Advanced Materials for Energy Conversion and Storage: Energy Storage III
Sponsored by: TMS Functional Materials Division, TMS: Energy Conversion and Storage Committee
Program Organizers: Amit Pandey, LG Fuel Cell Systems Inc.

Thursday 2:00 PM
March 2, 2017
Room: 15A
Location: San Diego Convention Ctr

Session Chair: Partha Mukherjee, TAMU; Leela Arava, Wayne

2:00 PM  Invited
Computational Design of the Nanostructure of CNT-encapsulated-S Cathodes: Yuxiao Lin1; Jeremy Ticey2; Vladimir Oleshko2; Chunsheng Wang2; John Cumings2; Yue Qi1; 1Michigan State University; 2University of Maryland
    With precise design, CNT-encapsulated-S cathodes will enhance electronic conductivity, confine volume expansion, entrap polysulfide and avoid its dissolution, thus mitigating three major problems of Li-S battery. In this presentation, computational tools are integrated to design ideal CNT/S cathodes structure that can entrap polysulfide. By calculating the diffusion barrier of Li+ through opened rings in CNT, ideal rings with 16~30 surrounding carbon atoms (4~12 missing carbons) can selectively allow diffusion of Li+ ion while blocking both polysulfide and electrolyte. In addition, the oxidation process of CNT to form these open rings is also simulated and validated by experiments. The results indicate that the optimal open ring size can be achieved by controlling oxidation parameters. Our results also suggest that the open circuit voltage without electrolyte is higher than that with electrolyte. Combined with experiments, it can help to determine if the conversion reactions take place inside or outside CNT.

2:25 PM  Invited
Cotton-textile-enabled Flexible Energy Storage Devices: Xiaodong Li1; 1University of Virginia
    Cotton is green and renewable. The flexibility of cotton textiles provides unprecedented opportunities for constructing wearable energy devices. The activated carbon textiles converted directly from cotton not only remain mechanical flexibility but also exhibit high conductivity and porosity, ideally serving as a flexible substrate for supercapacitor and battery electrodes. We recently coated nanometer thick layers of transition metal oxides and/or graphene onto the activated carbon textiles. Such cotton templated transition metal oxide/graphene hybrid composites exhibit superior electrochemical performance. The outstanding electrochemical performance is attributed to the superstructure with significantly enhanced active-surface area, favorable morphological stability and convenient ion transport path. The hybrid nature of porous transition metal oxide and graphene jointly improve electrode's energy density and power density. A cotton-textile-enabled energy device is integrated with a flexible solar cell via a scalable roll-to-roll manufacturing approach to fabricate a self-sustaining power pack, demonstrating its potential to continuously power future electronic devices.

2:50 PM  
Monodisperse Titanium-based Perovskite Colloidal Nanocrystals for Application in Flexible Electronics: Kavey Benard1; Gabriel Caruntu1; Salemizadeh Saman1; Axel Mellinger1; 1Central Michigan University
    In this study, aggregate-free, single-crystalline titanium-based perovskite nanoparticles with controlled morphology and surface composition have been synthesized by a simple, easily scalable and highly versatile colloidal route. New insights into the growth, chemical transformations and self-organization of particles have been gained from characterization and direct imaging techniques such as XRD, TGA, TEM, AFM and PFM measurements. Piezoresponse force microscope (PFM) studies provided further evidence for the persistence of a coherent ferroelectric polarization in these particles at room temperature and capture the ultimate stability limit of the ferroelectric state. Nanoparticle-based thin films have been used to design flexible capacitors and field-effect transistors which exhibited superior performance characteristics which rival those previously reported in the literature, as a result of the high relative dielectric constant of the nanoparticle thereby making them attractive for implementation in various technological applications.

3:10 PM  
Defect Engineering of Li4Ti5O12 Anode with Enhanced Electrochemical Properties for Li Ion Batteries by Thermal Reduction: Ralph Nicolai Nasara1; Shih-kang Lin1; Ping-chun Tsai1; 1National Cheng Kung University
    Lithium titanate (Li4Ti5O12) is one of the most promising anode materials for lithium ion batteries (LIBs) because of its zero-strain property and stable operating voltage during intercalation/deintercalation. However, the intrinsic insulating property of Li4Ti5O12 hinders its high power applications. Compositing and nanonization are two well-understood approaches to overcome this drawback. Nevertheless, the effects of intentionally engineered defects in electrode materials are not as straightforward and offers another area for optimization. We engineered oxygen vacancies utilizing a thermal reduction process. Unlike the (white) Li4Ti5O12, Li4Ti5O12 with surface/sub-surface (blue) and bulk (gray) defects were synthesized. The microstructures and electrochemical properties, i.e., cycle performance and rate-capability of these Li4Ti5O12 materials were examined. In addition, ab initio calculations based on density function theory (DFT) were performed to clarify contributions of the introduced defects. The formation mechanism of the defect engineered-Li4Ti5O12 as well as the origin of enhanced electrochemical properties is elaborated in this presentation.

