Energy Materials for Sustainable Development: Fuel Cells / Storage Batteries II
Sponsored by: ACerS Energy Materials and Systems Division
Program Organizers: Armin Feldhoff, Leibniz University Hannover; Kyle Brinkman, Clemson University; Krista Carlson, University of Nevada, Reno; Eva Hemmer, University of Ottawa; Nikola Kanas, Institute Biosense, University of Novi Sad; Kjell Wiik, Norwegian University of Science and Technology; Lei Zuo, Virginia Tech; Stephanie Lee, Stevens Institute of Technology; Muhammad Hajj, Stevens Institute of Technology; Mohammad Haik, Stevens Institute of Technology

Wednesday 8:00 AM
October 20, 2021
Room: A216
Location: Greater Columbus Convention Center

Session Chair: Julia Zaikina, Iowa State University; Mona Zebarjadi, University of Virginia

8:00 AM
Magnesium-air Fuel Cell and MgO Electrolyzer: Hongyi Sun¹; Armaghan Telgerafchi²; Madison Rutherford²; Gabriel Espinosa²; Lucien Wallace²; Adam Powell²; Mahya Shahabi²; ¹University of Maryland, College Park; ²Worcester Polytechnic Institute
    A magnesium-air fuel cell (MAFC) concept delivers up to 3.5 W/cm² at 42% efficiency or 0.5 W/cm² at 80% efficiency. A low-melting molten salt electrolyte dissolves O²⁻ at cathodes and Mg²⁺ at anodes. Porous Ni or Ti cathodes maintain back pressure and create air bubbles down to the bottom of the cell, with a contact to the next Mg anode in the stack. Rising air bubbles stir away dissolved MgO, which either precipitates out and is filtered, or freezes out at the cell bottom. Salt and Mg melting points bound the operating temperature between 400°-620°C. Preliminary experiments show up to 73% of theoretical performance. Reactive cathode molten salt electrolysis with multiple-effect distillation reduces MgO back to Mg at 50-70% efficiency, leading to 40-55% round-trip efficiency, with zero direct emissions (cf. 40% for compressed or liquid H₂). Ceramic solid oxide membrane (SOM) anodes produce pure O₂.

8:20 AM
Improving Intermediate-temperature Solid Oxide Fuel Cell Anode Performance with Metal and MIEC Nanocatalyst Infiltration: Jillian Mulligan¹; Boshan Mo¹; Uday Pal¹; Srikanth Gopalan¹; Soumendra Basu¹; ¹Boston University
    Solid oxide fuel cells (SOFCs) are a promising green energy technology because of the low-impact nature of their byproducts. However, to expand their applications and improve their intermediate-temperature operation, SOFCs need to be designed with long-term stability and efficiency in mind. One method of improving performance without excessive fabrication steps involves infiltrating electrodes with nanoscale electrocatalysts, which increase the number of reaction sites. In this study, we consider the microstructure and electrochemical performance of Ni-YSZ anodes infiltrated with nickel and gadolinium-doped ceria (a mixed ionic and electronic conductor). The structure of these infiltrated anodes was characterized by scanning electron microscopy (SEM) of fracture cross-sections, and cell performance was quantified with electrochemical impedance spectroscopy (EIS). By modeling charge-transfer processes in the anode with distribution of relaxation times analysis, we explore the nanocatalyst microstructure-performance relationship in Ni-YSZ anodes.

8:40 AM
Liquid Metal Anode Direct Carbon Fuel Cell: Steven Jacek¹; Christian Faria¹; Adam Powell¹; Boyd Davis²; Yu Zhong¹; Uday Pal³; Soumendra Basu³; ¹Worcester Polytechnic Institute; ²Kingston Process Metallurgy; ³Boston University
    This talk will present performance enhancements in a liquid metal anode Direct Carbon Fuel Cell (DCFC) using a new cathode-supported electrolyte tube. The tube consists of a porous perovskite electronic conductor as current collector and support, with a porous cathode, and dense solid electrolyte outside. The liquid metal anode is an iron-tin base alloy with high carbon solubility and low liquidus temperature to facilitate very fast mass transfer. This makes the cell a cross between a solid oxide fuel cell and basic oxygen furnace steelmaking vessel. This DCFC class could potentially be used for biomass energy with carbon capture for negative-emissions electricity generation at high efficiency and with a simpler flow sheet than gasification designs. The talk will focus on the relationship between processing parameters for the cathode-electrolyte system, its structure, and its effect on performance of the overall cell.

9:00 AM  Invited
The Role of Lithium Site Occupancy on Lithium-Ion Conductivity of Tantalum-Doped Lithium Lanthanum Zirconium Oxide Garnet: Jeffrey Fergus¹; Xingxing Zhang¹; ¹Auburn University
    The lithium lanthanum zirconium oxide (LLZO) cubic garnet phase is a promising electrolyte for solid state lithium batteries due to its high lithium-ion conductivity and stability with lithium metal. In this work, tantalum-doped LLZO was synthesized by co-precipitation and sintering in a lithium-rich air environment at atmospheric pressure. The resulting materials were more than 90% dense and had lithium ion conductivities of around 4 x 10-4 S/cm. The lithium conductivity is affected by the lithium content and the distribution of the lithium between the tetrahedral and octahedral sites in the garnet phase. This relationship will be discussed in this presentation.

9:30 AM
One-step Synthesis of Carbon-coated LiCoPO₄ Nanopowders for High Voltage Battery Cathodes: V. V. Rohit Bukka¹; Pankaj Sarin¹; ¹Oklahoma State University
    An olivine-type high-voltage cathode material, LiCoPO₄, was synthesized using polymeric steric entrapment method. The synthesis procedure was modified to develop a conductive carbon coating on the active material in-situ, in a one-step process. The powders were characterized for their phase composition, particle size distribution, and surface area. The in-situ carbon-coated powders had ≈ 3% carbon by weight, with an I_G/I_D ratio of 0.75 as confirmed with Raman spectroscopy. The effectiveness of this approach was evaluated by comparing the electrochemical performance in half-cell configuration prepared with cathodes processed using these two oxide powders. Results from comprehensive cyclic-voltammetry, galvanostatic cycling and EIS studies showed that the in-situ carbon-coated powders had no adverse effects on the cathode performance. In addition, results from post-mortem XRD analysis of galvanostatically cycled cathodes will also be discussed to explain the observed coulombic efficiency.