University of Bath

About: University of Bath is a education organization based out in Bath, Bath and North East Somerset, United Kingdom. It is known for research contribution in the topics: Population & Photonic-crystal fiber. The organization has 15830 authors who have published 39608 publications receiving 1358769 citations. The organization is also known as: Bath University.

Surface structures and crystal morphologies of LiFePO4: relevance to electrochemical behaviour

Abstract: Advanced simulation techniques are used to provide atomic-scale insight into the surface structures and crystal morphologies of the lithium battery cathode material LiFePO4. Relaxed surface structures and energies are reported for 19 low index planes. The calculated equilibrium morphology takes on a rounded, isometric appearance, with {010}, {201}, {011}, and {100} faces prominent. Almost all of the low energy surfaces are lithium-deficient relative to the bulk lattice, requiring Li vacancies at the surface. The calculated growth morphology exhibits the {010}, {100} and {101} faces, with an elongated hexagonal prism-like shape; this morphology is more consistent with experimentally observed LiFePO4 particles. The exposure of the (010) surface in our calculated equilibrium and growth morphologies is significant since it is normal to the most facile pathway for lithium ion conduction (along the [010] channel), and hence important for the reversible insertion/de-insertion of lithium ions. SEM images of plate-like crystallites from hydrothermal synthesis are also simulated by our methods, and exhibit large (010) faces.

Developing apatites for solid oxide fuel cells: insight into structural, transport and doping properties

Abstract: Materials displaying high oxide-ion conductivity have attracted considerable interest due to technological applications in solid oxide fuel cells (SOFCs), oxygen sensors and separation membranes. This has driven research into the identification of new classes of oxide-ion conductors, and in this review, work on the recently discovered apatite-type silicate/germanate oxide-ion conductors is presented. In contrast to the traditional perovskite- and fluorite-based oxide-ion conductors, in which conduction proceeds via oxygen vacancies, the research on these apatite systems suggests that the conductivity involves interstitial oxide-ions. In addition, the flexibility of the tetrahedral (Si/GeO4) framework also plays a crucial role in facilitating oxide-ion migration. Detailed doping studies have shown that the apatite structure is able to accommodate a large range of dopants (in terms of both size and charge state), and the influence of these dopants on the conductivity is discussed.

Graphene and Rice-Straw-Fiber-Based 3D Photothermal Aerogels for Highly Efficient Solar Evaporation.

Abstract: Solar-steam generation is one of the most promising technologies to mitigate the issue of clean water shortage using sustainable solar energy. Photothermal aerogels, especially the three-dimensional (3D) graphene-based aerogels, have shown unique merits for solar-steam generation, such as lightweight, high flexibility, and superior evaporation rate and energy efficiency. However, 3D aerogels require much more raw materials of graphene, which limits their large-scale applications. In this study, 3D photothermal aerogels composed of reduced graphene oxide (RGO) nanosheets, rice-straw-derived cellulose fibers, and sodium alginate (SA) are prepared for solar-steam generation. The use of rice straw fibers as skeletal support significantly reduces the need for the more expensive RGO by 43.5%, turning the rice straw biomass waste into value-added materials. The integration of rice straw fibers and RGO significantly enhances the flexibility and mechanical stability of the obtained photothermal RGO-SA-cellulose aerogel. The photothermal aerogel shows a strong broad-band light absorption of 96-97%. During solar-steam generation, the 3D photothermal aerogel effectively decreases the radiation and convection energy loss while enhancing energy harvesting from the environment, leading to an extremely high evaporation rate of 2.25 kg m-2 h-1, corresponding to an energy conversion efficiency of 88.9% under 1.0 sun irradiation. The salinity of clean water collected during the evaporation of real seawater is only 0.37 ppm. The materials are environmentally friendly and cost-effective, showing great potential for real-world desalination applications.

Initiating action research: Challenges and paradoxes of opening communicative space

Abstract: The success or failure of an action research venture often depends on what happens at the beginning of the inquiry process: in the way access is established, and on how participants and co-researchers are engaged early on. ‘Opening communicative space’ is important because, however we base our theory and practice of action research, the first steps are fateful. We draw on Habermas’s theorizing of the boundary-crises between system and lifeworld to explore the theory behind the idea of communicative space. We attempt to bring these abstract concepts to life, and to illustrate key aspects of action research practice through a review of some of the key challenges, opportunities, and paradoxes which emerge in the early stages of action research projects. Drawing on the literature and on exemplars, we show how the process of opening communicative space can be mapped onto a theory of group development that suggests a progression through phases of inclusion, control, and intimacy. Furthermore, we review an examp...