In Situ Fabrication of Carbon-Encapsulated Fe₇X₈ (X = S, Se) for Enhanced Sodium Storage

Abstract

Sodium-ion batteries (SIBs) have been regarded as a promising alternative to lithium-ion batteries due to the natural abundance of sodium in the earth's crust. In our work, fusiform Fe 7 X 8 @C (X = S, Se) composites were obtained via a one-step pyrolysis strategy applied to SIB anode materials. The formed carbon skeleton could prevent the Fe 7 X 8 nanoparticles from agglomeration and stabilize the interface of Fe/Na 2 X generated in the redox reactions. Fe 7 X 8 @C (X = S, Se) exhibits excellent reversible specific capacity (1005.3 mAh g −1 under 0.2 A g −1 for Fe 7 S 8 @C and 458.5 mAh g −1 under 0.5 A g −1 for Fe 7 Se 8 @C), outstanding rate performance (654.7 mAh g −1 for Fe 7 S 8 @C and 392.9 mAh g −1 for Fe 7 Se 8 @C going through 300 loops even under 2 A g −1 ), and excellent cycling properties (795.8 mAh g −1 after 50 loops under 0.2 A g −1 for Fe7S 8 @C and 399.9 mAh g −1 going through 150 loops under 0.5 A g −1 for Fe 7 Se 8 @C). The excellent electrochemical performance of Fe 7 X 8 @C composites makes them promising anode materials for SIBs.

Dual responsive wool fabric by cellulose nanowhisker reinforced shape memory polyurethane

“…Among hydrophilic materials, CNWs, which have nearly perfect crystalline structures where the cellulose chains are arranged compactly with strong hydrogen bonding interactions have attracted interest in recent years . Introduction of CNWs into a SMPU matrix would afford nanocomposites with the moisture responsive shape memory function depending on the percolation network formed by CNWs whose hydrogen bonds can be reversibly regulated by water/moisture molecules . There are few studies in literature that used CNW as a moisture switch element in film form .…”

Layered Bimetallic Metal‐Organic Material Derived Cu2SnS3/SnS2/C Composite for Anode Applications in Lithium‐Ion Batteries

“…[7a,b,8] When cycled over the full potential range (i. e. 0-3 V vs Li/Li + ), SnS 2 and Cu 2 SnS 3 undergo lithiation via similar processes, with the first reaction with Li occurring above 1.0 V. During the initial conversion stage, Li + reacts with SnS 2 forming elemental Sn and Li 2 S in a reaction which is partially irreversible (Equation 1) [9] , while in the case of Cu 2 SnS 3 formation of Cu metal also occurs (Equation 2). [7a] This results in the consumption of Li upon the formation of amorphous Li 2 S. [10] SnS 2 þ 4Li þ þ 4e À ! Sn þ 2Li 2 S ð1Þ…”

Bio-inspired electrochemical corrosion coatings derived from graphene/natural lacquer composites

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