3:30 PM Break

3:50 PM  Invited
Challenges and Opportunities for Rechargeable Magnesium Batteries: Donald Siegel1; 1University of Michigan
    Magnesium batteries are promising next-generation energy-storage devices due to their high theoretical capacities and low raw-materials costs. Monolithic Mg negative electrodes also appear to have a smaller propensity for dendrite formation than those based on metallic lithium, making Mg a potentially safer alternative for long-lived, high-capacity batteries. Despite this promise, many challenges must be addressed at the materials level before Mg-batteries can achieve widespread commercialization. Two of these challenges relate to the development of efficient electrolytes and to the demonstration of rechargeable cathodes that approach theoretically-expected energy densities. This talk will summarize our efforts to address these issues using a combination of computational and experimental techniques. Emphasis is placed on understanding the performance of ‘Mg-air’ batteries and characterizing processes occurring at interfaces between electrodes and electrolytes.

4:15 PM  Invited
Suppressing Dendrite Growth in High Energy Density Batteries through Anisotropic Transport: Emily Ryan1; Jinwang Tan1; 1Boston University
    Dendrite formation at the electrode-electrolyte interface is a safety issue and source of performance loss in high energy density batteries, such as lithium-ion and lithium metal batteries. Controlling and suppressing the growth of dendritic structures will allow longer lifetime, higher performing batteries. In this study the use of anisotropic transport properties to suppress dendrite growth is studied. A computational model of the reactive transport at the electrode-electrolyte interface is used to study the effects of transport properties on dendrite growth. The model shows that tuning the conductivity of the electrolyte significantly effects the growth and morphology of dendrites. Additionally, materials informatics is used to investigate novel electrolyte materials that inherently produce anisotropic properties, such as ionic liquid crystals.

4:40 PM  
Electrospun Separators for Structural Battery Applications: Wisawat Keaswejjareansuk1; Jianyu Liang1; 1Worcester Polytechnic Institute
    Lithium-ion battery (LIB) has been utilized in energy storages and source. Structural battery is a new approach that employs multifunctional material concept to use LIB with load-bearing capability to minimize the weight of the complete energy consumption system and maximize the efficiency. Separator has been known as the weakest part of LIB. This work aims at creating electrospun polymer membranes with nanostructures as next generation LIB separator with improved properties. Electrospinning (ES) employs the electrostatic force to control the production of nanofibers from polymer solutions. Solution and process parameters, such as concentration of solution, ES voltage, and solution feed rate, have been studied to achieve the desirable membrane properties. In this study scanning electron microscopy, dynamic scanning calorimetry, tensile testing and electrochemical testing have been used to characterize the electrospun membranes. Design of experiments has also been utilized to optimize the parameters in creating an improved separator for structural batteries.

5:00 PM  Invited
Stabilization of Layered Battery Electrodes through Chemical Pre-intercalation of Inorganic Ions: Ekaterina Pomerantseva1; 1Drexel University
    Structural and mechanical stability of the electrode materials are necessary to achieve long cycle life of batteries. Stability of the layered electrode materials can be improved by insertion of stabilizing ions between structural layers prior to electrochemical cycling. This approach allows to controllably change interlayer distance and diffusion of the charge carriers. Moreover, stabilizing ions form additional bonds between otherwise weakly bound structural layers leading to the better electrochemical stability. In this work, we developed a wet chemistry approach to pre-intercalate various inorganic ions into the crystal structure of vanadium oxide and investigated electrochemical performance of the synthesized materials in Li-ion and Na-ion batteries. We have shown that successful chemical pre-intercalation of ions, such as Li+, Na+, K+, Mg2+ and Ca2+ results in the formation of materials with bilayered structure. We will report our findings on the effect of chemical pre-intercalation of inorganic ions on electrochemical performance layered battery electrodes.