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The use of inexpensive graphite oxide (GO) as a carbon source, instead of the expensive reduced graphene oxide (rGO), is essential to prepare metal oxide/rGO composites. In this work, we investigated the in situ reaction of GO and FeCl3 to produce Fe2O3/rGO composites as anode materials for high‐energy lithium‐ion batteries (LIBs). In this reaction, iron ions combined with the oxygen‐containing functional groups of GO, which subsequently grew into Fe2O3 nanoparticles, whereas the GO transformed into rGO under hydrothermal conditions. In the composite Fe2O3−rGOx samples, intergranular gaps in the Fe2O3 sub‐micron particles evidently increased the contact between the Fe2O3 active material and the electrolyte, which improved the Li‐ion conductivity and electrochemical performance of the Fe2O3−rGOx composites. The Fe2O3−rGO2 sample showed the best cyclic performance and delivered the highest capacity of all samples. The initial discharge and charge capacities of Fe2O3−rGO2 were 1086.3 and 722.4 mAh g−1, respectively. After 100 cycles, the discharge specific capacity of Fe2O3−rGO2 was 653.2 mAh g−1 and the coulombic efficiency was 98.4 %. We found that an appropriate weight ratio and composite morphology of Fe2O3−rGOx were important in influencing the electrochemical properties of the composite anode materials for high‐energy LIBs. [ABSTRACT FROM AUTHOR]

Abstract: Three‐dimensional porous SnO2/rGO xerogels with superior cycling performance in lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) are fabricated through a freeze‐drying‐assisted method. SnO2 nanoparticles (5 nm in diameter) are homogeneously attached to the surface of graphene sheets without self‐aggregation. The heterostructured SnO2/rGO xerogel possesses numerous micron‐sized pores that can efficiently buffer the volumetric change of SnO2 during the charge/discharge process and provide multidimensional channels, improving the conductivity between active materials and electrolyte. The SnO2/rGO xerogel exhibits excellent electrochemical performance, both in LIBs and SIBs, owing to its particular porous structure. For LIBs, it delivers a high initial discharge capacity of 1670.5 mAh g−1 in the first cycle and remains at 1139.4 mAh g−1 after 166 cycles at a current density of 0.1 A g−1. The SnO2/rGO xerogel also delivers a high discharge capacity of 189.4 mAh g−1 without capacity loss over 266 cycles at a current density of 0.5 A g−1 for SIBs. The SnO2/rGO xerogel can be used as an electrode material in both LIBs and SIBs, and can maintain an excellent rate performance and cyclic performance, owing to the abundant porosity and high conductivity. [ABSTRACT FROM AUTHOR]

Spinel LiMn2O4 is one of the most important cathode materials but it still suffers from rapid capacity degradation during electrochemical cycling. Beside surface coating to improve the electrochemical performances, controlling the bulk morphology of LiMn2O4 (LMO) is another effective strategy. In this work, porous LiMn2O4 microspheres composed of numerous primary nanoparticles are synthesized by micro-emulsion and co-precipitation methods. The porous structure and the primary nanoparticles size of LiMn2O4 are effected by the concentration of micro-emulsion and the precursor of Mn2+. The well-established porous LiMn2O4 microspheres with abundant ionic channels and good contact with electrolyte endow the spinel a remarkable electrochemical performance. After 300 cycles, 0.50 M-LMO sample presents excellent reversible capacity of 112.8 mAh g−1 at 0.5 C rate. After 1000 cycles, 0.50 M-LMO sample presents the highest capacity of 97.9 mAh g−1 and remains 54.2 mAh g−1 at the current rate of 10 C. The porous spherical structure of cathode materials is essential to improve the rate performance due to the good contact between the active material and electrolyte. [ABSTRACT FROM AUTHOR]

In this paper, a novel adhesive prepared by blending lithium-ion functionalized epoxy resin (ionized oligomer) with poly(vinylidenedifluoride) (PVdF) is used to fabricate the cathode electrode of LiCoO2. The properties of the blending adhesive are studied by Fourier transform infrared spectroscopy, differential scanning calorimeter, and thermogravimetric analysis, and the morphology and performance of the composite cathodes are characterized by using X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. With the blended ionized oligomer, the crystallinity behavior of PVdF is decreased effectively, which will be beneficial to the movement of conducting ions. An appropriate amount of ionized oligomer effectively improves the conductivity and charge-transfer capability of the cathode material. When the amount of ionized oligomer to the PVdF binder is 10 wt%, the LiCoO2-based composite cathode delivers the highest charge−discharge capacity (178 mAh g−1) and the capacity retention is up to 82.2 % after 100 cycles. [ABSTRACT FROM AUTHOR]

This work presents a design of sandwich MoO3/C hybrid nanostructure via calcination of the dodecylamine-intercalated layered α-MoO3, leading to the in situ production of the interlayered graphene layer. The sample with a high degree of graphitization of graphene layer and more interlayered void region exhibits the most outstanding energy storage performance. The obtained material is capable of delivering a high specific capacitance of 331 F g−1 at a current density of 1 A g−1 and retained 71% capacitance at 10 A g−1. In addition, nearly no discharge capacity decay between 1000 and 10 000 continuous charge-discharge cycles is observed at a high current density of 10 A g−1, indicating an excellent specific capacitance retention ability. The exceptional rate capability endows the electrode with a high energy density of 41.2 W h kg−1 and a high power density of 12.0 kW kg−1 simultaneously. The excellent performance is attributed to the sandwich hybrid nanostructure of MoO3/C with broad ion diffusion pathway, low charge-transfer resistance, and robust structure at high current density for long-time cycling. The present work provides an insight into the fabrication of novel electrode materials with both enhanced rate capability and cyclability for potential use in supercapacitor and other energy storage devices. [ABSTRACT FROM AUTHOR]

The article presents a study that deals with the conformation and electrochemical properties of the resulting nanocomoposites. The study proposed two mechanisms for the polymerization of monomers within the confined interlayers. It conducted analyses of thermogravimetric/differential scanning calorimetric analyses, X-ray diffraction, and Fourier transform infrared spectra which showed the parallelism or perpendicularity of the aromatic rings of the polyaniline with the organic slabs.