LiF-coated LiMn₂O₄ samples were prepared via a chemical method. X-ray diffraction (XRD) patterns show that the bare LiMn₂O₄ and the LiF-coated LiMn₂O₄ samples are all spinel structure in space group. The apparent morphologies, the spectroscopic properties and the LiF distributions of the as-prepared samples were studied by scanning electronic microscopy (SEM), Fourier infrared spectroscopy (FTIR), transmission electronic microscopy (TEM), selected area electron diffractometry (SAED) respectively. The LiF-coated LiMn₂O₄ gets a more stable surface than bare LiMn₂O₄, and changes the interaction between the cathode material and the electrolyte. Therefore, it can endure overcharge in the secondary lithium batteries, and achieve better electrochemical performances even when charged to 4.7 V and 4.9 V.

A recycling process including separation of electrode materials by ultrasonic treatment, acid leaching, Fe-removing, precipitation of cobalt, nickel, manganese and lithium has been applied successfully to recycle spent lithium-ion batteries and to synthesize LiNi_1/3Co_1/3Mn_1/3O₂. When ultrasonic treatment with 2-nitroso-4-methylphenol(NMP) at 40 ℃ for 15 min, the electrode materials are separated completely. Above 99% of Co, Ni, Mn and Li, 95% of Fe in the separated electrodes are acid-leached in the optimized conditions of 2 mol/L H₂SO₄, 1׃2 H₂O₂׃H₂SO₄ (molar ratio), 70 ℃, 1׃10 initial S׃L ratio, and 1 h. 99.5% of Fe and less than 1% of Co, Ni, Mn in the leaching solution can be removed in the conditions of initial pH value 2.0−2.5 adjusted by adding 18% Na₂CO₃, 90 ℃ and stirring time 3 h. After adjusted to be equal by adding NiSO₄, CoSO₄ and MnSO₄ solution, 97.1% of Ni, Co, Mn in the Fe-removing surplus leaching solution can be recovered as Ni_1/3Co_1/3Mn_1/3(OH)₂. 94.5% of Li in the surplus filtrate after the deposition of Co, Ni and Mn can be recovered as Li₂CO₃. The LiNi_1/3Co_1/3Mn_1/3O₂, prepared from the recovered compounds, is found to have good characteristics of the layered structure and elecrtochemical performance.

LiCoO₂ was separated from Al foil with dimethyl acetamide(DMAC), and then polyvinylidene fluoride(PVDF) and carbon powders in active material were eliminated by high temperature calcining. The content of the elements in the recovered powders were analyzed. Then the Li₂CO₃ was added in recycled powders to adjust molar ratio of Li to Co to 1.00, 1.03 and 1.05, respectively. The new LiCoO₂ was obtained by calcining the mixture at 850 ℃ for 12 h in air. Structure and morphology of the recycled powders and resulted sample were observed by XRD and SEM technique, respectively. The layered structure of the LiCoO₂ is improved with the decrease of molar ratio of Li to Co. The charge/discharge performance, and cyclic voltammograms performance were studied. The recycle-synthesized LiCoO₂ powders, whose molar ratio of Li to Co is 1.0, is found to have the best characteristics as cathode material in terms of charge—discharge capacity and cycling performance. And the cyclic voltammograms(CV) curve shows the lithium extraction/insertion characteristics of the LiCoO₂ well.

Sn thin film on Cu foil substrate as the anode of lithium ion battery was prepared by direct current magnetron sputtering(DCMS). The surface morphology, composition and thickness and the electrochemical behaviors of the prepared Sn thin film were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), inductively coupled plasma atomic emission spectrometry(ICP), cyclic voltammetry(CV) and galvanostatic charge/ discharge(GC) measurements. It is found that the Sn film is consists of pure Sn with an average particle diameter of 100 nm. The thickness of the film is about 320 nm. The initial lithium insertion capacity of the Sn film is 771 mA∙h/g. The reversible capacity of the film is 570 mA∙h/g and kept at 270 mA∙h/g after 20 cycles.

