Facile synthesis of hierarchical Na2Fe(SO4)2@rGO/C as high-voltage cathode for energy density-enhanced sodium-ion batteries

An advanced low-cost cathode composed of graphene-coated Na2.4Fe1.8(SO4)3 nanograins in a 3D graphene network for ultra-stable sodium storage

“…As shown in Fig. 1(b), XRD diffraction pattern of the NFS@rGO matches well with the alluaudite-type structure of an alluauditetype structure (C2/c), along with some poor peaks of Na 6 Fe(SO 4 ) 4 impurity [40,46]. In this lattice, octahedral Fe sites, FeO 6 , share oxygen atoms forming bi-octahedral units, Fe 2 O 10 dimers, which are sequentially bridged through SO 4 tetrahedral units firmly with corner-sharing way, forming large tunnels in the (001) direction [47].…”

“…Also similar to CV curves, the high reversibility of electrodes is revealed by the almost overlapped charge/discharge curves in subsequent cycles. The NFS@rGO exhibits an initial Coulombic efficiency of 89%, and the Coulombic efficiency in subsequent few cycles is a little low, which may result from the irreversible decomposition of electrolyte during the charge process and the formation of the cathode electrolyte interface layer [46]. The rate capability (Fig.…”

Achieving long-cycling sodium-ion full cells in ether-based electrolyte with vinylene carbonate additive

“…Up to now, almost all reported cathode materials for Na storage, such as Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ), Na 2 Fe(SO 4 ) 2 , Na 2 FePO 4 F, Na 3 V 2 (PO 4 ) 3 , Na x MnO 2 , NaNi 1/3 Fe 1/3 Mn 1/3 O 2 , Na x FeFe(CN) 6 , Na x TMO 2 , Na 3 V 2 (PO 4 ) 2 F 3 , NaVPO 4 F, Na 3 V 2 (PO 4 ) 2 O 2 F, are studied in the esterbased electrolytes owing to the higher oxidative stability [10,12,[15][16][17][18][19][20][21][22][23]. While most researches about anode materials, for example, FeS 2 , MoS 2 , CuS, CoGa 2 S 4 , Ni 3 S 4 , TiO 2 , Bi, P, hard carbon, Na, are investigated in ether-based electrolytes, especially NaCF 3 SO 3 -Diglyme (DGM), due to superior SEI layer, thereby leading to the outstanding rate property and long-term cycle stability (Tables S1 and S2) [6,[24][25][26][27][28][29][30].…”

Synthesis of Si/Fe2O3-Anchored rGO Frameworks as High-Performance Anodes for Li-Ion Batteries

“…Figures 1d and S3c display the C 1s spectra of BM-SFG and UD-SFG, respectively. The peaks at 285.3, 286.7, and 289.2 eV are in accord with C-C, C-O, and O-C=O, respectively [48,49]. Figures 1e and S3d present Fe 2p maps, showing three characteristic peaks concentrated at 711.4 eV, 725.2 eV, and 719.3 eV, relating to the Fe 2p 3/2 , Fe 2p 1/2 , and satellite peaks, respectively.…”