Two Birds with One Stone: FeS₂@C Yolk–Shell Composite for High-Performance Sodium-Ion Energy Storage and Electromagnetic Wave Absorption

Abstract

Cost-effective material with a rational design is significant for both sodium-ion batteries (SIBs) and electromagnetic wave (EMW) absorption. Herein, we report an elaborate yolk–shell FeS2@C nanocomposite as a promising material for application in both SIBs and EMW absorption. When applied as an anode material in SIBs, the yolk–shell structure not only facilitates a fast electron transport and shortens Na ion diffusion paths but also eases the huge volume change of FeS2 during repeated discharge/charge processes. The as-developed FeS2@C exhibits a high specific capacity of 616 mA h g–1 after 100 cycles at 0.1 A g–1 with excellent rate performance. Furthermore, owing to the significant cavity and interfacial effects enabled by yolk–shell structuring, the FeS2@C nanocomposite delivers excellent EMW absorption properties with a strong reflection loss (−45 dB with 1.45 mm matching thickness) and a broad 15.4 GHz bandwidth. This work inspires the development of high-performance bifunctional materials.

Carbon-Based MOF Derivatives: Emerging Efficient Electromagnetic Wave Absorption Agents

“…Thus, for carbon-based composites, the introduction of magnetic components will help to achieve a better EMW absorption performance. Magnetic NPs, as typical magnetic components, have always been widely utilized for EMW absorption [ 139 , 161 ]. In the carbon-based MOF derivatives, besides the optimized impedance matching condition, magnetic NPs in the porous carbon can also induce the magnetic loss and agitate the interfacial polarization loss.…”

Fe7Se8 encapsulated in N-doped carbon nanofibers as a stable anode material for sodium ion batteries

“…The SEM image of as-electrospun Fe(AcAc) 3 /PAN is smooth and evenly distributed nanofiber, exhibited in Figure 1a Figure S5a). As presents in Figure 3b, the Fe 2p spectrum can be divided into Fe 2+ of Fe 3+ , demonstrating the presence of Fe 2+ and Fe 3+ state in Fe 7 Se 8 -NCFs [22]. In Figure 3c, the XPS spectrum of Se 3d consists of Se 3d 3/2 (59.5 and 58.6 eV) and 3d 5/2 (56.3 and 55.7 eV) [23].…”

Non‐Flammable Liquid and Quasi‐Solid Electrolytes toward Highly‐Safe Alkali Metal‐Based Batteries

“…[ 6 ] On the other hand, Li‐ion batteries are not economically viable for large‐scale applications (e.g., grid‐connected stationary energy storage) due to the limited Li mineral reserves and their uneven distribution in the earth crust. [ 7 ] As a result, as inexpensive alternatives of Li‐ion batteries, rechargeable sodium (Na) and potassium (K) batteries have been developed owing to the rich abundance of Na and K. [ 8 ] These alkali metal‐based batteries are revolutionizing our lives as core technologies toward a rechargeable future.…”