bluuebunny/crossref_metadata_2025 huggingface dataset:
The Shape Influence on the Photothermal and Drug Adsorption Performance of Polydopamine Nanoparticles
Authors: Sun Yuzhe , Davis Edward
Published: February 2020

Since first reported in 2007, polydopamine synthesized in weakly alkaline condition has been extensively investigated. Among these studies, polydopamine nanospheres are commonly prepared as drug delivery nanoparticles for chemo-photothermal therapy. However, anisotropic nanostructures such as tubular shaped particles have higher specific surface area and enhanced biodistribution. But owing to the difficulty in preparation, they are rarely studied. In this study, polydopamine were fabricated into spherical and tubular shapes under weakly alkaline conditions. The nanospheres were formed in dopamine solution through a nanoprecipitation process, while hollow polydopamine nanotubes were obtained by forming a polydopamine coating on a sacrificial natural template, halloysite, in dopamine solution. Both the particles were modified with amino terminated polyethylene glycol via Michael addition. Morphology investigation showed distinct shape difference between the both nanoparticles. Under transmission electron microscopy, polydopamine nanoparticles have spherical morphology with diameters of 145-160 nm, while the nanotubes have high aspect ratios in the 4.7-5.9 range with lengths of 532-709 nm and diameters of 104-127 nm. Fourier transform infrared spectroscopy and thermogravimetric analysis were conducted to confirm both nanoparticle composition and that the template was removed completely. The photothermal effect was accessed under near infrared irradiation (808nm, 1W cm-2). The dispersions of the nanotubes, probably due to the higher specific surface, exhibited a higher temperature rise than the nanosphere dispersions. The nanotubes also displayed significantly higher loading capacity, nearly double of that for nanospheres, of an antitumor drug, doxorubicin. The release of the drug was enhanced by both acidic pH and infrared irradiation stimuli.
The Effect of Electrode Geometry and Fluid Flow on Electrodeposition of Pb2+ in Drinking Water
Authors: Lee Jaesung , Nelson Anna Marie , Burns Mark Andrew
Published: February 2020

The recent Flint Water Crisis (2014) and the failure of a lead leaching-prevention system in Newark (2018) raise concerns about health risk caused by heavy metals in water. To prevent damage from leaching of heavy metals in public water system, affordable heavy metal sensors that can continuously monitor water quality at the end point of water service lines (e.g., bathroom) for a long period are needed. We previously developed a sensor that utilized electrodeposition in a four-electrode system (anode, cathode, and two floating electrodes) to detect heavy metal ions (Pb2+, Zn2+, Cu2+, and Fe2+) in drinking water1. This sensor could detect low concentrations of heavy metal ions with 2 AAA batteries at a low per-sensor manufacturing cost (~$0.10/sensor) and a small footprint (~1 mm2). However, the response time of the sensor varied by days and the effect of fluid flow on the sensor performance has not been tested. In this presentation, we report our study about the effect of electrode geometry and fluid flow on the ability of the sensor to detect lead. We varied the number and shape of interdigitated electrodes as well as the gap width between electrodes, and we found we could reduce the response time from 103.8 ± 42.8 hr to 14.3 ± 3.2 hr. Scanning Electron Microscopy (SEM) revealed fractal and dendritic growth of the lead oxides deposited, hinting that the deposition occurs in a mass-limited condition. We also observed a differential growth speed of the lead oxides in electrode areas and a complete change of the spatial pattern of this deposition behavior in fluid flow condition.

