Collaborative Research: High-Throughput Quantification of Solid State Electrochemistry for Next Generation Energy Technologies

Project Summary The goal of this work is to combine electrochemical characterization methods (NU) with advanced microfabrication tools (Univ. of MD) and data analysis methodologies so as to enable rapid elucidation of reaction pathways and rate-limiting steps in the electrodes of energy storage and conversion devices. Such insight is a critical first step towards the rational architectural design and construction of ultra-high performance electrode structures. It further provides necessary guidance for the discovery of new chemical compositions with unprecedented energy storage and conversion properties. Intellectual Merit This work aims to dramatically advance our understanding of electrochemical reaction pathways by making use of geometrically well-defined systems. Typical electrochemical structures incorporate random, high-surface area features so as to maximize some form of performance and are not well-suited to extraction of fundamental behavior. Geometrically well-defined systems, in contrast, enable determination of properties such as length-specific triple-phase boundary activity, bulk chemical diffusion coefficient, area-specific surface activity, and much more. These are essential parameters for the deliberate engineering of high-performance structures. The painstaking nature of acquiring such data using individually prepared samples has, however, limited the study of geometrically well-defined electrochemical systems to a few important examples, despite growing recognition of its value. Here we advance the method by utilizing advanced fabrication tools to create libraries of electrodes structures on electrolyte substrates and rapidly measure the entire contents of each library using an in-house constructed, unique scanning electrochemical probe system. We further develop the computational tools to rapidly handle the massive quantity of data generated, including data mining and machine learning capabilities to create efficiencies in data acquisition and analysis. Libraries of geometrically graded microdot electrodes are complimented with selected compositionally graded libraries, with the compositional space identified to further elucidate rate-limiting steps. Thus, the work has intellectual merit by providing lasting fundamental measurements of material properties as relevant to energy technologies, and guiding the design and discovery of advanced electrochemical components. Broader Impacts Generation of new insights into electrochemical reaction pathways is an essential first step towards the creation of next-generation electrochemical energy storage and conversion devices and as such has an important role in a sustainable energy future. The breadth of analytical tools to be utilized combined with the high level of public interest in energy technologies renders this is an ideal program for training future materials scientists. Furthermore, the continued commitment of the PI and co-PI to public outreach (through, for example, the PI’s participation in the NSF sponsored documentary, “Science Nation”) will ensure that these results are disseminated to society as a whole. To engage younger students, particularly those from underrepresented groups in this research, the PI is committed to hosting two undergraduate students each summer through the NU MRSEC. The co-PI will continue outreach through the legacy programs of the UMD MRSEC, in particular, the Summer Girls Program (2-week program for girls entering 8th grade). Placement of the amassed data in a shared repository will moreover facilitate ready dissemination of the