Polytriphenylamine (PTPAn) was chemically synthesized and tested as a cathode material for high-rate storage and delivery of electrochemical energy. It is found that the polymer has not only superior high power capability but also high energy density at prolonged cycling. At a moderate rate of 0.5C, PTPAn gives a high average discharge voltage of 3.8 V and quite a high capacity of 103 mAh g−1, which is very close to the theoretical capacity (109 mAh g−1) as expected from one electron transfer per triphenylamine monomer. Even cycled at a very high rate of 20C, the polymer can still deliver a capacity of 90 mAh g−1 at 1000th cycle with a nearly 100% coulombic efficiency. The excellent electrochemical performances of PTPAn are explained from the structural specificity of the polymer where the radical redox centers are stabilized and protected by conductive polymeric backbone, making the radical redox and charge-transporting processes kinetically facile for high-rate charge and discharge.

Dimethyl methyl phosphonate (DMMP) was selected and tested as a non-flammable solvent for primary and secondary lithium batteries, because of its non-flammability, good solvency of lithium salts and appropriate liquidus properties. Experimental results demonstrated that DMMP can solvate considerable amount of commonly used lithium salts to form non-flammable and Li+-conducting electrolyte, which has very wide electrochemical window (>5 V vs. Li) and excellent electrochemical compatibility with metallic lithium anode and oxide cathodes. Primary Li–MnO2 cells using DMMP-based electrolyte showed almost the same discharge performances as those using organic carbonate electrolytes, and also, Li–LiMn2O4 cells using DMMP electrolyte exhibited greatly improved cycleability and dischargeability, suggesting a feasible application of this new electrolyte for constructing high performance and non-flammable lithium batteries.

FeSi6/graphite composite was prepared by mechanical ball milling. The FeSi6 alloy particles consist of an electrochemically active silicon phase and inactive phases FeSi2, distributed uniformly in the graphite matrix. The composite anode offers a large reversible capacity (about 800 mAh g−1) and good cycleability, due to the buffering effect of the inactive FeSi2 phase and graphite layers on the volumetric changes of Si phase during lithium–Si alloying reaction. Since FeSi6 alloy is a low-cost industrial material, this alloy compound provides a possible alternative for development of high capacity lithium-ion batteries.

A new fire retardant-dimethyl methyl phosphate (DMMP) was tested as a nonflammable electrolyte solvent for Li-ion batteries. It is found that in the addition of chloro-ethylene carbonate (Cl-EC) as an electrolyte additive, the electrochemical reduction of DMMP molecules can be completely suppressed and the graphite anode can be cycled very well with high initial columbic efficiency (∼84%) and excellent cycling stability in the DMMP electrolyte. The prismatic C/LiCoO2 batteries using 1.0 mol L−1 LiClO4 + 10% Cl-EC + DMMP electrolyte exhibited almost the same charge and discharge performances as those using conventional carbonate electrolytes, suggesting a feasible use of this new electrolyte for constructing nonflammable Li+-ion batteries.

Two types of Pt- and Ni-based alloy catalysts were synthesized and comparatively tested for hydrogen generation from aqueous borazane (ammonia- borane, BH3NH3)BH3NH3) solution. The experimental results demonstrated that hydrogen release rates from some of the Pt alloys such as PtRu and PtAu are nearly 9 times higher than those from pure Pt surface, and similarly, most of the Ni alloy catalysts exhibit greatly enhanced catalytic activities than pure Ni catalyst. Particularly, hydrogen release from NiAg-catalyzed BH3NH3BH3NH3 hydrolysis can complete quickly at room temperature showing a stable hydrogen yield at H2/BH3NH3ratio=2.9H2/BH3NH3ratio=2.9 (molar ratio), corresponding to 8.7 wt % hydrogen release. Since the Ni alloy catalysts are less costly and highly efficient, it is feasible to use the Ni alloy catalysts for practical hydrogen generation in portable applications.

A carbon-coated nanocrystalline LiFePO4 cathode material was synthesized by pyrolysis of polyacrylate precursor containing Li+, Fe3+ and PO4−. The powder X-ray diffraction (XRD) and high-resolution TEM micrographs revealed that the LiFePO4/C composite as prepared has a core-shell structure with pure olivine LiFePO4 crystallites as cores and intimate carbon coating as a shell layer. Between the composite particulates, there exists a carbon matrix binding the nanocrystallites together into micrometer particles. The electrochemical measurements demonstrated that the LiFePO4/C composite with an appropriate carbon content can deliver a very high discharge capacity of 157 mAh g−1 (>92% of the theoretical capacity of LiFePO4) with 95% of its initial capacity after 30 cycles. Since this preparation method uses less costly materials and operates in mild synthetic conditions, it may provide a feasible way for industrial production of the LiFePO4/C cathode materials for the lithium-ion batteries.

Ag and AgNi powders were comparatively tested as anodic catalysts for direct electrochemical oxidation of borohydride. Discharge experiments demonstrated for the first time that both Ag and AgNi electrode can catalyze the electrooxidation of borohydride, delivering a high capacity of >7e>7e oxidation for a borohydride ion. In comparison, AgNi-catalyzed borohydride fuel cells exhibited a higher discharge voltage and capacity, possibly due to a combined action of the electrocatalytic activity of Ni component for borohydride electrooxidation and the depression of borohydride hydrolysis by Ag atoms.

