Electrospinning synthesis of porous carbon nanofiber supported CoSe2 nanoparticles towards enhanced sodium ion storage

Metal–organic framework-derived nitrogen-doped carbon-confined CoSe2 anchored on multiwalled carbon nanotube networks as an anode for high-rate sodium-ion batteries

“…5i), where the two overlapping semicircles and sloped line correspond to the SEI layer resistance ( R SEI ), charge-transfer resistance ( R ct ), and Warburg impedance ( Z w ), respectively. 27,29,48 The calculated results demonstrate that the total resistance ( R SEI + R ct ) of CoSe 2 @NC/MWCNTs (148.7 Ω) is lower than that of CoSe 2 @NC (446.5 Ω), confirming the enhanced electrode reaction kinetics and electron conduction. The detailed fitted data for the two samples are collected in Table S3 †.…”

“…Obviously, the trend of the GCD curves for the CoSe 2 @NC/MWCNTs electrode is always well maintained along with increasing current rates, suggesting the superior dynamic electrochemical stability. Meanwhile, the excellent rate performance of the prepared CoSe 2 @NC/MWCNTs surpasses many of the CoSe 2 -based anodes of the SIBs in the literature 18,25,27–29,56,57,59–61 (Fig. 4f and Table S2†).…”

“…During the first reduction sweep, one prominent peak centered at 0.87 V, which disappears in the subsequent cycles, refers to the formation of the solid electrolyte interphase (SEI) film. 25,27,56 With the cycle continuing, a new broad peak centered at 1.70 V could be observed during cathodic scans, resulting from the sodiation of Co. The reduction peak at 1.40 V is assigned to the formation of Na x CoSe 2 (CoSe 2 + x Na + + x e − → Na x CoSe 2 ), the other two peaks at 1.09 and 0.61 V are attributed to the generation of CoSe/Na 2 Se (Na x CoSe 2 + (2 − x ) Na + + (2 − x ) e − → CoSe + Na 2 Se) and Co/Na 2 Se (CoSe + 2Na + + 2e − → Co + Na 2 Se), respectively.…”

“…24 To overcome these above obstacles, constructing CoSe 2 /carbon (C) hybrids is a reasonable and promising approach to boost the Na-ion diffusion and storage. Carbonaceous materials, including amorphous carbon, 23,25,26 carbon nanofibers (CNFs), 27,28 graphene (GR), 29 and carbon nanotubes (CNTs), [30][31][32][33] could not only improve the electronic conductivity but also effectively buffer the volumetric expansion of CoSe 2 , achieving superior cycling stability. Among these, CNTs, as the typical representatives of one-dimensional (1D) nanomaterials, are regarded as the prospective carbon materials because of their inherent accessible surface area, excellent chemical stability, and electrical conductivity.…”

Research progress of metal selenides anode materials for sodium-ion batteries

“…CoSe2 作为斜方镁钙石相，拥有 494 mAh g -1 的 理论容量，反应机理与 FeSe2 相似。在放电过程中， 可以检测到 NaxCoSe2 以及 CoSe 的中间体， 在完全放 电的情况下，产物为 Co 和 Na2Se，充电过程中，反 应可逆 [54] ： 放电时： [55] ； (c) 鹅卵石状 CoSe2 的储钠机理示意图 [57] 。 Figure 6 (a) SEM and (b) TEM images of urchin-like CoSe2 [55] ; (c) schematic diagram of sodium storage mechanism of cobblestone-like CoSe2 [57] . 碳的引入往往可以使 CoSe2 获得更加稳定的性 能。Wang 等 [58] 报道了在超薄碳片上生长的 CoSe2 纳 米片，CoSe2 与碳片之间的强界面相互作用赋予了复 合材料快速的电子/离子传输动力学以及良好的结构 稳定性， 从而使复合材料具有优异的倍率性能以及良 好的循环稳定性， 并且在钠离子全电池中也显示出了 高容量。Li 等 [59] 图 7 (a) N-CNT/rGO/CoSe2 NF 制备流程图 [60] ；(b) CoSe2/BNG 负极的设计方案 [61] ；CoSe2@N-CF/CNTs 的 (c) SEM, (d) TEM 图 [62] ；(e) CoSe2@BCN-750 纳米管的制备流程 [64] 。 Figure 7 (a) N-CNT/rGO/CoSe2 NF preparation flow chart [60] ; (b) CoSe2/BNG anode design scheme [61] ; CoSe2@N-CF/CNTs (c) SEM, (d) TEM image [62] ; (e) Preparation process of CoSe2@BCN-750 nanotubes [64] .…”