Enhancing solar energy production

Research investigates ways to convert titanium dioxide into a new photoactive material in the visible light range.

The search for clean and renewable energy sources has intensified in recent years due to the increase in atmospheric concentration of greenhouse gases and the consequent increase in the average temperature of the planet. One such alternative source is the conversion of sunlight into electricity through photovoltaic panels. The efficiency in this conversion depends on the intrinsic properties of the materials used in the manufacturing of the panels, and it increases year by year with the discovery of new and better materials. As such, solar energy is expected to become one of the main sources of electric energy by the middle of this century, according to the International Energy Agency (IEA).

Titanium dioxide (TiO2) is an abundant, nontoxic, biologically inert and chemically stable material, known primarily as a white pigment used in paints, cosmetics and even toothpastes. TiO2 is also often used in sunscreens since it is especially capable of absorbing radiation in the ultraviolet region. However, this same property severely limits the use of TiO2 for solar energy conversion, since the ultraviolet emission comprises only 5 to 8% of the total energy of the solar light.

Can this TiO2 property be extended to the visible light region to increase the conversion of sunlight into electricity? To answer this question, Maria Pilar de Lara-Castells et al. [1] conducted an innovative research in which they discuss how a special treatment can change the optical properties of TiO2.

>Read more on the Brazilian Synchrotron Light Laboratory website

Real-time characterisation of a new miniature-honeycomb fuel cell

A team from Imperial College has designed a miniature ceramic solid oxide fuel cell with excellent properties and together with scientists from the University College London, the company Finden and the ESRF, they characterised the cell as it works on beamline ID15A, confirming the great performances of the new device.

Ceramic fuel cells are considered as one of the most promising technologies for sustainable energy generation thanks to their interesting features, such as higher efficiency compared to conventional combustion-based power plants, high operating temperatures (600 – 1000 °C) that generate high-grade waste heat, and superior fuel flexibility that allows the direct utilization of hydrocarbons.

To date, ceramic fuel cells are used in a wide range of applications, including stationary power supply, combined heat and power system (CHP), auxiliary power units (APU), etc., and will continue receiving attention as shale gas and biofuels are becoming the premium fuel choices thanks to their low carbon footprint.

>Read more on the European Synchrotron website

Image: Micro-computed tomography and X-ray diffraction computed tomography images. XRD-CT maps of LSM (green), YSZ (red) and NiO (blue) have been overlaid on top of a micro-CT image collected at the same z position. The scale bar corresponds to 0.5 mm.
Credit: Tao Li.

First in situ X-ray Absorption study of liquid battery cells

A greener future depends on better batteries: to move away from fossil fuels, we need rechargeable batteries with higher power and energy density to store intermittent energy from solar and wind. Moreover, these batteries could completely replace fossil fuels in vehicles.

Metal-air batteries seem like the answer, with the highest theoretical ability to pack energy into a small space (a property called energy density) of all current battery types.
“If we can achieve the theoretical energy density of metal air batteries and use them in vehicles, we can have much more driving range and make them more competitive with internal combustion engines that are currently used in cars,” says Mohammad Banis, a Western University researcher whose recent work looked at the charge and discharge cycles of a sodium-air battery in action.

Banis, who works in Andy Xueliang Sun’s clean energy research group at Western, spent a full year stationed at the Canadian Light Source to develop new tools for battery research. Observing the real time behaviour of material during charge cycles of a metal air battery presents a puzzle: the soft X-ray technique used typically requires a vacuum chamber, which makes it particularly difficult to study a liquid system.

>Read more on the Canadian Light Source website.

Image: Mohammad Banis at a Canadian Light Source beamline where he studies batteries.