This work introduces a new two-dimensional (2D) borophene-based (BB) supercapacitor produced by a chemical vapor deposition method and used in the facile fabrication of nanosupercapacitors (spin-coating on graphite substrates). Structural properties of the as-prepared borophene sheets are fully characterized via AFM, HRTEM, and FESEM, and Raman spectrum of the 2D sheets is scrutinized and discussed, as well as the electrochemical response of the fabricated nanosupercapacitors. A high specific capacity (sCap) of 350 F g −1 is attributed to the device according to the electrochemical tests, that is almost three times higher than previous boron-based supercapacitors and surpasses the best reported 2D materials including graphene. Based on the surface charge-storage mechanism, it is posited that the electrical conductivity and surface area of 2D electrode materials highly affect the performance of the supercapacitor. Simulation studies are also conducted using joint density-functional theory (JDFT), the results of which are in agreement with the reported outcomes of experiments. Application of the newly synthesized 2D BB supercapacitors in the current study is expected to be promising in the energy storage field, inventive class of sensing devices, as well as novel highly sensitive biosensors.

The protective coating of the electrode materials is a known source of improvement of the cycling performances in battery devices. In the case of the LiMn2O4 cathodes, the coating with a thin alumina layer has been proven to show performance efficiency. However, the precise mechanism of its effect on the performance improvement of the electrodes is still not clear. In this work we investigate alumina-coating-induced effects on the structural dynamics of the active materials in correlation to the modified solid electrolyte interface dynamics. The local structures of coated and uncoated samples at different galvanostatic points are studied by both soft X-ray absorption measurements at the Mn L-edges and O K-edge (in total electron yield mode) and hard X-ray absorption at the Mn K-edge (in transmission mode). The different probing depths of the employed techniques allowed us to study the structural dynamics both at the surface and within the bulk of the active material. We demonstrate that the coating successfully hinders the Mn3+ disproportionation and, hence, the degradation of the active material. Side products (layered Li2MnO3 and MnO) and changes in the local crystal symmetry with formation of Li2Mn2O4 are observed in uncoated electrodes. The role of alumina coating on the stability of the passivation layer and its consequent effect on the structural stability of the bulk active materials is discussed.

Pressure-induced transformations in glassy GeSe2 have been studied using the x-ray absorption spectroscopy. Experiments have been carried out at the scanning-energy beamline BM23 (ESRF) providing a micrometric x-ray focal spot up to pressures of about 45 GPa in a diamond anvil cell. Both Se and Ge K-edge experiments were performed under different hydrostatic conditions identifying the metalization onsets by accurate determinations of the edge shifts. The semiconductor-metal transition was observed to be completed around 20 GPa when neon was used as a pressure transmitting medium, while this transition was slightly shifted to lower pressures when no pressure transmitting medium was used. Accurate double-edge EXAFS (Extended X-ray Absorption Fine Structure) refinements were carried out using advanced data-analysis methods. EXAFS data-analysis confirmed the trend shown by the edge shifts for this disordered material, showing that the transition from tetrahedral to octahedral coordination for Ge sites is not fully achieved at 45 GPa. Results of present high pressure EXAFS experiments have shown the absence of significant neon
incorporation into the glass within the pressure range up to 45 GPa.

molybdenum oxides recently attracted the attention, due to the peculiar features of this class of oxide, originating from the interplay between the large variety of lattice configuration and the multiple valence states of Mo. [5][6][7] Even though MoO 3 is a high-k dielectric insulator, its electronic structure can be adjusted by modifying the oxygen substoichiometry (MoO 3−x ), introducing electronic gap states that modifies the oxide's electrical conductivity. [8,9] The stoichiometric MoO 3 is an n-type material with an equilibrium concentration of defects (mainly oxygen vacancies), which cause the formation of Mo 5+ , that partially occupies Mo 4d band creating gap states. These states play as n-type dopant, push the MoO 3 Fermi level closer to the conduction band. A continuous removal of oxygen may reduce MoO 3 to MoO 2 , the lowest stable molybdenum oxide, which contains Mo 4+ cations, that give rise to a partially filled 4d band resulting in semi-metallic states.The consequent electronic properties of the vacancy formation have shown applicability across a number of technological fields, including promising electrochromic, battery cathode material, and gas sensors. [10,11] It has also been shown thatThe phase evolution and ionic redistribution in amorphous MoO 3 films, deposited on metallic aluminium (Al) and copper (Cu) substrates and subjected to distinct thermal treatments, are systematically investigated in this work. It is shown that the metallic interface significantly modifies the formation and dynamics of oxygen vacancies within the resulted structure, reducing the oxygen content of the MoO 3 up to x < 2.94. The concentration of the oxygen vacancies can also be extended to the bulk via thermal treatment up to 400 °C. It is demonstrated that the MoO 3 structure on metallic substrates is affected either by the diffusion of the metallic atoms inserted from the interface, which results in a formation of the meta-stable alloy phases in case of Cu, or by the introduction of the oxygen vacancies into the crystalline matrix in case of Al. The oxygen vacancy density in the MoO 3 films with a metallic interface can be tuned via optimal choice of the metal and treatment parameters such as temperature and oxygen partial pressure. Furthermore, the intrinsic defects present in the amorphous structure enhance the ionic mobility and diffusion of the metallic ions inside the crystalline structure.