Том 60, № 9 (2024)

In this work, electrocatalysts based on platinized TiO₂(Ru) oxides with different ruthenium contents were studied for usage as a working electrode for solid-state potentiometric sensors for H₂ and CO. Increasing the ruthenium content does not affect the particle size of platinum, but reduces its content in the metallic state. The work presents data from X-ray phase and X-ray fluorescence analyzes and scanning electron microscopy. The resulting electrocatalysts were studied as working electrode materials in hydrogen and carbon monoxide sensors with concentrations in the air flow from 1 to 50 000 ppm. The characteristics of the sensors are affected by the composition of the oxide carrier and its structure. For practical usage, the electrocatalysts with a rutile structure are recommended; the ruthenium content is determined by the analyzed range of CO concentrations.

Hybrid flow chemical power source: (Pt–C)H₂|Nafion|VO₂⁺(C) has been studied where the membrane-electrode assembly combines the gas-diffusion anode of hydrogen-air fuel cell (FC) and the cathode of vanadium redox flow battery (VRFB). Concept of such a hydrogen-vanadium flow battery (HVFB) had been proposed earlier (in 2013) as an alternative to VRFB, also designed for large-scale electrical energy storage but its practical implementation has so far been limited to single cells having the active area within several tens of cm². The goal of this work has been to establish the factors limiting the specific discharge power of such hybrid. HVFB cells which is inferior to both hydrogen-air FC and VRFBs, even though the HVFB cell represents a combination of their more reversible half-cells. The object of the study has been a cell of 2cm × 2cm membrane-electrode assembly equipped with Luggin’s capillary on the vanadium electrolyte side. Measurements of the current-voltage characteristics of the cell as a whole as well as the polarizations of its half-cells have been performed with the use of the six-electrode scheme of the cell connection for various circulation rates of the vanadium electrolyte and cathode materials (carbon felts 4.6 or 2.5 mm thick as well as carbon paper). It has been established that the contribution of the hydrogen gas diffusion electrode to the total DC resistance of the HVFB cell is twice that of the flow-through vanadium cathode. A record high specific discharge power has been achieved: 0.75 W cm^–2, for the cell based on the commercially available material, Sigracell GFD 2.5 EA carbon felt, as the cathode material, without its special surface modification.

This study compares the electrochemical characteristics of solid-state thin-film lithium-ion batteries with two different structures: Ti/Anode/LiPON/LiCoO₂/Ti (with an anode) and Ti/LiPON/LiCoO₂/Ti (anode-free). Si@O@Al composite anode with thicknesses of 154 and 15 nm, as well as pre-lithiated Li_xSi@O@Al composite with a thickness of 192 nm, were used as anodes. In anode-free batteries, the lithium anode was formed by the in situ method. Batteries with 154 nm Si@O@Al and Li_xSi@O@Al anodes have good cyclability due to their moderate volume change during lithium-ion insertion/extraction and reliable adhesion to the LiPON solid electrolyte. These batteries are promising in terms of high energy density due to the lithium anode formation in situ, although they have poor cycling performance due to peeling off the upper current collector. The introducing of a Si@O@Al thin film with a thickness of ~15 nm between the LiPON and the current collector allows maintaining the high energy density that is inherent in batteries with lithium anodes, while also improving their cyclability.