CoS₂ Nanoparticles Wrapping on Flexible Freestanding Multichannel Carbon Nanofibers with High Performance for Na-Ion Batteries

Abstract

Exploration for stable and high-powered electrode materials is significant due to the growing demand for energy storage and also challengeable to the development and application of Na-ion batteries (NIBs). Among all promising electrode materials for NIBs, transition-mental sulfides have been identified as potential candidates owing to their distinct physics-chemistry characteristics. In this work, CoS nanomaterials anchored into multichannel carbon nanofibers (MCNFs), synthesized via a facile solvothermal method with a sulfidation process, are studied as flexible free-standing electrode materials for NIBs. CoS nanoparticles uniformly distributed in the vertical and horizontal multichannel networks. Such nanoarchitecture can not only support space for volume expansion of CoS during discharge/charge process, but also facilitate ion/electron transport along the interfaces. In particular, the CoS@MCNF electrode delivers an impressively high specific capacity (537.5 mAh g at 0.1 A g), extraordinarily long-term cycling stability (315.7 mAh g at at 1 A g after 1000 cycles), and excellent rate capacity (537.5 mAh g at 0.1 A g and 201.9 mAh g at 10 A g) for sodium storage. Free-standing CoS@MCNF composites with mechanical flexibility provide a promising electrode material for high-powered NIBs and flexible cells.

Recent Advances in Nanowire‐Based, Flexible, Freestanding Electrodes for Energy Storage

“…[13,15] MOF templates, during the sintering process, can form ac ombination of macro-,m eso-,a nd micropores in the fiber. For example, CNFs consisting of parallel multichannels throughout the fiber were fabricated by using the PAN/polystyrene (PS) system, [16] andt he SnO x /C core-shell structure was obtained by using the poly(methyl methacrylate) (PMMA)/PAN precursor. For example, CNFs consisting of parallel multichannels throughout the fiber were fabricated by using the PAN/polystyrene (PS) system, [16] andt he SnO x /C core-shell structure was obtained by using the poly(methyl methacrylate) (PMMA)/PAN precursor.…”

Synthesis of CuS@CoS2 Double‐Shelled Nanoboxes with Enhanced Sodium Storage Properties

“…Thee lectrochemical performance of the CuS@CoS 2 DSNBs are investigated by assembling coin cells.F igure 5a shows the representative cyclic voltammetry (CV) curves of the CuS@CoS 2 DSNBs.I nt he first cathodic scan, as mall broad peak at 1.49 Vc orresponds to the Na + ion insertion into the CuS structure, [30,31] while the sharp reduction peak located at 1.25 V can be assigned to Na + ion insertion into CoS 2 . [32,33] Another small peak at 0.95 Vm ay be associated with the structural transformation of the Na x CuS phases. [34,35] And the peaks at 0.85 and 0.50 Va re ascribed to the conversion of Na x CoS 2 to Co and Na 2 Sa nd the formation of as olid-electrolyte interphase (SEI) film.…”

“…[32,36,38] Figure 5b displays the representative galvanostatic discharge-charge curves of the CuS@CoS 2 DSNBs at 0.1 Ag À1 .R emarkably,t he CuS@CoS 2 DSNBs deliver as table reversible capacity of about 625 mAh g À1 ,w hich is higher than those of the CoS 2 SSNBs and CuS SSNBs (Figure S18), and most CoS x -based anodes. [33,[40][41][42][43][44] Thei nitial CV and discharge-charge curves of CuS@CoS 2 DSNBs show some difference with those of subsequent cycles,w hich can be ascribed to the structural rearrangement and formation of SEI film in the initial sodiation process. [36,38,41] Ther ate performance of the CuS@CoS 2 DSNBs,C uS@CoS 2 DSNBs,CoS 2 SSNBs and CuS SSNBs is examined at various current densities.A sp resented in Figure 5c,t he average reversible capacities of CuS@CoS 2 DSNBs are 612, 570, 535, 483, 416, 360 mAh g À1 at 0.1, 0.2, 0.3, 0.5, 1, 2Ag À1 , respectively.E ven at al arge current density of 5Ag À1 ,t he CuS@CoS 2 DSNBs can also deliver ah igh capacity of 304 mAh g À1 .I ns tark contrast, the reversible capacities of the CuS-CoS 2 DSNBs and CoS 2 SSNBs decrease quickly when the current density is increased.…”

Readiness Level of Sodium‐Ion Battery Technology: A Materials Review

“…[136] Similarly, urchin-like CoSe 2 single crystals, [137] NiSe 2 nanooctahedra, [138] and CuS 2 nanodisks [139] have also been reported. [144] Benefiting from the innovative structure, CoS 2 @MCNF electrode delivered high capacity (537.5 mAh g −1 at 0.1 A g −1 ), superior rate capacity (537.5 mAh g −1 at 0.1 A g −1 and 201.9 mAh g −1 at 10 A g −1 ), and long cycle life (315.7 mAh g −1 at at 1 A g −1 after 1000 cycles). Owing to the hollow core and well separated nanosheets with maximally exposed edges, the SnS 2 tubular structures exhibited excellent electrochemical performance.…”