Cathode materials with a porous structure are important in the development of aluminum-ion batteries (AIBs). In this research, porous microspheric copper oxide (PM-CuO) composed of stacked numerous bitty nanorods has been synthesized for use in AIBs. Using a simple one-pot hydrothermal process, the-as-synthesized PM-CuO possess a large specific surface area of 21.61 m² g⁻¹ and a pore volume of 0.179 cm³ g⁻¹. These unique porous features allow PM-CuO to improve the electrochemical performance in the assembled AIBs, which exhibit a high initial charge and discharge capacity of 270.62 and 250.12 mA h g⁻¹ (current density of 50 mA g⁻¹), respectively. In the cycling performance, discharge capacity was observed to remain over 130, 121 and 112 mA h g⁻¹ at current densities of 50, 100 and 200 mA g⁻¹, respectively. The favorable properties of PM-CuO cathode materials are attributed to the unique porous structure and this makes them a promising potential material for use as energy storage devices.

The morphology evolution from monoclinic molybdenum trioxide (β-MoO ₃ ) to orthorhombic molybdenum trioxide (α-MoO ₃ ) and quantitative analyses of their mixtures were examined. It was found that the morphology (from spherical to elliptical shape) and color (from green to white) displayed obvious changes when β-MoO ₃ converted to α-MoO ₃ in ambient air at 773 K. The transformation from β-MoO ₃ to α-MoO ₃ resulted from a change of the internal crystalline structure. The mass percent of β-MoO ₃ in MoO ₃ mixtures showed an excellent linear relationship with the relative intensity ratio of the strongest peaks in X-ray diffraction patterns. This approach provides a simple and time-saving method to evaluate the amount of β-MoO ₃ , which is a promising material in catalyst and electrochemical applications, in such mixtures. This finding may provide guidance for the analysis of catalytic performance of MoO ₃ mixtures. In addition, it was found that β-MoO ₃ can be easily decomposed into suboxides such as MoO ₂ and Mo ₄ O ₁₁ in pure argon gas atmosphere. The possible decomposition mechanism of β-MoO ₃ is discussed.