Local Tracking of Single Ions Dynamics at Solid-Liquid Interfaces

Ions are ubiquitous in nature. They play a crucial role in countless processes, from the function of proteins rendering life possible on earth to the formation of minerals and the regulation of the ocean's acidity. In technology, ions are even more important both as structural elements for composite materials and as charge carriers in energy conversion and storage. Whether in living organisms or in cutting edge batteries, ions occupy a central role in transporting, converting and storing energy. This process usually hinges of charge exchanges that occur at the interface between a solid surface and a liquid in which the ions are dissolved.
Because of the small size of most ions, exchange and transport processes at solid-liquid interfaces tend to be dominated by structural and chemical features of the solid such as defects; much like a pillar or a puddle disturbing the natural movement of a crowed in a busy underground passage. It is therefore crucial to be able to follow single ions at the interface with immersed solids in order to fully understand ions' dynamics; any averaged measurement smears out the impact of the dominating surface features of the solid.
To date this has not been possible due a lack of experimental technique: most existing approach rely of some form of averaging over many ions in order to derive precise information.
The goal of this fellowship is to develop a novel type of microscope able to probe locally and in-situ the dynamics of single ions at the surface of immersed solids with a simultaneous spatiotemporal resolution exceeding 1 nanometre and 50 nanoseconds. This new microscope will subsequently be used uncover the molecular mechanisms enabling certain ions to migrate efficiently through composite materials while preventing others.
It will also be used to investigate the dynamics of single ions at model biointerfaces and answer otherwise inaccessible questions for biological systems. It will also be
Significantly, this experimental platform will open up the possibility to directly compare experimental results with computer simulations conducted on the same spatial and temporal scales.

The research conducted during this fellowship is expected to benefit different groups of people and potential end-users across academia, industry and the broader public:

1. Academia
The main group of short-term beneficiaries is foreseen to be academic researchers working at the cutting edge of fundamental science and technology. The unique and novel insights offered by the equipment developed during this fellowship would (i) significantly enhance the capabilities of many existing research fields and projects where ions and charged molecules at solid-liquid interfaces play an important role and (ii) enable novel research previously not possible for lack of suitable experimental techniques. This group of beneficiaries is likely to come from very diverse scientific backgrounds and may not have any expertise with scanning probe microscopy, but would be driven by specific research questions that would benefit from the new experimental insights. As non-expert end-users, it is expected that they will exploit the new technology through collaborations with expert users and, in the longer-run, direct use from commercial providers.
Aside from end-users, the research developments conducted during the fellowship may benefit academics in of scanning probe microscopy by driving the field forward. The research is also likely to benefit the field of computer simulations by opening up a new avenue for developing simulations that fully match experiments both spatially and temporally. While already possible, such simulations are rare and challenging at the present time.

2. Industry
In the short term, potential industrial end-users may benefit from the technology being developed during the fellowship and operate likely through collaborations with academics and specialised labs in order to address scientific questions pertinent to specific industrial processes and developments. In the longer term, industrial users may choose to develop the expertise to use the equipment themselves.
In parallel and on the mid-term, industry operating in the field of scanning probe microscopy may choose to enhance the prototype microscope in order to render it more user-friendly and commercialise it. This would offer the most effective route for achieving a broad impact on potential users and could be achieved through an existing collaboration with the Fellow's research laboratory.

3. Development of the UK research capabilities
As part of the fellowship's research, two postdoctoral research associate and one PhD student will be trained across the fields of high-resolution atomic force microscopy, electrochemistry, optics and computer simulations. These skills are in high demand in the UK, both in academia and in industry. Highly qualified young researchers combining several of these skills would be a great asset to the UK research capabilities and benefit the country in the long term.

4. Broder public through science outreach
The fellowship offers a unique opportunity to reach out to the broad public given the interdisciplinary and applied nature of its research. Through public lecture (Saturday Lectures Series) and events (Celebrate Science) and the developed of a simplified/macroscopic model of atomic force microscope, outreach activities will target the broader public in order to engage with non-specialist and raise the public's interest for the different research disciplines involved in the project.