Functional Nanomaterials 2020: Translating Innovation into Pioneering Technologies: Translating Innovation into Pioneering Technologies II
Sponsored by: TMS Functional Materials Division, TMS: Nanomaterials Committee
Program Organizers: Simona Hunyadi Murph, Savannah River National Laboratory; Huanyu Cheng, Pennsylvania State University; Yong Lin Kong, University of Utah; Min-Kyu Song, Washington State University; Ning Zhang, Baylor University
Monday 2:30 PM
February 24, 2020
Room: Point Loma
Location: Marriott Marquis Hotel
Session Chair: Joseph Teprovich, California State University; Min-Kyu Song, Washington State University
2:30 PM Cancelled
Compact Graphene Powders with High Volumetric Capacitance: Microspherical Assembly of Graphene via Surface Modification using Cyanamide: Kwang-Bum Kim1; Young Hwan Kim1; Byung Hoon Park1; Yeon Jun Choi1; Geon Woo Lee1; 1Yonsei University
Graphene has received increasing attention as an electrode material for supercapacitors due to its high specific surface area and high intrinsic electrical conductivity. Recently, there have been tremendous achievements for improving the gravimetric capacitance of graphene. However, graphene’s low density limits its practical applications as electrode material for supercapacitors because of the unacceptably poor volumetric capacitance. To take full advantage of graphene’s superior properties, it preferably needs to be assembled into microspherical powder form with low ion transport resistance as well as high packing density. Herein, we demonstrate novel spray-drying strategy for the facile and scalable assembly of graphene into a compact microspherical powder via surface modification using cyanamide, which plays very important roles in the assembly process: preventing graphene oxide from interacting with water and restacking, polymerization into graphitic carbon nitride, and its thermal decomposition. More details will be discussed at the meeting.
2:50 PM Invited
Stress Relaxation and Battery: Hanqing Jiang1; 1Arizona State University
The successful employment of Li metal anode in Li-ion or Li-S batteries is a critical step towards realizing a cell specific density beyond 500 Wh/kg, doubling the present battery performance. While considerable progress has been made in recent years to suppress Li dendrite growth via various approaches, the long-standing issue of Li dendrite formation upon cycling has fully addressed the problem under real operation conditions. One critical and fundamental aspect has not been explored and appreciated yet, namely, electroplating-induced stress has significant role on the morphology of plated Li, which is in fact ubiquitous in metal plating. It is unclear the role of stress plays in Li dendrite growth and moreover, there is no effective approach to control the stress in plated Li to mitigate Li dendrite growth. Here we present a mechanism to release the electroplating-induced compressive stress in Li during plating through soft electrodes.
3:10 PM Invited
Photophysical and Electrochemical Properties of Fullerene and Closo-borane based Materials: Joseph Teprovich1; 1California State University, Northridge
Carbon and boron based materials such as fullerenes and the closo-borane class of structures have received considerable attention in recent years for use as active materials in energy storage and conversion applications. Their use in these applications is attributed to the ease at which their optical and electrochemical properties can be fine-tuned and tailored. This has led to their use as materials for solid state electrolytes, photoluminescent nanomaterials, hydrogen storage, and as electrodes in alkali ion batteries. Through a series of theoretical and experimental efforts it has also been demonstrated that many of these materials are multi-modal and can be utilized as the foundation for new materials with unique properties. This presentation will cover these findings and on-going developments in this class of materials.
3:30 PM
Strain Engineering of Two-dimensional Semiconductors: Sungwoo Nam1; 1University of Illinois, Urbana-Champaign
Strain engineering has been a promising approach to control exciton dynamics and photoluminescence (PL) properties of two-dimensional (2D) semiconductors. In this talk, I will present our work on deterministic straining and confinement of excitons in atomically-thin transition metal dichalcogenides (TMDs). I will discuss predictable and reconfigurable strain engineering in atomically-thin WSe2 via three-dimensional (3D) wrinkle architectures. Strain exerted on WSe2 was periodically modulated to tensile and compressive strain at peaks and valleys of the wrinkles, respectively via 3D wrinkle architecture. By tuning wrinkling parameters and encapsulation methods, we were able to achieve PL emission shift of as much as ~200 meV, corresponding to approximately 4% strain. Furthermore, owing to the deformable nature of the wrinkle architecture, the applied strain can be tuned reconfigurably by post stretching/releasing processes, with PL shift dynamically modulated. Time-resolved PL decay measurements further revealed heterogeneous exciton recombination.
