Lithium cobalt oxide coatings on 304 stainless steel substrates have been carried out by using cathodic electrochemical synthesis in LiNO3 and Co(NO3)2 aqueous solution and subsequent annealing for thin film lithium-ion batteries. The as-deposited film is composed of the mixture of Co(OH)2·H2O and LiOH, condensed into lithium di-cobalt tetraoxide (LiCo2O4) at 310°C, and transformed into lithium cobalt dioxide (LiCoO2) and Co3O4 at 500°C, identified by X-ray diffraction (XRD) and thermal gravitational/differential thermal analysis (TGA/DTA). The two-layer structured film is observed by field emission scanning electron microscopy (FE-SEM). Cyclic voltammetry (CV) reveals the oxidation peaks at 3.75 V and 3.98 V, and the reduction peaks at 3.43 V and 3.89 V (vs. Li/Li+) for LiCo2O4 and LiCoO2, respectively. The charge/discharge test of LiCo2O4 reveals the greater reversibility and capacity at 10 μAcm−2 between 3.8 and 3.2 V (vs. Li/Li+), compared with that between 4.2 and 2.5 V. LiCo2O4, not successfully synthesized by solid state reaction at moderate temperature before, has been originally prepared by electrochemical synthesis and subsequent annealing at low temperatures (≦310°C) which could provide a suitable choice for preparing thin film lithium ion batteries applied to flexible 3C electronic products of low-cost

Summary In this research, the hydroxyapatite (HAp) could be directly deposited on carbon black (CB), which was the modified surface to generate more OH− free radicals to strengthen the bond between HAp and CB, before adding ((NH4)2Fe(SO4)2·6H2O) to engage the ion exchange with Fe2+ and Ca2+ to obtain FeHAp‐CB composites. The Pt nanoparticles were then reduced on the FeHAp‐CB composite surface to derive a Pt/FeHAp‐CB catalyst of dual function. The catalyst revealed a steep desorption peak at −0.180 V (vs Ag/AgCl) in a hydrogen oxidation reaction ascribed to the characteristics of Pt (110) facet and the CO detoxication function in the methanol oxidation reaction. The superior performance of Pt/FeHAp‐CB/CB catalyst was apparently related to the Pt (110) surface, the Fe concentration, and the homogeneous dispersion of Pt particles on the FeHAp‐CB composites. And, the ratio of coexisting Pt0 and Pt2+ within Pt/FeHAp‐CB/CB catalyst would definitely affect chemical stability and mass activity. By X‐ray photoelectron spectroscopy (XPS), it was found that a high quantity of Pt0 could improve mass activity, while a high quantity of Pt2+ contributed to chemical stability.