Charge separation and transport in La0.6Sr0.4Co0.2Fe0.8O3-δ and ion-doping ceria heterostructure material for new generation fuel cell

Functionalities in heterostructure oxide material interfaces are an emerging subject resulting in extraordinary material properties such as great enhancement in the ionic conductivity in a heterostructure between a semiconductor SrTiO3 and an ionic conductor YSZ (yttrium stabilized zirconia), which can be expected to have a profound effect in oxygen ion conductors and solid oxide fuel cells [1–4]. Hereby we report a semiconductor-ionic heterostructure La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and Sm-Ca co-doped ceria (SCDC) material possessing unique properties for new generation fuel cells using semiconductor-ionic heterostructure composite materials. The LSCF-SCDC system contains both ionic and electronic conductivities, above 0.1 S/cm, but used as the electrolyte for the fuel cell it has displayed promising performance in terms of OCV (above 1.0 V) and enhanced power density (ca. 1000 mW/cm2 at 550 °C). Such high electronic conduction in the electrolyte membrane does not cause any short-circuiting problem in the device, instead delivering enhanced power output. Thus, the study of the charge separation/transport and electron blocking mechanism is crucial and can play a vital role in understanding the resulting physical properties and physics of the materials and device. With atomic level resolution ARM 200CF microscope equipped with the electron energy-loss spectroscopy (EELS) analysis, we can characterize more accurately the buried interface between the LSCF and SCDC further reveal the properties and distribution of charge carriers in the heterostructures. This phenomenon constrains the carrier mobility and determines the charge separation and devices’ fundamental working mechanism; continued exploration of this frontier can fulfill a next generation fuel cell based on the new concept of semiconductor-ionic fuel cells (SIFCs)

Standardized procedures important for improving single-component ceramic fuel cell technology

Standardized procedures important for improving single-component ceramic fuel cell technolog

Long-Term Stability of Dye-Sensitized Solar Cells Assembled with Cobalt Polymer Gel Electrolyte

The long-term stability of a dye-sensitized solar cell (DSSC) is a key issue for upscaling and commercialization of this technology. It is well-known that gel electrolytes can improve the long-term stability and allow easy DSSC manufacturing. However, there is limited knowledge on the long-term stability of cobalt-based gel electrolytes and also how this stability is affected when applying different dye sensitizers. Moreover, long-term stability studies have been done with no, or an imperfect, sealing. In this work we investigated the performance and the stability of cobalt-based polymer gel electrolytes using devices properly sealed. Here, two different dyes, an organic and a ruthenium dye, were selected to investigate the device’s performance. The cobalt liquid electrolyte was gelled with a PEO-based terpolymer (PEO-EM-AGE) and compared to its liquid counterpart. After 1000 h, the efficiencies of the liquid- and gel-based solar cells with the ruthenium dye were statistically similar to each other. On the other hand, the DSSCs using the organic dye performed similarly by statistical analysis only up to 500 h. Our findings suggest that the choice of the dye has an important impact on the long-term stability of DSSCs and must be considered a key factor in the degradation mechanism

Semiconductor electrochemistry for clean energy conversion and storage

Semiconductors and the associated methodologies applied to electrochemistry have recently grown as an emerging field in energy materials and technologies. For example, semiconductor membranes and heterostructure fuel cells are new technological trend, which differ from the traditional fuel cell electrochemistry principle employing three basic functional components: anode, electrolyte, and cathode. The electrolyte is key to the device performance by providing an ionic charge flow pathway between the anode and cathode while preventing electron passage. In contrast, semiconductors and derived heterostructures with electron (hole) conducting materials have demonstrated to be much better ionic conductors than the conventional ionic electrolytes. The energy band structure and alignment, band bending and built-in electric field are all important elements in this context to realize the necessary fuel cell functionalities. This review further extends to semiconductor- based electrochemical energy conversion and storage, describing their fundamentals and working principles, with the intention of advancing the understanding of the roles of semiconductors and energy bands in electrochemical devices for energy conversion and storage, as well as applications to meet emerging demands widely involved in energy applications, such as photocatalysis/water splitting devices, batteries and solar cells. This review provides new ideas and new solutions to problems beyond the conventional electrochemistry and presents new interdisciplinary approaches to develop clean energy conversion and storage technologies