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[Display omitted] · C@p-Si/ESG composite anode material with "sandwich" structure was obtained. · Electrostatic modification enhances the stability of the loading of nano-silicon. · The "sandwich" structure alleviates the volume expansion effect of silicon. · SEI film reduces the occurrence of side reactions. · C@p-Si/ESG exhibits an excellent long-term cycle stability. Silicon-based materials have a high theoretical specific capacity and a low discharge potential, whereas the significant capacity fading owing to weak conductivity and volume exfoliation effect. The co-utilization of silicon and graphite has become a feasible method for realizing high-performance lithium-ion batteries (LIBs). Herein, the C@p-Si/ESG composite anode material with "sandwich" structure was obtained by electrostatic assembly of mildly-exfoliated graphite and electrostatic modified nano silicon, and subsequent coated with amorphous carbon on the surface of the material. The carbon coating and the mildly-exfoliated graphite form a buffer space, which alleviates the volume expansion effect of silicon in the process of lithium alloying. In addition, the SEI film is generated outside the carbon layer, reducing the consumption of the electrolyte and the occurrence of side reactions. C@p-Si/ESG exhibits a high charge–discharge rate and an excellent long-term cycle stability. [ABSTRACT FROM AUTHOR]

The NaVO sample has been successfully fabricated via a simple sol-gel method adding NaCO and VO powders into distilled water with citric acid to act as a chelating reagent. X-ray diffraction with Rietveld refinement result shows that single-phase NaVO can be obtained by our method. The differences caused by different sintering temperature exist in X-ray diffraction and scanning electron microscope (SEM), showing that sintering temperature has an important influence on crystal growth and grain size stabilization. When evaluated as an anode material for lithium-ion batteries, the nanosize NaVO electrode displays a discharge and recharge capacity of 623.8 and 355.6 mAh g in the first cycle, while a reversible discharge-charge capacity of ∼250 mAh g can be retained after 30 cycles. For comparison, the electrochemical properties of microsize NaVO prepared at a higher temperature are also displayed. Furthermore, the structure change of NaVO and its Li storage mechanism upon lithiation and delithiation process are studied by ex situ XRD and TEM in below. [ABSTRACT FROM AUTHOR]

SnO 2 -based materials have been widely studied because of their high theoretical specific capacity, whereas the significant capacity fading is caused by the low reversibility conversion reaction and volume expansion. In this work, we proposed a precipitation-polymerization-thermal treatment method to construct SnO 2 -based composites by precipitation reaction of SnCl 2 with moderately exfoliated graphite (MEG), subsequent dopamine (DA) polymerization and thermal treatment to fulfill nitrogen-doped-carbon (NC) coating and part transformation of SnO 2 to Sn. Finally, we can obtain the SnO 2 /Sn/MEG@NC composites for high-performance lithium-ion batteries (LIBs). The conductive NC coating and MEG matrix have the function in facilitating electron transportation, restraining aggregation, and adapting to volume change of SnO 2 /Sn particles. Micron-sized Sn is broken during the cycles and forms nano-sized distribution with ultrafine SnO 2 , the hybrid SnO 2 /Sn allows highly effective reversibility conversion and alloying/de-alloying reactions upon cycles. As a result, the SnO 2 /Sn/MEG@NC electrode exhibits outstanding cycling stability (837.2 mAh g−1 at 1 A g−1 after 800 cycles), displaying outstanding performance for being LIBs. [ABSTRACT FROM AUTHOR]