Lin, W., Li, Z. & Burns, M. A. A drinking water sensor for lead and other heavy metals. Anal. Chem.
89, 8748-8756 (2017).
Zinc Cobalt Sulfides on N, S Co-Doped Carbon Derived from Bimetallic-Organic Framework As an Advanced Electrocatalyst for Oxygen Reduction Reaction
Authors: Hwang Minji , Lim Chaewon , Kim Sangjin , Baeck Sung-Hyeon
Published: February 2020

Recently, the environmental problems caused by excess use of fossil fuels triggered intense research for efficient, inexpensive, and harmless energy conversion and storage devices such as fuel cells and rechargeable metal air batteries. In these applications, the oxygen reduction reaction (ORR) are a key electrochemical process for commercialization. Also, developing non-noble metal-based electrocatalysts with high electrochemical performance is very important in economic point of view. To address these issues, electrocatalysts based on nanocarbon frameworks such as metal organic frameworks (MOFs) and zeolitic imidazolate framework (ZIF) have been widely investigated as promising alternatives to Pt-based catalysts. In this work, we prepared bi-metallic ZIFs by coprecipitation of zinc and cobalt ions in the presence of 2-methylimidazole, followed by one-step sulfidation and carbonization to synthesize zinc cobalt sulfides supported on N, S co-doped porous carbon. The as-synthesized catalyst maintained inherent dodecahedral particle shape of ZIF. Furthermore, it exhibits outstanding ORR onset-potential (0.96 V vs. RHE) and half-wave potential (0.83 V vs. RHE), which is comparable to commercial Pt/C catalyst in alkaline electrolyte. Such outstanding electrochemical properties are mainly ascribed to the synergistic effect of the chemical composition, high electrochemical active surface area, and abundant active sites of the dodecahedral structure. These findings suggest that the transition metal sulfides on N, S co-doped porous carbon can be a promising alternative for the next generation of energy storage and conversion technologies.
Cu/Zn SOD Detection By Catalytic Amplification for the Design of a Cancer Biosensor
Authors: Sanchez Annelis O
Published: February 2020

High levels of SOD2 are related to an increased frequency of invasion and metastasis of certain types of cancer (i.e. fibrosarcoma). Early detection of SOD2 in the circulatory or lymphatic system can help diagnosis and prognosis of these types of cancer. A highly sensitive method is required for detecting very low concentrations of this enzyme. The herein project detects collisions of a single CuZn SOD enzyme on the electrode’s surface. This detection is possible due to a catalytic amplification process occurring over the enzyme’s surface. The current transient is generated when the oxidation process occurs over the surface of the individual nanoparticle (CuZnSOD in this case) when this one impacts the ultramicroelectrode’s (UME) surface. The current blip generated is then use to calculate the enzyme's size. According to theoretical calculations, CuZn SOD has approximately 4 nm diameter. This number correlates with the size obtained by the electrochemical technique, and transmission electron microscopy (TEM) images.

Figure 1. Amperometric i vs t curve of a 0.089 fM CuZnSOD solution in phosphate buffer pH = 7.8 applying a potential of E = 0.2 V. Three electrode cell was used: a 10 μm Pt UME as the working electrode, Ag/AgCl as the reference electrode, and a Pt wire as the counter electrode.

Figure 1
Quantitative Characterization of Pseudocapacitance on Carbon-Based Active Electrode Materials
Authors: Hyun Jong Chan , Kwak Jin Hwan , Yun Young Soo
Published: February 2020