The uniform layered Li(Ni_1/3Co_1/3Mn_1/3)O₂ cathode material for lithium-ion secondary batteries were synthesized by using (Ni_1/3Co_1/3Mn_1/3)(OH)₂ synthesized by a liquid phase co-precipitated method as precursors and with NiSO₄, CoSO₄, MnSO₄ and NH₃·H₂O as raw materials. The influence of the preparation conditions such as precursors preparation, calcinations temperature and calcinations time on the structural and electrochemical properties of the Li(Ni_1/3Co_1/3Mn_1/3)O₂ were systematicelly studied. The result of XRD shows the I₀₀₃/I₁₀₄ value of the Li(Ni_1/3Co_1/3Mn_1/3)O₂ powder synthesized at 950 ℃ for 10 h is 1.26, which illustrates the well-ordered layer-structure. The average particle size of uniform Li(Ni_1/3Co_1/3Mn_1/3)O₂ powder is about 400 nm in diameter as observed by scanning electron microscopy. The first discharge capacity of Li(Ni_1/3Co1_/3Mn_1/3)O₂ electrode is 174.6 mA∙h/g at 16 mA/g between 2.8 V and 4.5 V versus Li at room temperature, and the capacity retention is 95.2% of the initial discharge capacity after 50 cycles at 32 mA/g.

LiNi_0.5Mn_1.5O₄ was synthesized by two different coprecipitation methods: composite carbonate process and composite hydroxide method. The effects of calcination temperature of precursors on the physical properties and electrochemical performance of the samples were investigated. The results of scanning electron microscopy(SEM) show that as calcination temperature increases, the crystallinity of the samples is improved, and their grain sizes are obviously increased. X-Ray diffraction(XRD) data show that the LiNi_0.5Mn_1.5O₄ compounds obtained by two coprecipitation methods both exhibit a pure cubic spinel structure without any impurities. Furthermore, it is found that the samples prepared with relatively high temperature precursors present large initial discharge capacity (＞125 mA∙h/g) and excellent cycling stability with a capacity retention rate larger than 91% after 30 cycles at current density of 1 C. This probably derives from their higher crystallinity and larger grain sizes. However, the initial discharge capacity of LiNi_0.5Mn_1.5O₄ synthesized by composite carbonate process is smaller than that prepared by composite carbonate process, but it shows better capacity retention ability.

To improve the safety of lithium-ion batteries, dimethyl methyl phosphonate(DMMP) was used as a flame-retardant additive in a LiPF₆ electrolyte solution. The flammability and thermal stability of DMMP-containing electrolyte was investigated by means of burning test and accelerating rate calorimeter. It was found that the flammability and self-heat rate of the electrolyte can be reduced by the addition of DMMP. On the other hand, the electrochemical performances of graphite/LiCoO₂ cells become slightly worse after using DMMP additive in the electrolyte. This alleviated trade-off between electrolyte flammability, thermal stability, and cell performance provides a possibility to formulate a nonflammable electrolyte containing DMMP and improve the electrolyte thermal stability with a minimal sacrifice in performance.

The influence of nanostructure on the electrochemical properties of Li-ion battery was investigated. Tin-oxide nanotubes were prepared by combining sol-gel method with polycarbonate template. Scanning electron microscopy and X-ray diffractometry were applied to characterize the obtained material. The electrochemical measurements were conducted on the nanostructured tin-oxides as electrode of Li-ion batteries. The XRD data indicate that the wall of tube is composed of cassiterite crystals of several nanometers. The electrochemical measurements show that the reaction under potential 0.1−0.2 V is possibly related to the tubular structure of the material. It is suggested that the trapping of Li by dangling bonds and defects sites also contributes to the larger irreversible capacity loss in the first discharge.

Tin carbon nanotube (Sn-CNTs) composite was prepared by ultrasonic-electrodepositing tin on the substrate of copper foil in a sulfate bath containing carbon nanotubes (CNTs). The composites were characterized by scanning electron microscopy (SEM), cyclic voltammetry(CV) and charge-discharge cycling test. The results show that Sn-CNTs have a better electrochemical performance than Sn. The capacity of Sn-CNTs is 843 mA∙h/g during the first discharge and the efficiency of charge-discharge reaches 85%. After 50 cycles, the capacity of Sn-CNTs keeps at 380 mA∙h/g. The CNTs in tin act as a structure supporter and play a role of an elastomer and conductive network, alleviating the electrode dilapidation resulted from volume change during the lithium insertion and deinsertion.

