Tânia Lopes

A novel multifunctional structural electrolyte is developed using plain–weave glass fiber reinforced with a composite polymer matrix for load‐bearing energy‐storage applications such as structural batteries. The composite matrix comprises polyvinyl alcohol (PVA) blended with epoxy, LiTFSI salt, and Al ₂ O ₃ at optimized ratios. A set of techniques is used to evaluate and optimize the thermo‐electro‐mechanical properties of the matrix, including dynamic mechanical analysis (DMA), potentiostatic electrochemical impedance spectroscopy (PEIS), thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction. The optimization reveals a clear trade‐off: increasing salt content enhances ionic conductivity but compromises mechanical properties, while the addition of nanofiller improves stiffness but reduces ionic conductivity. Based on multifunctionally balancing, a formulation of PVA _0.34 /epoxy _0.14 /LiTFSI _0.32 /(Al ₂ O ₃ ) _0.2 is obtained. The structural electrolyte, composed of glass fiber impregnated with the optimized matrix, is characterized using PEIS, DMA, tensile testing, and charge–discharge tests within lithium iron phosphate (LFP)/lithium metal and LFP/graphite cells. The electrolyte exhibits a storage modulus of 3 GPa, an ionic conductivity of 1.74 × 10 ⁻⁴ S cm ⁻¹ , a bulk stiffness of 1.82 GPa, and a tensile strength of 56.9 MPa. Full‐cell testing demonstrates long cycle life and stable cyclability for ≈240 cycles, maintaining a high Coulombic efficiency of around 95% throughout cycling.

Organic photovoltaic (OPV) cells have recently undergone a rapid increase in power conversion efficiency (PCE) under AM1.5G conditions, as certified by the National Renewable Energy Laboratory (NREL), which have jumped from 11.5% in October 2017 to 18.2% in December 2020. However, the NREL certified PCE of large area OPV modules is still lagging far behind (11.7% in July 2020). Additionally, there has been a rapidly growing interest in the use of OPVs for dim light indoor applications, with reported PCE of some large area (≥1 cm²) devices, under 1000 lux, well above 20%. The transition of OPV from the lab to the market requires the development of effective manufacturing processes that can scale‐up laboratory‐scale devices into large area devices, without sacrificing performance and simultaneously minimizing associated manufacturing costs. This review article focuses on four important challenges that OPV technology has to face to achieve a reliable lab‐to‐fab transfer, namely: i) The upscaling of indium‐tin‐oxide (ITO)‐based single cells and the interconnection of single cells into large area modules; ii) the development of alternatives to vacuum processing; iii) the development of alternatives to ITO‐based substrates; and iv) strategies for improving the lifetime of large area OPV devices.

Mitigation of ohmic losses and mass transport limitations enables a large area BiVO₄-based water splitting device with a solar-to-hydrogen efficiency of 2.1%.

Multi-layered WO3 nano-square platelets films were successfully grown on transparent TCO substrates by spray-coating of WO3 nanoparticles aqueous suspension prepared by the sol-gel method. This work assesses the influence of two annealing schemes in the photo-response of WO3 photoelectrodes with different film thicknesses. The photoelectrochemical characterization reveals that the slow-heating ramp produces a photoelectrode with an improved photocurrent density of 1.6 mA·cm-2 at 1.23 V vs VRHE. Comparing photoelectrodes with the same film thickness, the slow-heating ramp yield higher photocurrent densities; 80 % more than the conventional fast-heating ramp. The effect of the annealing ramp on the morphology and crystalline-phase structure of WO3 photoelectrodes is correlated with the photocurrent density. The slow-heating ramp annealing unveils film morphology with both, higher porosity degree and higher nano-square platelets dimensions. DRX structural analyses disclose that the films grow in monoclinic crystalline phase with a textural preferential direction (002), often related to improved photocurrent performances. The crystallite sizes and lattice microstrain are estimated using a simple X-ray diffraction broadening method, the Williamson-Hall analysis. A quantified correlation between the WO3 lattice defects, intergrains strain and performance is performed. The proposed deposition method paves the way for producing efficient and scalable photoelectrodes of WO3 for photoelectrochemical water splitting by using low-cost and simple manufacturing processes.

TiO ₂ films were prepared for facilitating the evolved gas bubbles to slip over the front window of PEC cells resulting in a transparency improvement of up to 10%.

The substrate influence on the performance of WO₃ photoanodes was studied up to 65 °C. The photocurrent increased with temperature and the onset potential shifted to lower potentials. The best operating conditions were: 45 °C for WO₃/FTO and 55 °C for WO₃/metal; the recombination rate increased for higher temperatures.