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Evaluation of bio-inspired flow fields in a mediated Li-S flow battery for grid energy storage

Marinelarena-Diaz, Asahel A.; Laros, James H.; Maraschky, Adam M.; Small, Leo J.

Lithium-sulfur is a redox flow battery with high energy density for applications in safe, reliable, and lasting scaling of energy. However, lithium-based batteries often encounter platting as a problem thanks to poor Li-ions deposition after cycling. Aiming to reduce this impact, a uniform and continuous flow of ions is needed. On this work, novel bio-inspired flow fields in the electrochemical cell were tested to improve ions flowability and lithium platting control, ultimately enhancing battery performance and life. To secure Li-S efficient, low-cost, and secure energy storage capabilities, we chose a configuration with decamethylferrocene and cobaltocene acting as redox mediators, Li metal as anode and sulfur kept in a separate catholyte reservoir. Flow test and battery results insinuated a beneficial influence of bio-inspired designs in flowing electrolyte uniformly with less pressure and pump power in comparison to other conventional designs used in the industry, with an encouraging ability to approach a cheap, safe, and reliable Li-S grid energy storage.

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TYPE Other Report YEAR 2022
DOIOSTI

A Mediated Li-S Flow Battery for Grid-Scale Energy Storage

ACS Applied Energy Materials

Laros, James H.; Rosenberg, Samantha G.; Small, Leo J.

Lithium-sulfur is a "beyond-Li-ion" battery chemistry attractive for its high energy density coupled with low-cost sulfur. Expanding to the MWh required for grid scale energy storage, however, requires a different approach for reasons of safety, scalability, and cost. Here we demonstrate the marriage of the redox-targeting scheme to the engineered Li solid electrolyte interphase (SEI), enabling a scalable, high efficiency, membrane-less Li-S redox flow battery. In this hybrid flow battery architecture, the Li anode is housed in the electrochemical cell, while the solid sulfur is safely kept in a separate catholyte reservoir and electrolyte is pumped over the sulfur and into the electrochemical cell. Electrochemically facile decamethylferrocene and cobaltocene are chosen as redox mediators to kick-start the initial reduction of solid S into soluble polysulfides and final reduction of polysulfides into solid Li2S, precluding the need for conductive carbons. On the anode side, a LiI and LiNO3pretreatment strategy encourages a stable SEI and lessens capacity fade, avoiding use of ion-selective separators. Complementary materials characterization confirms the uniform distribution of LiI in the SEI, while SEM confirms the presence of lower surface area globular Li deposition and UV-vis corroborates evolution of the polysulfide species. Equivalent areal loadings of up to 50 mgScm-2(84 mAh cm-2) are demonstrated, with high capacity and voltage efficiency at 1-2 mgScm-2(973 mAh gS-1and 81.3% VE in static cells and 1142 mAh gS-1and 86.9% VE in flow cells). These results imply that the fundamental Li-S chemistry and SEI engineering strategies can be adapted to the hybrid redox flow battery architecture, obviating the need for ion-selective membranes or flowing carbon additives, and offering a potential pathway for inexpensive, scalable, and safe MWh scale Li-S energy storage.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

Characterizing mechanical and microstructural properties of novel montmorillonite-rich polyethylene composites

Journal of Materials Science

Hill, Ryan; Peretti, Amanda S.; Small, Leo J.; Spoerke, Erik D.; Cheng, Yang T.

Montmorillonite (MMT) clays are important industrial materials used as catalysts, chemical sorbents and fillers in polymer–clay nanocomposites. The layered structure of these clays has motivated research into further applications of these low-cost materials, including use as ion exchange media and solid-state ionic conductors. In these applications, the mechanical properties of MMT are key when considering long-term, reliable performance. Previous studies have focused on the mechanical properties of nanocomposites with MMT as the minority component or pure MMT thin films. In this work, the microstructure and mechanical properties of pure MMT and majority MMT/polyethylene composites pressed into dense pellets are examined. Characterization methods such as X-ray diffraction, atomic force microscopy and scanning electron microscopy together with nanoindentation reveal important structure–property relationships in the clay-based materials. Utilizing these techniques, we have discovered that MMT processing impacts the layered microstructure, chemical stability and, critically, the elastic modulus and hardness of bulk MMT samples. Particularly, the density of the pellets and the ordering of the clay platelets within them strongly influence the elastic modulus and hardness of the pellets. By increasing pressing force or by incorporating secondary components, the density, and therefore mechanical properties, can be increased. If the layered structure of the clay is destroyed by exfoliation, the mechanical properties will be compromised. Understanding these relationships will help guide new studies to engineer mechanically stable MMT-based materials for industrial applications. Graphical abstract: [Figure not available: see fulltext.].

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TYPE Journal Article YEAR 2022
DOIOSTIScopus
Results 26–50 of 215
Results 26–50 of 215