Nanoionics and interfaces

Contact: Dr. Alex Morata
Ongoing projects: SIGGNAL, HARVESTORE

Selected publications: Nature communications Open Access Volume 9, Issue 1, 12 November 2018, Page 4759
Large-area and adaptable electrospun silicon-based thermoelectric nanomaterials with high energy conversion efficiencies

Chemistry of Materials Volume 30, Issue 16, 28 August 2018, Pages 5621-5629
Unveiling the Outstanding Oxygen Mass Transport Properties of Mn-Rich Perovskites in Grain Boundary-Dominated La0.8Sr0.2(Mn1- xCox)0.85O3±δ Nanostructures(Article).

There is a growing interest in the development of functional metal oxides with pure ionic or mixed ionic electronic conduction for their application in different strategic fields. Ionic transport-related phenomena are of primary importance in energy transformation and storage devices, such as solid oxide fuel cells (SOFC) or batteries.

Nanoionics represents a new alternative for maximizing ionic conduction in complex oxide thin films by controlling the local compositional and microstructural modifications taking place when reducing the material dimensions to the nanoscale. By using interface-dominated materials, such as thin films, both the concentration of charge carriers and the mobility can be modified. Moreover, interface-dominated materials can also be used to enhance other mass transport phenomena, such as, for instance, the oxygen reduction reaction (ORR) capabilities of a cathode for solid oxide fuel cells or the redox reversibility of a material employed in resistive switching.

In our group, we focus on the study and understanding of nanoionics effects in transition metal oxide thin films, for their use as active components in micro solid oxide fuel cells and other power storage microdevices. The activity in this topic is covered by two major European projects, ULTRASOFC and HARVESTORE.

The interfaces between materials often play a crucial role that can even dominate the overall performance of materials and systems. Some examples can be found in the Li-ion battery field, in which interfaces between the electrodes and the electrolyte are bottlenecks for cell conductivity, thus limiting the speed of charge and the provided power. In this respect, the Nanoionics and Solid State Conversion Devices group is working in the development of all-solid state thin film batteries, pursuing transparent interfaces between different components. In the frame of the recently finished Sinergy project, founds for the fabrication of such thin film batteries were established, pursuing to store energy for autonomous Internet of Things (IoT) nodes. Moreover, our group also works on the development of micro-power generators based on thermoelectricity. One of the roles of the group in the Sinergy project was also to integrate silicon nanowires in micro-machined platforms. In the field of thermoelectrics, once again, the interfaces (between the material and the air, between grains, etc.) have proven to be the key for improving the electrical conductivity while enhancing the phonon scattering. Currently, the group participates in several projects devoted to the fabrication of nanostructures that can enhance the thermoelectric properties of the materials.