An electroactive polytriphenylamine (PTPAn) was synthesized and used as separator material for providing a self-activating overcharge protection of rechargeable lithium batteries. The experimental results from the Li–LiFePO4 cells demonstrated that the electroactive separator could transform from an electronically isolating state to a conductive state at overcharge, producing an resistive internal short circuit to maintain the cell's voltage at the safety value of ∼3.75 V. In addition, the electroactive PTPAn separator works reversibly and has no negative influences on the normal charge–discharge behaviors of the Li–LiFePO4 cells.

Ultrafine particles of Co–P were synthesized by direct ball milling of Co and P powders and also investigated as a reversible hydrogen storage electrode material. The electrochemical results demonstrated that the reversible charge–discharge capacity of the Co–P electrode can reach more than 300 mA h/g. In addition, the cycling ability and high rate capability of the Co–P electrode are excellent with only 5% capacity decay after 100 cycles at a high rate of 300 mA/g. The temperature-programmed desorption measurements (TPD) of the Co–P electrode revealed that the charge and discharge reactions of the Co–P electrode proceeds predominantly through electrochemical hydrogen storage mechanism and the electrooxidation of cobalt contributes only a negligible part to the reversible electrochemical capacity.

The capacity utilization of zinc anode is usually very low in dilute alkaline solution or at high rate discharge because of the passivation of zinc surface. This problem can be considerably overcome by use of surfactant additive in electrolyte. In this work, it is found that with addition of 2% sodium dodecyl benzene sulfonate (SDBS) in 20% KOH solution, the discharge capacity of zinc anode increases from 360 to 490 mAh/g at moderate discharge rate of 40 mA/g, corresponding to a 35% increase in the capacity utilization. Based on the electrochemical and morphological observation of the anodic passivation behaviors of zinc electrode, this effect is revealed that due to the SDBS adsorption, the passive layer formed on the zinc surface has a loose and porous structure rather than a dense and compact film. This type of surface layer facilitates the diffusive exchange of the solution reactant and discharged product through the surface deposit layer and therefore effectively suppresses the surface passivation of zinc anode.

An alkaline polymer gel electrolyte (PGE) film was prepared by solution polymerization of acrylate–KOH–H2O at room temperature, and the preparation conditions were optimized in view of the mechanical properties and ionic conductivity of the film. The PGE film with the optimized composition of 0.02% K2S2O8, 16.75% acrylic acid and 83.23 wt.% 4 mol l−1 KOH solution is transparent, rubber-like and dimensionally stable with improved mechanical properties as compared with gelled electrolyte. The specific conductivity of the film is 0.288 s cm−1 at room temperature and the conductivity values follow the Arrhenius equation with the activation energy of ∼10 kJ mol−1. These data suggest that the ionic conduction proceeds in the same mechanism as in aqueous alkaline solution. Experimental results from the laboratory Zn/Air, Zn/MnO2 and Ni/Cd cells using the PGE film as electrolyte demonstrate that the PGE film has almost the same chemical and electrochemical stability as aqueous alkaline solution, and shows good performance characteristics for application of alkaline primary and secondary battery systems.

A nanocrystalline Li[Li0.12Ni0.32Mn0.56]O2 powder was synthesized by a pyrolysis method using polyacrylate salts as the precursor compounds. XRD and TEM results demonstrated that the Li[Li0.12Ni0.32Mn0.56]O2 powder has a layered structure as α-NaFeO2 and has an average particle size of 50–70 nm. The charge–discharge experiments show that the Li[Li0.12Ni0.32Mn0.56]O2 electrode can deliver a reversible capacity of ∼140 mA h g−1 cycling at 2.5–4.5 V and can still remain 94% of its initial capacity after 10 cycles, showing a great promise for future applications.

The redox reaction of ferrocyanide was investigated for possible use as a redox additive for the prevention of the electrolyte decomposition of aqueous secondary Ni–MH batteries in the overcharged condition. It was found that with the presence of ferrocyanide, the charging voltage can be leveled off just above the complete oxidation of the positive nickel electrode. As a result, the oxygen evolution was greatly suppressed and the internal pressure of the batteries was kept at low level even at prolonged overcharging. In addition, no detrimental effects of the redox additive were observed on the normal charge–discharge performance of Ni–MH batteries.

A highly stable and active nickel boride catalyst (NixB) was prepared and tested for the catalytic hydrolysis of alkaline NaBH4 solution. It was found that after heat treatment at 150°C in vacuum the NixB catalyst shows greatly enhanced catalytic activity and operational stability. In the experimental conditions, the hydrolysis reaction can produce hydrogen at 45°C and hydrogen even at room temperatures, exhibiting much higher hydrogen storage capacity than currently used alloys for hydrogen storage. Since the NixB catalyst is inexpensive and easy to prepare, it is feasible to use this catalyst in the construction of practical hydrogen generators for portable and in situ applications.