Spinel LiNi_0.05Mn_1.95O₄ cathode material for lithium ion batteries was synthesized by solid-state reaction from coprecipitated Ni-Mn hydroxide precursors and characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and galvanostatic charge-discharge tests. It is found that LiNi_0.05Mn_1.95O₄ powder has an ordered cubic spinel phase (space group  and exhibits superior rate capability. After 450 cycles, the LiNi_0.05Mn_1.95O₄/carbonaceous mesophase spheres(CMS) Li-ion batteries can retain 96.0% and 93.3% capacity at 5C and 10C charge/discharge rate, respectively, compared with 85.3% (5C) and 80.5% (10C) retention for LiMn₂O₄ batteries. However, the initial discharge capacity of LiNi_0.05Mn_1.95O₄/CMS batteries at 1C charge/discharge rate (96.20 mA∙h/g) is slightly lower than that of the LiMn₂O₄ batteries (100.98 mA∙h/g) due to the increased average oxidation state of Mn in LiNi_0.05Mn_1.95O₄.

AB₅ hydrogen storage alloys La_0.54Ce_0.28Pr_0.18Ni_4−xCo_0.6Mn_0.35Al_x (x=0.1, 0.2, 0.3) were prepared by arc melting method under an Ar atmosphere. The results show that the contents of Ni and Al have obvious influences on the microstructure and electrochemical properties of the alloys. Both the lattice parameters and the cell volumes decrease with decreasing x value. Moreover, the discharge capacity at different temperatures, the high rate discharge property, and the cycling life of the alloy electrode are also in close relationship with the x value. When x value increases from 0.1 to 0.3, the discharge capacities with a discharge current density of 60 mA/g slightly decreases at 25 ℃, but evidently deteriorates at −40 ℃, the high-rate property gravely decreases, and the cycle life of the alloy electrode is improved in some extent. Therefore, it is meaningful to control Al content for the AB₅ hydrogen storage alloys used in Ni/MH batteries.

Hydrogen desorption behaviors of zirconium hydride at temperature range of 100−900 ℃ in mixture gases of helium and oxygen was studied by gas phase analysis(GPA). Meanwhile, the morphologies of the oxide scale formed on the surface of zirconium hydride were analyzed by scanning electron microscopy(SEM). The hydrogen desorption is retarded effectively when zirconium hydride is exposed to an oxygen containing atmosphere. Hydrogen desorption in mixed gas of helium and oxygen starts at 525 ℃ and reaches maximum at 660 ℃ and ends eventually at 800 ℃. No hydrogen desorption is found at the temperature range from 800 ℃ to 900 ℃. An oxide scale with approximately 20 μm in thickness formed on the surface of zirconium hydride acts as an effective diffusion barrier.

The intermetallic compound Zr_1−xHf_xCo and Zr_1−xSc_xCo (x=0, 0.1, 0.2, 0.3) were prepared and their suitability for hydrogen storage was investigated. The alloys show single cubic phase identical with ZrCo by X-ray diffraction. Pressure- composition-temperature(PCT) measurement results show that the equilibrium dehydrogenation pressure of Zr_1−xHf_xCo alloy increases obviously with increasing Hf content while it, changes little with increasing Sc content for Zr_1−xSc_xCo alloy. The dehydrogenation temperatures for supplying 100 kPa hydrogen are about 673, 627, and 650 K for ZrCo, Zr_0.7Hf_0.3Co and Zr_0.7Sc_0.3Co alloy, respectively. Thermodynamics calculation results indicate that dehydrogenation ΔH for Zr_1−xHf_xCo alloy decreases with increasing Hf content but increases with increasing Sc content for Zr_1−xSc_xCo alloy, which are coincident with their dehydrogenation property. The maximal hydrogen storage capacity of both Zr_1−xHf_xCo and Zr_1−xSc_xCo alloy at room temperature are high enough.

Photocatalyst hydrogen storage alloys(PHSA) with different photocatalyst contents were synthesized by mechanical blend method. The effects of the photocatalyst on the electrochemical performance of the PHSA were studied. The results indicate that the PHSA electrodes show better activation performance when UV irradiation is present. The high rate discharge performance as well as cycle performance is improved compared with that of the AB₅ alloys. The PHSA shows the best performance when the photocatalyst content is 20%.

