Copper oxide is considered as an alternative electrode material for supercapacitors due to its low cost, chemical stability and high theoretical specific capacitance. In the present work, nanostructured copper oxide (CuO) films are prepared by radio-frequency (RF) magnetron sputtering, and the influence of the substrate temperature on the microstructure and supercapacitive properties was studied. The copper oxide films prepared at 350 °C exhibit a predominant (1¯11) orientation corresponding to the monoclinic Cu(II)O phase with a crystallite size of 24 nm. The surface of the film consists of uniformly distributed oval-like grains providing a high surface roughness of 45 nm. The films exhibit an optical bandgap of 1.68 ± 0.01 eV and an electrical conductivity of 0.4 S cm−1 at room temperature. The as-prepared CuO films deliver a discharge specific capacitance of 387 mF cm−2 (375 F g−1) at a current density of 1 mA cm−2 with excellent cyclic capacitance retention of 95% (367 mF cm−2) even after 1000 cycles. Hence, these films are potential electrodes for micro-supercapacitors.

Three‐dimensional composites Li2TiO3/graphene (LTO/Gr) and Li2TiO3/carbon nanotube (LTO/CNTs) were synthesized by solid‐state reaction for application as anode materials for lithium‐ion batteries. These composites are structurally characterized by X‐ray diffraction, Raman spectroscopy and high‐resolution transmission electron microscopy, while electrochemically tests are performed by cyclic voltammetry and chronopotentiometry. The synergetic effect of graphene and CNTs with LTO facilitate the network conduction leading to faster electron and Li+ ion transfer and improve cycling stability and rate capability of the anode. The LTO/Gr and LTO/CNTs composites exhibited an initial discharge capacity as high as 154 and 149 mAh g−1 at 1C rate, respectively and retained excellent cycling stability of 98% and 96% after 30 charge–discharge cycles.

Li 2 TiO 3 /Ni foam composites were prepared by a solid-state reaction process. They crystallized in the monoclinic Li 2 TiO 3 structure with C 2/ c space group. SEM images show that the Li 2 TiO 3 particles are monodispersed crystallites of average size 49 nm, infused into porous scaffold Ni foam. As an anode in lithium battery, the composite delivered a discharge capacity of 153 mAh g −1 in an aqueous electrolyte and retained 95% of its initial capacity after 30 cycles. Moreover, the Li 2 TiO 3 /Ni foam composite as a negative electrode of pseudo-supercapacitor delivered a specific capacitance of 593 F g −1 and retained 95% of its initial capacitance after 1000 cycles. The enhanced capacity of Li 2 TiO 3 /Ni composite is due to porous scaffold Ni foam, which provides high conductivity to the Li 2 TiO 3 particles and high effective surface area for redox reactions. The performance of the Li 2 TiO 3 /Ni foam as an electrode material for both lithium-ion batteries (LIBs) and supercapacitors (SCs) shows that this composite is promising for energy storage devices.

In this paper, we investigate the effects of operational conditions on structural, electronic and electrochemical properties on molybdenum suboxides (MoO3-δ) thin films. The films are prepared using pulsed-laser deposition by varying the deposition temperature (Ts), laser fluence (Φ), the partial oxygen pressure (PO2) and annealing temperature (Ta). We find that three classes of samples are obtained with different degrees of stoichiometric deviation without post-treatment: (i) amorphous MoO3-δ (δ < 0.05) (ii) nearly-stoichiometric samples (δ ≈ 0) and (iii) suboxides MoO3-δ (δ > 0.05). The suboxide films 0.05 ≤ δ ≤ 0.25 deposited on Au/Ti/SiO2/flexible-Si substrates with appropriate processing conditions show high electrochemical performance as an anode layer for lithium planar microbatteries. In the realm of simple synthesis, the MoO3-δ film deposited at 450 °C under oxygen pressure of 13 Pa is a mixture of α-MoO3 and Mo8O23 phases (15:85). The electrochemical test of the 0.15MoO3-0.85Mo8O23 film shows a specific capacity of 484 µAh cm−2 µm−1 after 100 cycles of charge-discharge at a constant current of 0.5 A cm−2 in the potential range 3.0-0.05 V.

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