Engineering WO₃ Nanostructures via Carboxylic Acid Anodization for Advanced Lithium-Ion Battery Anodes

WO₃ nanorods were fabricated following electrochemical anodization of tungsten, under controlled hydrodynamic conditions, in electrolytes containing three distinct carboxylic acids: citric, tartaric and L-aspartic acids, to study the influence of these complexing agents on the morphology and arrangement of the oxide layers. The samples were characterized by FESEM, TEM and XRD, and electrochemical analyses (EIS and ECSA) to assess their potential as anode materials for lithium-ion batteries. This characterization showed the nanostructures anodized in the presence of tartaric acid exhibit uniform morphology and lower total charge transfer resistance associated with the nanostructured layer of WO₃ and cycling stability, resulting in more efficient electrochemical processes, better conductivity and stability, making these nanostructures promising for anodes in lithium-ion batteries. The cycling of the batteries was also conducted to understand the behavior of the nanostructures as anodes against metallic lithium. The results showed that the nanostructures analyzed in the presence of tartaric acid exhibited the best initial specific capacity, improving the capacity provided by the graphite ones. These samples also showed a good recovery after faster cycling. These findings demonstrate the effectiveness of complexing-agent-assisted anodization as a strategy for tailoring WO₃ nanostructures with enhanced electrochemical performance.