The effects of Mn content on microstructure and electrochemical properties of LaNi_4.2−xCo_0.6Mn_xAl_0.2 alloys were investigated systematically. The results of XRD analyses indicate that the substitution of Mn does not change the crystal structure, but along with the increase of Mn substitution quantity, the volume of the crystal increases and the ratio of axial to radial lattice parameters (a/c) first increases, then decreases. With the increase of Mn substitution quantity in LaNi_4.2−xCo_0.6Mn_x Al_0.2, the discharge capacity, charge efficiency, the self-discharge and high rate discharge capacity increase first and then decrease. The discharge capacity reaches the highest value of 367 mA∙h/g (x=0.1) at 0.2C.

The double-roller rapid quenching technology was successfully used to prepare La-Mg-Ni system hydrogen storage alloys. The effects of magnesium content and heat-treatment process on the alloys properties were studied. When the alloy with 1.09%(mass fraction) Mg is heat treated at 900 ℃ for 4 h , its discharge capacity is more than 380 mA∙h/g at 0.2C, and the cyclic life is beyond 500 counts at 2C. By XRD and PCI analyzing, the results show that the alloys are composed of LaNi₅ and LaNi₃ phase. The hydrogen absorption/desorption pressure of the alloy increases, so does the slope of plateau, and the plateau becomes broad first and narrow again as Mg content increases. This method is simple to be suitable for production on a large scale.

The hydrogen storage properties of four LaNi_5−xAl_x (x = 0.25, 0.50, 0.75, 1.00) pseudobinary alloys were systematically studied. The characteristics of microstructure before and after hydrogenation, activation, kinetics and thermodynamics properties, as well the anti-combustibility properties of the four pseudobinary alloys were investigated. The results reveal that the alloys have excellent activation properties and kinetics properties. X-ray diffraction analysis of crystal lattice of the alloys show that the crystal structures of alloys do not change with the addition of Al in the range of 0≤x≤1, but the lattice constants slightly increase. It is found by measuring thermodynamic properties of the alloy-H₂ systems that with increasing x value the equilibrium pressure, hydrogen-absorbing ability and hysteresis decrease, whereas the absolute value of the enthalpy increases. It is also found that the hydrogen absorbing velocity of the alloys decreases with increasing x value.

The influence of the addition of Cu(OH)₂ to 6 mol/L KOH alkaline electrolyte on the electrochemical properties of La₂Mg_0.9Al_0.1Ni_7.5Co_1.5 hydrogen storage alloy electrode was investigated by electron probe X-ray microanalysis(EPMA), X-ray diffraction(XRD) and electrochemical measurements. EPMA micrographs and XRD patterns show that the surface of the hydride electrode is plated by metal copper film. The thickness and compactness of Cu film increase with the increment of charge-discharge cycle number. The copper film of the hydride electrode surface can keep the hydrogen storage alloy particle in the electrode interior from oxidizing availably. The addition of Cu(OH)₂ to alkaline electrolyte lowers the activation property and the high rate dischargeability of the La₂Mg_0.9Al_0.1Ni_7.5Co_1.5 hydride electrode, but has no negative effect on the maximum discharge capacity of the hydride electrode. Moreover, it is effective to improve the cyclic stability of the hydride electrode utilizing electrodeposit Cu film on the La₂Mg_0.9Al_0.1Ni_7.5Co_1.5 hydride electrodes surface.

Low-temperature performance and high-rate discharge capability of AB₅-type non-stoichiometric hydrogen storage are studied. X-ray diffraction(XRD), pressure-composition-temperature(PCT) curves and electrochemical impedance spectroscopy(EIS) are applied to characterize the electrochemical properties of AB_x (x=4.8, 4.9, 5.0, 5.1, 5.2) alloys. The results show that the non-stoichiometric alloys exhibit better electrochemical properties compared with that of the AB₅ alloy.