A pseudocapacitive reaction (PCR) is a surface and/or near surface charge storage behavior accompanying a charge transfer between a guest ion and host active material. The surface induced charge transfer reaction is very fast and stable, because it occurs without solid-state-diffusion of the guest ion and volume changes in the active materials. In addition, a large amount of charge surpassing that gathered from electrochemical double layer (EDL) formation can be stored by PCRs. The more compelling characteristic of the PCR is its collaborative charge storage phenomenon coinciding with EDLs. When the PCR occurs on nanoporous carbon (NPC)-based electrode materials, a drastic improvement in capacity can be achieved with preservation of their intrinsic characteristics that arise from the storage nature of the surface-driven charge. Several reports have demonstrated the superiority of NPCs with PCRs, detailing their significantly high electrochemical performances as active electrode materials for Li and Na ion batteries as well as supercapacitors. Nevertheless, there is little information for the chemisorption-based alkali cation storage behaviors on NPCs. Moreover, there is no method to characterize the level of contribution of the PCR and EDL capacitance, limiting deeper understanding of the PCR in NPCs. Herein, we focused on that the PCRs on NPCs occur through various reaction pathways which have intrinsic activation energy barriers. Therefore, voltage hysteresis of their electrochemical charge/discharge profiles is inevitable in a given voltage window. Owing to the voltage hysteresis, the charge storage capacitance is dependent on the operating voltage window, which could results in variation in the capacitance value according to the characterized voltage range. The voltage-dependent pseudocapacitive behaviors (VD-PCBs) may be used to differentiate the respective contributions of the EDL capacitance and PCR to the overall capacity of NPCs. In this study, heteroatom-enriched NPCs (H-NPCs) were prepared from a nitrogen-containing conjugated polymer precursor by pyrolysis with potassium hydroxide. The voltage-dependent charge storage behaviors of H-NPCs were then characterized by cyclic voltammetry (CV) in different electrolyte systems. From the results, it was confirmed that the pseudocapacitance value can be quantitatively measured through a comparison of CV obtained from different charge carriers. The VD-PCBs on H-NPCs were kinetically fast and highly stable, leading to a high electrochemical performance. In addition, H-NPCs-based lithium ion hybrid capacitors achieved a high specific energy of ~220Wh kg-1 and a specific power of ~5400Wkg-1 with a long-term cycle life of over 500 cycles, demonstrating the usefulness of the VD-PCBs-based H-NPCs.
Pyroprotein-Based Ultra-Thin Catalytic Layer for Sodium Metal Batteries
Authors: Kwak Jin Hwan , Hyun Jong Chan , Yun Young Soo
Published: February 2020

In this study, a thin pyroprotein seed layer (PSL, ∼100 nm thick) was coated on a Cu substrate via spin-coating with a regenerated silk fibroin (RSF) followed by pyrolysis at 800 °C. The PSLs were composed of highly disordered carbon building blocks in which Na ions can diffuse and come into contact with numerous defective carbon sites. Therefore, the homogeneous deposition of Na metal can be induced on the PSL-coated Cu electrode (PSL-Cu) at a high areal current density of ∼4 mA cm−2. The nucleation overpotential of PSL-Cu remarkably decreases by ∼10 mV, which is a much lower value than that (∼26 mV) of a bare Cu foil electrode. In addition, the PSL-Cu achieved stable Na metal deposition/dissolution during ∼300 cycles with a mean CE of ∼99.96%, which is the highest value reported for metal anodes thus far. Moreover, the PSL-based Na metal anode has a significantly low cell-to-cell variation with a CE deviation of ∼0.43%. Considering the simple fabrication process and well-established chemistry of PSL-Cu, the electrochemical performance of PSL-Cu deserves significant attention. The feasibility of PSL-Cu was further demonstrated via a full-cell experiment using a reported polyanion cathode, which revealed a high specific energy of 402 W h kg−1 at 390 W kg−1, high specific power of 3800 W kg−1 at 275 W h kg−1, and stable cycling with a capacity retention of 86% after 30 cycles. This work proves that the electrochemical performance of a metal anode can be advanced by (1) increasing the number of catalytic nucleation sites for metal electrodeposition and (2) enhancing the wettability of the electrolyte through the introduction of a large number of nucleophilic functional groups.
Electrochemistry on Tribocharged Polymers
Authors: Zhang Jinyang , Ciampi Simone
Published: February 2020

Static electrification of insulators is a familiar topic: hair attracted by a party balloon or ink or laser printers transferred to a toner1. Contact electrification develops on the surface of insulators which are brought in and out of. Statically charged surfaces has been known to mediate redox work, but the scope in electrochemistry of charged dielectrics remains poorly understood. In 2008, Liu and Bard demonstrated that metal ions can be reduced to elemental metal on a charged polytetrafluoroethylene surface and they proposed that charge carries are electrons2. However, in 2011, Bartosz A. Grzybowski demonstrated a random “mosaic” of each polymer surface after contact and separated, suggesting that polymer fragments are responsible of the electrification process3. Here we report that the magnitude of electrochemical work on electrostatically-charged polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) samples is material-dependent. We show that the magnitude of redox work mediated by a charge insulator is governed by a trade-off between its ionization energy (IE) and electron affinity (EA)4. Using XPS, AFM and TEM we have quantified metal deposition on electrostatically-charged PDMS, PTFE and PVC samples. Quantum chemical methods are used to show that anions are the effector of the redox work and polymer, with plastics of the largest negative value of EA (making negative charges unstable) but that at the same time it will ionize into cationic fragments with relative ease, leads to surfaces able to mediate redox work to the largest extent. This work extends our understanding of the molecular nature of static electricity and may find applications in single-electrode electrochemistry and in the study of electrostatic catalysis on chemical reactivity.

