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Hybrid materials of CoFeO nanoparticles anchored on graphene prepared by a facile hydrothermal process was developed to be anode material for sodium-ion battery. The hybrid nano-structure of CoFeO/graphene not only could be useful to buffer electrode volume accompanying with Na insertion-extraction, but also could be beneficial to improve electrode electric conductivity and further keep graphene sheet separated to improve ion diffusion rate. Electrochemical measurements showed that the hybrid material anode displayed an excellent performance with a large reversible capacity of 330 mAh g after 75 cycle times and a satisfactory rate capability of 170 mAh g at 1 A g. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have attracted lots of significant interests, arising from in regard to the development of developing a low-cost energy storage system for renewable energy. Antimony-based materials with that have high theoretical storage capacities of Na + have become one of the most focused SIB anode materials. Among of which, Sb 2 O 4 has a higher and thus superior Na + storage capacity of 1227 mAh g −1 compared to other antinomy-based materials. In this work, one simple solvothermal process has been developed to prepare Sb 2 O 4 /reduced graphene oxide (Sb 2 O 4 /RGO) composites with a nanostructure of Sb 2 O 4 nanorods anchored on RGO. Sb 2 O 4 /RGO shows an obviously enhanced electrochemical performance with an initial Na + storage capacity of 842 ± 5 mAh g −1 , a rechargeable capacity of 551 ± 5 mAh g −1 at 50 mA g −1 after 100 cycles and an excellent rate performance of 401 ± 5 mAh g −1 at 1 A g −1 . [ABSTRACT FROM AUTHOR]

The small-size SnO 2 particles uniformly dispersed on the nitrogen doping graphene nanocomposites (SnO 2 -N-GNS) have been successfully synthesized by a mild hydrothermal method with the precursors of graphene oxide, urea and SnCl 4 . 5H 2 O. The phase (XRD, EDX and XPS) and morphology (SEM, TEM) analysis further confirm the obtained products. When the composite served as anode material in sodium ion batteries (SIBs), it delivers superior sodium storage performance with reversible discharge capacity of 294.4 mAh g −1 at a current density of 50 mA g −1 in the voltage range from 0.01–3 V after 50 discharge/charge cycles, which is much higher than that of SnO 2 -GNS (182.9 mAh g −1 ) and N-GNS (114.9 mAh g −1 ). Besides, the SnO 2 -N-GNS electrode also exhibits admirable rate stability with the discharge capacity of 206 mAh g −1 even at 800 mA g −1 . More importantly, the SnO 2 -N-GNS shows lower internal resistance and larger sodium-ion diffusion coefficient. These enhanced electrochemical performances of SnO 2 -N-GNS are due to the N-doping defects and the homogeneous dispersion of SnO 2 particles. [ABSTRACT FROM AUTHOR]

Nanocomposites of porous graphene anchored with Sb/SbO x nanoparticles were synthesized through a two-step wet chemical process. SbO x /graphene was initially prepared by refluxing SbCl 3 and graphene oxide in benzyl alcohol. Subsequently, the SbO x nanoparticles were partially reduced by NaBH 4 . The nanocomposites exhibited an enhanced performance for sodium-ion battery with a stable sodium-ion storage capacity of 311.6 mAh g −1 at 50 mA g −1 after 100 cycles and a rate capability of 205.6 mAh g −1 at 800 mA g −1 . Reduction of SbO x by adding moderate amount of NaBH 4 was conducive in improving the nanocomposite's electrochemical performance. The sodium-ion storage capacity of Sb/SbO x /graphene material was 1.4 times higher than that of SbO x /graphene without NaBH 4 and 6.2 times higher than that of Sb/graphene with excessive amount of NaBH 4 . [ABSTRACT FROM AUTHOR]