3:50 PM Break
4:10 PM Invited
New Materials and Devices Beyond Silicon and Field-effect Transistors: Qing Cao1; 1University of Illinois at Urbana-Champaign
Conventional scaling of Si metal-oxide-semiconductor field-effect transistors as dictated by the Moore’s law has led to faster and more power-efficient devices with exponentially diminishing cost in the last five decades. However, it has become increasingly difficult with Si transistors approaching their physical limits. In this talk, I will review our recent efforts on exploiting novel electronic materials to realize new types of electronic devices that will potentially allow us to sustain the current pace of performance growth for solid-state electronics. On one hand, we have established carbon nanotubes as a promising material to take torch from Si for constructing the next logic switch with both better scalability into smaller footprint and processability toward monolithic three-dimensional integration. On the other hand, we suggest electrochemical random access memory based on oxides as promising device element to enable new computing paradigms beyond the von Neumann architecture.
4:30 PM Invited
Understanding Nanoscale Evolution of Materials and Interfaces in Batteries: Matthew McDowell1; 1Georgia Tech
It is critical to understand how energy storage materials transform and degrade within devices to enable the development of next-generation batteries. In my research group, multi-scale in situ techniques are used to reveal reaction mechanisms and interfacial transformations in nanostructured battery materials. Here, I will present our recent work on understanding and controlling transformations at interfaces between solid-state electrolytes and lithium electrodes within solid-state batteries, where we use interlinked in situ investigations (X-ray tomography and electron microscopy) to investigate how these interfacial transformations control chemo-mechanical degradation. Next, I will discuss investigation of phase transformation pathways in high-capacity battery electrode materials using in situ transmission electron microscopy. In particular, unexpected chemo-mechanical stability is found during reaction of conversion electrodes with alkali ions larger than Li+. This research demonstrates how fundamental understanding of dynamic processes can be used to guide the engineering of new battery materials with improved lifetime.
4:50 PM Invited
High Throughput Screening of Nano Catalysts for PEMFC/AEMFC and Machine Learning Prediction of Chemisorption
: Soonho Kwon1; Jung Woo Choi2; Hyuck Mo Lee2; 1CALTECH; 2KAIST
For rational design of new cathode nano catalysts for sluggish oxygen ORR, theoretical approaches using DFT have provided comprehensive explanations for enhanced performance of new catalysts. Based on solid concepts in heterogeneous catalysis, we conducted high-throughput screening of nano catalysts for PEMFC and AEMFC application to find a new ORR electrocatalyst. In this study, we introduce a highly durable and active catalyst candidate and describe its chemistry on the corresponding surface by higher-level of calculations for verification.Given that one has a proper size of the database for specific properties, prediction through machine learning can be a good choice. Here, using a large database from the screening performed above, we trained ANN to predict surface – adsorbate interaction to estimate the catalytic performance within an error range of < 0.2 eV. In this way, one can reduce computational cost significantly and broaden the screening window for materials exploration.
5:10 PM Cancelled
2D Conjugated Polymer Nanosheets for Photocatalytic Overall Water Splitting: Hangxun Xu1; 1University of Science and Technology of China
Conjugated polymers have emerged as a novel class of photocatalysts for solar-driven water splitting. They can offer great versatility to develop highly efficient photocatalyts with tunable electronic structures for photocatalytic applications. However, developing conjugated polymers that are able to efficiently split pure water under visible light (>400 nm) irradiation still remains a great challenge. Here I will show that 2D conjugated polymer nanosheets synthesized with suitable band structures via oxidative coupling can be used for photocatalytic overall water splitting. The reaction pathways during the photocatalytic processes can be further elucidated by using in situ spectroscopic techniques, thus providing strong evidence that the water splitting reaction occurs on the surfaces of polymer photocatalysts. Meanwhile, I will also talk about how to construct van der Waals heterostructures based on ultrathin 2D polymer nanosheets for Z-scheme overall water splitting.