The as-prepared Ti-Zr hydride powder is used as dopant to improve hydrogen storage properties of NaAlH₄ upon mechanical milling under argon atmosphere. The as-milled sample is investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM) and Sievert’s technology test. It is observed that Ti-Zr hydride doped NaAlH₄ discharges 2.7% and 4.0% (mass fraction) of hydrogen in 40 min and 11 h at 160 ℃, respectively, and keeps its reversible dehydrogenation capacity at 4.0% (mass fraction) after 10 hydrogenation/dehydrogenation cycles. These results show the Ti-Zr hydride doped NaAlH₄ has good reversible hydrogen storage capacity and kinetics. XRD and SEM investigations also show that the doped Ti-Zr hydride uniformly distributes in NaAlH₄ substrate and keeps stable during the hydrogenation/dehydrogenation cycle, indicating that Ti-Zr hydride plays the main surface-catalytic role on improving reversible hydrogen storage properties of NaAlH₄.

The Co(Ⅲ)-coated spherical nickel hydroxide powder is optimum as positive electrode of high power Ni-MH battery because of its excellent property. But the performances at high temperature (above 50 ℃) is still not satisfied. In the present paper, the effect of element erbium, used as additive by different methods to prepare positive electrode, on the high temperature performances of the Ni-MH batteries is studied. It is found that the charge acceptance ability of the spherical Ni(OH)₂ electrode with element erbium as additive is improved. The discharge capacities of Ni(OH)₂ coated with 1% (atomic fraction) Er(OH)₃ and mechanically added with 1% (atomic fraction) Er₂O₃ at 1C are 12.6% and 11.7%, respectively, higher than those of the samples without erbium at 70 ℃.

Zirconia separator is one of the key materials of nickel-hydrogen battery, thereby zirconia separators are prepared by precursor process in which cellulose textiles immersed with zirconium salts are oxidized, infrared spectra show that viscose textile is an excellent precursor for preparing zirconia separator. The dominant factors in immersion are studied, it is revealed that the solution concentration and the temperature are the most important factors with regard to the area density of zirconia separator. The main reactions of immersed textiles during heat treatment are investigated by TG-DSC. The prepared zirconia separators are analyzed by SEM, XRD and infrared spectroscopy, which lead to kown that the separators maintain the same morphology of precursor textiles and contain little organic components, the main phase of the separators is tetragonal zirconia, the rate and the amount of alkaline absorption are about 5 cm/min and 220% respectively.

La_1−xSr_xCr_1−yMn_yO_3−δ(LSCM) anode materials were synthesized by glycine nitrate process(GNP). Thermo-gravimetric analysis(TGA) and differential scanning calorimetric(DSC) methods were adopted to investigate the reaction process of LSCM anode materials. The oxides prepared were characterized via X-ray diffraction(XRD), scanning electron microscope and energy dispersive spectroscopy(SEM-EDS), direct current four-electrode and temperature process reduction(TPR) techniques. XRD patterns indicate that perovskite phase created after the precursor was sintered at 1 000 ℃ for 5 h, and single perovskite-type oxides formed after the precursor were sintered at 1 200 ℃ for 5 h. The powders are micrometer size after sintering at 1 000 ℃ and 1 200 ℃, respectively. The conductivities of LSCM samples increase linearly with increasing the temperature from 250 ℃ to 850 ℃ in air and the maximum value is 32 S/cm for La_0.7Sr_0.3Cr_0.5Mn_0.5O_3−δ. But it is lower about two orders of magnitude in pure hydrogen or methane than that of the same sample in the air. TPR result indicates that LSCM offers excellently catalytic performance.

Nickel boride alloys, Ni-B, were prepared using chemical reduction method by the reaction of metal chloride with sodium borohydride, and heat-treated at various temperatures. The structures of the as-prepared alloys were studied using X-ray diffractometry (XRD), scanning electronic microscopy (SEM) and nitrogen adsorption-desorption analysis. When being adopted as the catalysts for successive hydrogen generation from sodium borohydride solution, the Ni-B alloy treated at 90 ℃ achieves a maximum hydrogen generation rate of 15.4 L/(min∙g), and an average hydrogen generation rate of 13.6 L/min, which can give successive hydrogen supply to a 2.2 kW PEMFC at a hydrogen utilization of 100%.

