Prussian Blue Analogue-Derived Fe-Doped CoS2 Nanoparticles Confined in Bayberry-like N-Doped Carbon Spheres as Anodes for Sodium-Ion Batteries

Abstract

Obvious volume change and the dissolution of polysulfide as well as sluggish kinetics are serious issues for the development of high performance metal sulfide anodes for sodium-ion batteries (SIBs), which usually result in fast capacity fading during continuous sodiation and desodiation processes. In this work, by utilizing a Prussian blue analogue as functional precursors, small Fe-doped CoS2 nanoparticles spatially confined in N-doped carbon spheres with rich porosity were synthesized through facile successive precipitation, carbonization, and sulfurization processes, leading to the formation of bayberry-like Fe-doped CoS2/N-doped carbon spheres (Fe-CoS2/NC). By introducing a suitable amount of FeCl3 in the starting materials, the optimal Fe-CoS2/NC hybrid spheres with the designed composition and pore structure exhibited superior cycling stability (621 mA h g−1 after 400 cycles at 1 A g−1) and improved the rate capability (493 mA h g−1 at 5 A g−1). This work provides a new avenue for the rational design and synthesis of high performance metal sulfide-based anode materials toward SIBs.

Achieving High-Rate and Stable Sodium-Ion Storage by Constructing Okra-Like NiS2/FeS2@Multichannel Carbon Nanofibers

“…The cycling performance at 1 A g –1 is depicted in Figure D, delivering a reversible capacity of 256 mA h g –1 after 100 cycles with an 82.2% capacity retention. According to Figure E, it shows excellent rate capabilities of 327, 293, 268, 238, and 160 mA h g –1 at stepwise current densities of 0.2, 0.5, 1, 2, and 5 A g –1 , respectively, which are superior to those of MnS/FeS 2 @CNFs//NVP/C, CoS/Co 9 S 8 @NC//NVP@C, FeS/NiS@NCS//C-NVPF, NiS-FeS@NC//NVP@C, and Fe-CoS 2 /NC//NVP (Figure F). In addition, compared with other full cells, such as NTP@rGO//NVP/C, CuO-P//NVPOF, FeS 2‑x Se x //NVP, and CNT//NVP, the NiS 2 /FeS 2 @MCNFs//NVP full cell delivers a high energy density of 109.1 W h kg –1 at a power density of 63.4 W kg –1 (Figure S12), demonstrating the promising feasibility of NiS 2 /FeS 2 @MCNFs as anode for application in SIBs.…”

Prussian Blue Analogues Derived Heterostructured CoS2/FeS2 Particles Anchored on Carbon Nanosheets as Anodes for Boosted Sodium Storage Properties

“…As shown in Figure 5A, the CV curves present quite similar shapes with scan rates varying from 0.2 to 1 mV s À 1 , reflecting the limited polarization of the CoS 2 /FeS 2 /C electrode. [56] For the electrode, the detailed charge storage mechanism of capacitive or diffusion controlled processes can be analyzed from the following equation: [57] i ¼ an b where i and v represent the peak current and scan rate, while a and b are two constants. As depicted in Figure 5B, by plotting the log(i) versus log(v), the b values are estimated to be 1.28, 1.23, 1.25 and 1.05 for the selected redox peaks in Figure 5A, from which we can deduce that the charge storage mechanism of CoS 2 /FeS 2 /C is mainly dominated by the capacitive effect.…”