References

Childress, C. O.; Kabell, L. J., Electrostatic Printing System. US Patent No. 3,081,698, 163: 1963.

Liu, C.-Y.; Bard, A. J., Electrostatic Electrochemistry at Insulators. Nat. Mater.
2008,
7 (6), 505–509.

Baytekin, H.; Patashinski, A.; Branicki, M.; Baytekin, B.; Soh, S.; Grzybowski, B. A., The Mosaic of Surface Charge in Contact Electrification. Science
2011,
333 (6040), 308–312.

Zhang, J.; Rogers, F.; Darwish, N.; Gonçales, V. R.; Vogel, Y. B.; Wang, F.; Gooding, J. J.; Peiris, M. C.; Jia, G.; Veder, J.-P., Electrochemistry on tribocharged polymers is governed by the stability of surface charges rather than charging magnitude. Journal of the American Chemical Society
2019.

Figure 1
(Invited) Gender Bias in STEM Workplaces
Authors: Rincon Roberta
Published: February 2020

While we have seen an increase in women’s representation in certain STEM fields such as biology and chemistry, many engineering and technology professions have seen relatively slow increases (and, in some cases, decreases) in women’s participation. Though an increasing number of women are choosing STEM careers, many experience frustrations when trying to move up into more senior positions. Achieving gender equity in STEM requires addressing issues affecting women’s inclusion and advancement in the workplace, particularly the impact of gender bias.

A recent study found that 27% of women in the U.S. feel that their careers are stalled in STEM, with over 30% indicating thoughts of leaving their jobs within the year.1 And women in the U.S. are not alone: Women around the globe are struggling to reach higher level positions in their STEM careers, with 47% of women in China and 55% of women in India indicating that a women will never get a top position in her company, no matter how able or high-performing.2 Research indicates that one of the primary reasons for women’s attrition from the STEM workforce is workplace climate and culture. For example, one study found organizational climate was the primary factor for 30% of women who left the engineering profession, with nearly half citing working conditions such as a lack of advancement or salary.3

Addressing gender bias in the STEM workplace will help to close the gender gaps that exist in the STEM workforce. It is not just the right thing to do: Reducing women’s attrition in STEM is necessary to help meet the growing global demand for STEM talent. Studies also show that gender-balanced teams are more innovative, and companies with greater levels of gender diversity in upper management see greater financial performance than their less-diverse counterparts.4,5

Hewlett, S. A., Sherbin, L., Dieudonne, F., Fargnoli, C., & Fredman, C. (2014). Athena Factor 2.0: Accelerating Female Talent in Science, Engineering & Technology: Executive Summary.

Ibid.

Fouad, N. A., Singh, R., Fitzpatrick, M. E., & Liu, J. P. (2012). Stemming the tide: Why women leave engineering.

Kelly Services. (2016). Women in STEM: How and why an inclusive strategy is critical to closing the STEM talent gap.

McKinsey & Company. (2018). Delivering through diversity.
The Wonderful World of Scanning Electrochemical Microscopy (SECM)
Authors: Mauzeroll Janine
Published: February 2020

In its simplest form, SECM is a scanning probe technique in which a small- scale electrode is scanned across an immersed substrate while recording the current response. This response is dependent on both the surface topography and the electrochemical activity of the substrate. Consequently, using an array of operational modes, a wide variety of substrates and experimental systems can be characterized. The strength of SECM lies in its ability to quantify material flux from a surface with a high spatial and temporal resolution. It has been used in a variety of applications fields.

