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Amorphous catalysts with abundant defects are attractive for electrocatalytic water splitting. In this work, amorphous Fe0.95S1.05 (a-FeS) nanorods are synthesized by a facile solvothermal method using octylamine solvent and employed as a low-cost and highly active electrocatalyst towards efficient hydrogen evolution reaction (HER). The capped octylamine molecules are responsible for formation of the amorphous structure. The disordered atomic arrangement with plenty of unsaturated atoms endows the a-FeS nanorods with extensive defects as exposed catalytic sites. Compared with the crystalline Fe0.95S1.05 (c-FeS) nanorods, the a-FeS nanorods exhibit a larger electrochemical active surface area and more remarkable catalytic activity. Consequently, excellent HER performance of a small Tafel slope of 43 mV dec−1, a low overpotential of 67 mV at the current density of 10 mA cm−2, and a long operation stability of 80 h is achieved for a-FeS. This work demonstrates the best catalytic activity for hydrogen generation among iron sulfide-based catalysts to date.

Three Li 4 Ti 5 O 12 /C composites (LTO/C) with diverse carbon morphologies and structures were synthesized via a simple solid-state method, along with carbon coating performed at different periods. The morphologies and structures of the coated carbon were characterized by means of electron microscopy and Raman spectroscopy. Effects of varied coated carbon on lithium storage performance, especially high rate capability of LTO/C composites were investigated. The results revealed that the porous and homogeneous carbon layer was more facile to achieve the balance between the good electron conduction and Li ion diffusion than the island-like carbon layer and the compact one, and thus the corresponding LTO/C composite exhibited more excellent electrochemical performance. At low current rate of 0.2 C, its reversible capacity was as high as 171 mAh g −1 . At 5 C, the high capacity of 150 mAh g −1 had no loss after 300 cycles. Especially at the high charge/discharge rate of 30 C, the reversible capacity still kept a high level of 82 mAh g −1 .

Sb-doped ZnO nanorod arrays were fabricated using electrochemical solution method with suitable combination of Zn(NO3)2, hexamine and SbCl3. Cyclic voltammetry was performed to determine the suitable deposition potential range. The influences of various growth parameters on the structural and optical properties of Sb-doped ZnO nanorods were studied in detail. The applied potential was found to have a great effect on the shape, the crystalline quality and the Sb doping level of the Sb-doped ZnO nanorod. Both the increase of the Zn(NO3)2 concentration and the addition of SbCl3 were found to promote the nucleation of Sb-doped ZnO. But the addition of SbCl3 can also retard subsequent nanorod growth and thus influence the nanorod diameter. To achieve the highly-textured Sb-doped ZnO nanorod arrays with a high Sb doping level, high pH values should be avoided and the substrate with an Al-doped ZnO top layer is a good choice. Based on the above investigation, the growth mechanism of the Sb-doped ZnO nanorod was also discussed. Lastly, but most importantly, these Sb-doped ZnO nanorods were proved possessing p-type conductivity.

Methyl phenyl bis-methoxydiethoxysilane (MPBMDS) was prepared and its effects were investigated as an additive in 1.0 mol dm −3 LiPF 6 -propylene carbonate (PC)/dimethyl carbonate (DMC) (1:1, v/v) electrolyte for lithium ion batteries. The electrochemical properties of the electrolyte with MPBMDS were characterized by discharge/charge tests, cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The addition of MPBMDS can effectively prevent the decomposition and the co-intercalation of PC. In addition, burning tests showed that the addition of 4–13 wt.% MPBMDS to the bare PC-based electrolyte effectively reduces the flammability. This eco-friendly compound provides a new promising direction for the development of bi- or multi-functional additives for lithium ion batteries.

A foaming process was used to prepare porous polymer membranes (PPMs) based on poly(vinylidene diflouride-co-hexafluoropropylene) copolymer for lithium ion batteries. In this simple process, urea, the foaming agent, was decomposed into gases and was removed at an elevated temperature to get the porous structure within the polymer matrix. When the weight ratio of urea to P(VDF-HFP) is 5:6, the PPM presents the highest porosity, 70.2%, and the prepared gelled polymer electrolyte shows an ionic conductivity up to 1.43 × 10 −3 S cm −1 at room temperature. This provides another way to prepare gelled polymer electrolytes easily for application in rechargeable lithium batteries.

The electrochemical behavior of a commercial LiCoO2 with spherical shape in a saturated Li2SO4 aqueous solution was investigated with cyclic voltammetry and electrochemical impedance spectroscopy. Three redox couples at ESCE = 0.87/0.71, 0.95/0.90 and 1.06/1.01 V corresponding to those found at E Li / L i + = 4.08 / 3.83 , 4.13/4.03 and 4.21/4.14 V in organic electrolyte solutions were observed. The diffusion coefficient of lithium ions is 1.649 × 10−10 cm2 s−1, close to the value in organic electrolyte solutions. The results indicate that the intercalation and deintercalation behavior of lithium ions in the Li2SO4 solution is similar to that in the organic electrolyte solutions. However, due to the higher ionic conductivity of the aqueous solution, current response and reversibility of redox behavior in the aqueous solution are better than in the organic electrolyte solutions, suggesting that the aqueous solution is favorable for high rate capability. The charge transfer resistance, the exchange current and the capacitance of the double layer vary with the charge voltage during the deintercalation process. At the peak of the oxidation (0.87 V), the charge transfer resistance is the lowest. These fundamental results provide a good base for exploring new safe power sources for large scale energy storage.

Graphitic carbon was coated with nano-TiO 2 by a simple mechanical process. X-ray diffraction and scanning electron microscopy were used to measure the crystal structure and surface morphology of the coated composite. Tests of galvanostatic discharge and charge and cyclic voltammograms suggest that the decomposition of propylene carbonate and the exfoliation of graphite are greatly suppressed. Lithium ions can reversibly intercalate into and deintercalate from the TiO 2 -coated graphite, and quite stable cycling behavior in propylene carbonate-based electrolyte is achieved.