ethylene oxide) (PEO)-based SPE. Homogeneously dispersed nanostructures reduce the polymer's crystallinity, facilitating the movement of polymer chain segments and significantly improving the composite electrolyte's ionic conductivity. The interaction between BNSPH and the PEO chain enhances the structural stability of the composite polymer electrolyte (CPE) under high voltage, and the oxygen vacancies on the BNSPH surface immobilize TFSI–, promoting the transfer of more dissociated Li+ through the PEO chain. In addition, the excellent thermal conductivity enhances the interface stability and effectively avoids the growth of lithium dendrites. The CPE-5% exhibits an ionic conductivity of 3.86 × 10–4 S cm–1 and high voltage stability at 60 °C. Therefore, the assembled Li|CPE-5%|Li cell exhibited stable plating/stripping for 2000 h with a small polarization voltage. Furthermore, Li/LFP batteries incorporating CPE-5% exhibit remarkable rate performance (87.8 mA h g–1 at 2.0 C) and outstanding cycle stability (157.4 mA h g–1 after 150 cycles at 0.5 C and 60 °C). Furthermore, the NCM622/Li assembled with CPE-5% could achieve an excellent lifespan. This study confirms the feasibility of this application and inspire the application of defect-rich BNSPH in SPEs. [ABSTRACT FROM AUTHOR]

The two-dimensionally layered material tin disulfide (SnS2) has a large layer spacing (0.59 nm) that accelerates the diffusion of Li+ and electrons. However, the poor conductivity and huge volume expansion limit its further use. Herein, a covalently tightly assembled SnS2@NRGO hybrid nanostructure with high porosity was successfully synthesized by sacrificing PMMA template support strategies. The high porosity and pore volume of SnS2@NRGO not only increases the permeability of active material and electrolyte and improves the utilization of active material, but also provides buffer space for the huge volume expansion of ultrathin SnS2 during the charging and discharging process. In addition, the strong synergistic effect of the covalent bonding and stable hybridization nanostructure provides an efficient Li+ transport path through the 3D tightly connected NRGO network. N doping introduces a large number of defects and adds more active sites for lithium intercalation. The SnS2@NRGO-3 used as the anodes for LIBs deliver excellent rate performance (540.1 mAh g–1 at a rate of 30 A g–1) and outstanding cycle stability (1031.9 mAh g–1 after 500 cycles at 5 A g–1; the capacity degradation rate of 0.048% per cycle), which attributed to stable hybrid nanostructure and high pore volume. Therefore, the SnS2@NRGO created by us would be a very promising candidate for the future advanced high-rate long-life Li+ storage anode. [ABSTRACT FROM AUTHOR]