We will first describe the fundamentals of SECM, including the required instrumentation and the principles of the most frequently used operational modes. Following this basic understanding of SECM principles, we then move towards a comprehensive summary of the critical parameters for any SECM experiment. More specifically, we will discuss in detail redox mediators, probes, and solvent systems that are used in SECM experiments. Finally, we will discuss recent applications of SECM (2009-2015), with an emphasis on our work in the last five years related to cancer cells, corrosion and batteries.
Electrochemical Research in the Energy Industry & the Role of Interfaces
Authors: Endler Elizabeth
Published: February 2020

As the energy transition unfolds, energy generation, distribution, storage, and use are evolving rapidly. Traditionally, carbon-based fuels such as oil, coal and natural gas are readily distributed and have served as energy storage media for the power and transportation sectors. With the growth of lower-carbon energy technologies, particularly wind and solar power, there is a need for high-performing, cost-effective solutions that provide analogous storage and distribution services to traditional fuels and enable effective use of these renewable electrons.

The talk will include a brief introduction to key challenges whose solutions are central to successful, expanded deployment of electrochemical energy storage technologies. This will be followed by selected examples of ongoing electrochemical research that illustrate one energy company’s approach to R&D, in order to answer questions about fundamental phenomena that have the potential to redefine present understanding of electron storage and charge carrier transport processes and enhance the performance, energy density, and lifetime of electrical energy storage systems. Finally, elements of my professional experience will be highlighted that led me to electrochemical sciences and have been central to the global energy storage research program which I lead. These include the role and navigation of interfaces within and among technical disciplines and business functions.
(Invited) Electrochemical Production of Oxygen and Fuel on Mars
Authors: Elangovan S , Hartvigsen Joseph J , Larsen Dennis , Hafen Tyler , Adams Megan
Published: February 2020

The production of oxygen for life support and ascent vehicle propellant oxidant is essential for human expeditions to Mars. Solid oxide electrolysis (SOXE) stacks are capable of reducing carbon dioxide and water available on Mars to produce high purity oxygen. They can electrolyze CO2 or water separately or co-electrolyze CO2 and water together to produce oxygen and fuels such as methane for propulsion. OxEon’s team led the development of SOXE stacks in collaboration with the Jet Propulsion Laboratory (JPL) and Massachusetts Institute of Technology (MIT). The work resulted in delivering a set of flight qualified stacks to JPL. A packaged stack has been installed on the rover that is scheduled for launch next year for the Mars 2020 mission. The Mars Oxygen ISRU Experiment (MOXIE) will demonstrate the feasibility of producing high purity oxygen from Mars atmosphere carbon dioxide using a SOXE stack.

Since delivering the stacks, the OxEon team has designed and begun fabricating SOXE stacks of the cell area required for a manned Mars mission. Under the NASA NextSTEP-2 ISRU activity, this platform will be tested with conditions targeting the ISRU application. MOXIE testing was focused on the case of atmospheric ISRU for oxygen evolution at the anode and did not make use of the CO byproduct gas at the cathode.. In 2019, OxEon will demonstrate CO2-steam co-electrolysis to produce carbon monoxide and hydrogen (synthesis gas) on the cathode and high purity oxygen at the anode. The synthesis gas will be converted to methane in an OxEon developed methanation reactor as an alternative to a water electrolysis coupled Sabatier system.

In addition, OxEon is investigating a combination of materials and engineering solutions to improve redox tolerance of nickel-based cathode. Traditionally, SOXE stacks use nickel – zirconia or nickel – ceria composite cathode. Nickel based electrodes are susceptible to oxidation by the feed gas (CO2 or steam) at the inlet conditions unless reducing species (carbon monoxide or hydrogen) are also present. Button cell tests show that the new, modified cathode material exhibits good redox stability over multiple redox cycles with only a minor loss of performance after each cycle. Initial tests also show that under certain operating conditions the loss of performance can be recovered. Implementation of a redox tolerant cathode will eliminate the need for complex recycle loop that introduces a fraction of the product gases to the inlet in order to prevent nickel oxidation.