Nano-scale platinum catalysts were prepared on a glass carbon electrode by cyclic voltammetry. The surface morphology and active area of the catalysts, and their catalytic activity toward methanol oxidation and oxygen reduction were studied by SEM, linear and cyclic voltammetry. The result shows that the diameters of global Pt particles are affected by the scan rate of cyclic voltammetry: the faster the scan rate is, the smaller the diameters of Pt particles are. The size of the nano-scale platinum catalysts has different effects on their catalytic activity toward oxygen reduction and methanol oxidation: the catalyst with a size of 100 nm shows its best activity toward methanol oxidation, but the catalyst with a size of 65 nm shows its best activity toward oxygen reduction.

P-type thermoelectric material (Bi_0.25Sb_0.75)₂Te₃ was sintered by spark plasma sintering(SPS) process in the temperature range of 320−420 ℃. The microstructures of sintered materials were found to be well aligned, particularly when sintered at lower sintering temperatures. The electrical conductivity of the material became larger as the sintering temperature increased. The Seebeck coefficient showed a general decreasing tendency with an increase in sintering temperature. In terms of the power factor, the optimum sintering temperature was found to be 380 ℃ for a maximum value of around 2.6 mW/K.

Using potassium permanganate and acetic manganese as the reactants, amorphous manganese oxide was prepared with mechanochemical method. XRD was used for microstructure characterization, while cyclic voltammetry and constant current charge-discharge were used for electrochemical performance testing. The positive electrode (PE) and negative electrode (NE) were investigated respectively in amorphous manganese oxide supercapacitor, aiming to find their different performances in charging-discharging. The results show that the crystalline structure is destroyed in both the PE and NE material during charge-discharge process. Thereinto, the NE suffers a bit more seriously. When cycling, the PE potential scope diminishes while the NE potential scope enlarges. The increased inner resistance makes the NE curves almost bended to be a right angle, but not the PE curves. The cell’s equivalent series resistance (ESR) is more dependent on the NE, and the capacitance is mainly determined by the rapid descent of the NE potential range. The capacitances of the NE are highly rate-dependent, decreasing from 121.3 to 53.1 F/g, by 56.2%, over the range of 5−25 mV/s. However, the PE appears to be weakly dependent and its capacitance is only dropped by 22.1%.

For thermal energy storage application in energy-saving building materials, silica microcapsules containing phase change material were prepared using sol-gel method in O/W emulsion system. In the system droplets in microns are formed by emulsifying an organic phase consisting of butyl-stearate as core material. The silica shell was formed via hydrolysis and condensation from tetraethyl silicate with acetate as catalyst. The SEM photographs show the particles possess spherical morphology and core-shell structure. The as-prepared silica microcapsules mainly consist of microsphere in the diameter of 3−7 μm and the median diameter of these microcapsules equals to 5.2 μm. The differential scanning calorimetry (DSC) curves indicate that the latent heat and the melting point of microcapsules are 86 J/g and 22.6 ℃, respectively. The results of DSC and TG further testify the microcapsules with core-shell structure.

The removal of impurity phosphorus from metallurgical grade silicon is one of the major problems on purification of metallurgical grade silicon for solar grade silicon preparation. The thermodynamics on vacuum refining process of the metallurgical grade silicon was studied via separation coefficient of impurity phosphorus in the metallurgical grade silicon and vapor-liquid equilibrium composition diagram of Si-P binary alloy at different temperatures. The behaviors of impurity phosphorus in the vacuum distillation process were examined. The results show that the vacuum distillation should be taken to obtain silicon with less than    10⁻⁷ P, and the impurity phosphorus is volatilized easily by vacuum distillation in thermodynamics. Phosphorus is distilled from the molten silicon and concentrated in vapor phase.

The kinetics on vacuum refining process of metallurgical grade silicon was studied using maximum evaporation rate, critical pressure and mean free path of phosphorus in the metallurgical grade silicon at different temperatures. The behaviors of impurity phosphorus in the vacuum distillation process were examined in detail. The results show that the fractional vacuum distillation should be taken to obtain silicon with high purity. Impurity phosphorus volatilize with the maximum evaporation rate of 1.150×10⁵− 1.585×10⁶ g/(cm²·min) in the temperature range of 1 073−2 173 K and the pressure below 2.1 Pa. Because the value of w_{max, P} is at least 10⁸ times of w_{max, Si}, Si hardly evaporates and remains in the residual, which indicates that phosphorus can be removed from metallurgical grade silicon (MG-Si) completely.