Increasing local pH due to oxygen reduction induced self-discharge is the main mechanism of material dissolution and capacity fade of NaTi ₂ (PO ₄ ) ₃ electrodes in aqueous media. This problem can be strongly mitigated by ALD of a protective Al ₂ O ₃ layer.

This review focuses on the development of microbial biofuel cells to demonstrate how similar principles apply to the development of bioelectronic devices. The low specificity of microorganism-based amperometric biosensors can be exploited in designing microbial biofuel cells, enabling them to consume a broader range of chemical fuels. Charge transfer efficiency is among the most challenging and critical issues while developing biofuel cells. Nanomaterials and particular redox mediators are exploited to facilitate charge transfer between biomaterials and biofuel cell electrodes. The application of conductive polymers (CPs) can improve the efficiency of biofuel cells while CPs are well-suitable for the immobilization of enzymes, and in some specific circumstances, CPs can facilitate charge transfer. Moreover, biocompatibility is an important issue during the development of implantable biofuel cells. Therefore, biocompatibility-related aspects of conducting polymers with microorganisms are discussed in this review. Ways to modify cell-wall/membrane and to improve charge transfer efficiency and suitability for biofuel cell design are outlined.

In this research we have applied sol-gel synthesis for the deposition of tungsten (VI) oxide (WO₃) layers using two different reductants (ethanol and propanol) and applying different dipping times. WO₃ samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), photoluminescence (PL) and time-resolved photoluminescence decay methods. Photoelectrochemical (PEC) behaviour of synthesized coatings was investigated using cyclic voltammetry in the dark and under illumination. Formation of different structures in differently prepared samples was revealed and significant differences in the PL spectra and PEC performance of the samples were observed. The results showed that reductant used in the synthesis and dipping time strongly influenced photo-electrochemical properties of the coatings. Correlation between the morphology, PL and PEC behaviour has been explained.

In this research, the investigation of sensing properties of non-stoichiometric WO₃ (WO_3−x) film towards some volatile organic compounds (VOC) (namely: Methanol, ethanol, isopropanol, acetone) and ammonia gas are reported. Sensors were tested at several temperatures within the interval ranging from a relatively low temperature of 60 up to 270 °C. Significant variation of selectivity, which depended on the operational temperature of sensor, was observed. Here, the reported WO₃/WO_3–x-based sensing material opens an avenue for the design of sensors with temperature-dependent sensitivity, which can be applied in the design of new gas- and/or VOC-sensing systems that are dedicated for the determination of particular gas- and/or VOC-based analyte concentration in the mixture of different gases and/or VOCs, using multivariate analysis of variance (MANOVA).

Aqueous Na-ion based batteries are considered promising candidates for replacing Li-ion technologies, especially in the area of stationary energy storage. Research and development of novel electrode materials remain a central research effort in this field. NASICON-structured NaTi ₂ (PO ₄ ) ₃ phosphate framework has attracted a great deal of attention and remains the most studied negative electrode material for aqueous Na-ion batteries. The active material preparation and carbon composite property tailoring play a critical role in the electrode materials engineering process which governs the performance of an entire electrochemical system. We present a study of a series of aqueous sol-gel synthesized NaTi ₂ (PO ₄ ) ₃ —carbon composites using three different sol-gel approaches and three distinct pyrolysis/calcination strategies. The structural and morphological analysis shows that both the sol-gel route as well as the thermal treatment strategy have significant effects on active material purity and degree of crystallinity as well as the content and properties of the carbonaceous phase. Electrochemical investigations of these composites also show strong effects of the materials structure and carbon matrix morphology on the electrochemical performance and degradation of these materials when employed as aqueous Na-ion battery negative electrodes.