Design of double-shelled NiS-FeS@NC hollow nanocubes for high-performance sodium-ion batteries

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

“…After repeated cycling at 0.2 A g –1 for 20 cycles enabling the slow activation of active materials, the electrode of NiS 2 /FeS 2 @MCNFs presents a reversible capacity of 365 mA h g –1 in the first cycle, which rapidly decays to 346 mA h g –1 in the second cycle and gradually maintains at a level of 342 mA h g –1 with a capacity retention of 93.5% after 1100 cycles. Compared with previously reported Ni-based or Fe-based anodes, ,,− NiS 2 /FeS 2 @MCNFs demonstrates superior long-term cycling performance (Table S2). Meanwhile, NiS 2 /FeS 2 @MCNFs exhibits a reasonably high ICE of 88.5%, which increases to almost 100% in the second cycle and stabilizes at this value during the subsequent cycling process, demonstrating the robust and stable structure of NiS 2 /FeS 2 @MCNFs.…”

“…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.…”

Significantly enhanced ion‐migration and sodium‐storage capability derived by strongly coupled dual interfacial engineering in heterogeneous bimetallic sulfides with densified carbon matrix

“…More interestingly, the Co 3 S 4 /NiS@N‐C electrode has a significantly better rate capability, as evidenced by its 1.2, 1.5, and 1.8 times higher reversible capacity at 30.0 A g −1 in comparison to the Co 3 S 4 /NiS, Co 3 S 4 , and NiS electrodes. Meanwhile, a comprehensive comparison of specific capacity against the current rate between Co 3 S 4 /NiS@N‐C and state‐of‐art Co 3 S 4 or NiS‐based anodes for SIBs was conducted, we can see that the Co 3 S 4 /NiS@N‐C electrode stands out on the electrochemical performance among those of SIB anodes (Figure 4D) 18,21,54,55,60–69 establishing that the self‐constructed electric field stemmed from the Co 3 S 4 /NiS heterogeneous interface together with the outer‐carbon encapsulation on the Co 3 S 4 /NiS nanosphere surface considerably enhance the rate performance reversibility and electrochemical reaction kinetics. Moreover, by graphing the connection between average charge voltage and current rate at a charge potential platform of ∼1.52 V through the GCD curves of four electrodes (Figure S12) at different rates, a comparison of structural pulverization for four electrodes at different rates was conducted.…”