Redox flow batteries (RFBs) are a promising solution to grid-scale energy storage that utilize solvated redox-active species to store charge. These electrolytes are flowed over stationary electrodes during charge and discharge cycling. However, solubilizing the charge storage species allows for their crossover through the separating membrane, causing electrolyte mixing, and leads to capacity fade and battery failure. Herein, we employ a series of trimethylammonium-functionalized polyethylene membranes in RFB cells to address membrane swelling in organic solvent while maintaining high counterion (PF6 –) conduction. We show unprecedented results with 99.99% average capacity retention per cycle and 88% total capacity retention through 1000 charge/discharge cycles with low crossover, as compared to a commercial membrane often used in nonaqueous RFB (NARFB) studies which retained 36% capacity. Our results represent a critical step in developing and understanding anion-exchange membranes (AEMs) as separators for NARFBs and other electrochemical systems employing organic solvents.

Hydrogen-derived power is one of the most promising components of a fossil fuel-independent future when deployed with green and renewable primary energy sources. Energy from the sun, wind, waves/tidal, and other emissions-free sources can power water electrolyzers (WEs), devices that can produce green hydrogen without carbon emissions. According to recent International Renewable Energy Agency reports, most WEs employed in the industry are currently alkaline water electrolyzers and proton-exchange membrane water electrolyzers (PEMWEs), with ∼200 and ∼70 years of commercialization history, respectively. The former suffers from inherently limited current densities due to inevitable gas crossover, operates using corrosive (7 M) alkaline solutions, and requires large installation footprints, while the latter requires expensive and scarce precious metal-based electrocatalysts. An emerging technology, the anion-exchange membrane water electrolyzer (AEMWE), seeks to combine the benefits of both into one device while overcoming the limitations of each. AEMWEs afford higher operating current densities and pressures, similar Faradaic efficiencies when compared to PEMWEs (>90%), rapid ramping/load-following responsiveness, and the use of non-noble metal catalysts and pure water feed. While recent reports show promising device performance, close to 3 A/cm 2 for AEMWEs with 1 M KOH or pure water feed, a deeper understanding of the mechanisms that govern device performance and stability is required for the technology to compete and flourish. Herein, we briefly discuss the fundamentals of AEMWEs in terms of device components, catalysts, membranes, and long-term stability/durability. We provide our perspective on where the field is going and offer our opinion on how specific performance and stability tests should be performed to facilitate the development of the field.

Anion exchange membrane water electrolyzers (AEMWEs) and fuel cells (AEMFCs) require an anion exchange membrane (AEM) with high hydroxide ion conductivity and high chemical stability to oxidative and alkaline conditions. Herein the conductivities of 17 quaternary ammonium-functionalized polyethylene-based AEMs were measured over time to understand the influence of ammonium functional groups on AEM performance. The piperidinium-based AEM containing a β-methyl in the backbone resulted in a hydroxide conductivity of 41 mS/cm at 22 °C and the highest stability with a 95% conductivity retention after 30 days in 1 M KOH at 80 °C. In fuel cell tests, increasing the ion exchange capacity of the piperidinium-based AEM led to increased performance from a peak power density of 0.7 to 1.0 W/cm 2 , enabling it to compete with other state-of-the-art AEMs after optimization.

The limited number of methods to directly polymerize ionic monomers currently hinders rapid diversification and production of ionic polymeric materials, namely anion exchange membranes (AEMs) which are essential components in emerging alkaline fuel cell and electrolyzer technologies. Herein, we report a direct coordination‐insertion polymerization of cationic monomers, providing the first direct synthesis of aliphatic polymers with high ion incorporations and allowing facile access to a broad range of materials. We demonstrate the utility of this method by rapidly generating a library of solution processable ionic polymers for use as AEMs. We investigate these materials to study the influence of cation identity on hydroxide conductivity and stability. We found that AEMs with piperidinium cations exhibited the highest performance, with high alkaline stability, hydroxide conductivity of 87 mS cm−1 at 80 °C, and a peak power density of 730 mW cm−2 when integrated into a fuel cell device.

Connecting the public to concepts in science, technology, engineering, and mathematics (STEM) is an essential for technological advancement and inspiring future scientists, impacting both the communicator and the audience's understanding of scientific topics. Without proper communication of scientific knowledge, acceptance and implementation of new technologies can be hindered. Additionally, increasing public awareness about current scientific issues through STEM engagement permits more informed policy and consumer choices, especially in the field of food science where many new food technologies are met with initial resistance by the consuming public. Here, we describe an event that introduced topics in food science to the nonexpert public, including K-8th grade participants and their adult caregivers in an informal learning environment. This program consists of six activities that collectively introduce three areas in food science: food chemistry, food microbiology, and process engineering. Protocols are provided for each activity including a materials list (with the option to scale up or down according to event duration, event space allowances, and number of participants), learning objectives and discussion points that are adaptable to different age groups, event spaces, or budgets. Each activity has a participatory component to ensure both audience member and instructor engagement. A program designed for food science communication empowers young scientific minds to better understand complex scientific topics and could inspire them to envision a possible career in STEM fields, with the additional benefit of providing graduate students an exciting medium through which they may practice their science communication skills, potentially benefiting not only their personal academic and professional skills but also broader societal needs.