Acknowledgement: NextSTEP ISRU work is supported under NASA Contract 8-HQTR19C0006. The redox tolerant cathode work is done under a NASA Small Business Innovation Research Contract No. 80NSSC18P1940. The work related to MOXIE was based on support from NASA through JPL’s prime contract, under JPL subcontract number 1515459.
Electrochemical Interfacial Phenomena Under Microgravity
Authors: Fukunaka Yasuhiro , Matsushima Hisayoshi , Nishikawa Kei , Allanore Antoine , Nohira Toshiyuki , Goto Takuya , Homma Takayuki , Rosso Michel
Published: February 2020

Electrochemical Processing under extreme conditions like reduced gravity, strong cosmic ray irradiation and magnetic fields should be　well designed in the era of Gateway after ISS. JAXA’s “HAYABUSA” satellite project of Successful Sample Return from Asteroid “Itokawa” was achieved by newly developed Ion Engine and well controlled life-cycling of LIB. Now, HAYABUSA 2” is approaching to “Ryugu” asteroid by Pin-point Landing supported with Robotics & AI Image Learning (Self Controlled Driving). Moreover, Manned Rover operation plan toward Lunar Hydrogen Energy System in 2029 was announced by JAXA-TOYOTA last March. CO2 Reduction for Life Supporting System must be reasonably combined. HERACLES (Human Enhanced Robotic Architecture for Lunar Exploration and Science) and MMX (Martian Moons eXploration) shall be further planned. High Temp. Molten Oxide Electrolysis with Inert Anode are engaged as ISRU.

One of the fundamental subjects common in designing the energy conversion and storage devices in space engineering is to well control the electrochemical interfacial phenomena among three Gas/Liquid(Aqueous or Molten Oxide)/Solid(Metal or Solid Oxide) phases under reduced gravity and magnetic field. Experimental studies in Drop Tower, a parabolic flight and University Laboratory(1-G) to focus the wettability effects on these phenomena were reported over last 30 years1-10).

O2 bubble evolution behavior on Pt electrode modified by thiol SAM was monitored during alkaline water electrolysis under μ-G with a high speed video camera.　Single bubble measurements on microwire electrode was additionally engaged. The latter revealed three-step processes involving (1) the nucleation and formation of supersaturated layer of dissolved O2 gas followed by (2) a rapid growth depending on the gas diffusion process and finally (3)a stable growth where its growth rate is dominated by bubble configuration depending on the contact angle. Moreover, the correlation of multiple gas bubble observation with electrochemical data and surface coverage on the plate electrode reinforces the importance of wettability in determining two phase flow motion and energy consumption during electrolysis. The degree of supersaturation of dissolved gas on hydrophilic/hydrophobic electrode surface in aqueous solution and molten salt are also studies. They are compared to 1-G experiments in order to newly enlighten the matured gas electrode concepts. “Electrochemical Laboratory in ISS & Gateway” should be constructed with Space Agencies.
Identifying and Overcoming Rate-Limiting Steps for Nitrogen Fertilizer Production from Urine
Authors: Liu Matthew Junjie , Tarpeh William Abraham
Published: February 2020

Wastewaters containing nitrogen have a deleterious impact when discharged to the environment. Conventional nitrogen removal techniques are resource-intensive and limited to settings with formal sewer infrastructures. Furthermore, these techniques treat nitrogen as an impurity to remove rather than a resource to recover. In 2018, we addressed all three of these issues by demonstrating a proof-of-concept for electrochemical stripping (ECS) of ammonium sulfate from source-separated urine. ECS does not require caustic chemicals, can be implemented in remote settings, and recovers the fertilizer ammonium sulfate. In 24 hours, our ECS setup achieved 93% nitrogen recovery. Our next step is to improve the time-efficiency of ECS, but because it is a novel technology, we lack guidance in the literature for optimal experimental ranges. To grasp a more mechanistic understanding of the steps bottlenecking nitrogen recovery, we develop a model as follows. First, we decompose nitrogen recovery into major transport and chemical transformation steps. Experimental data is then fit to the model with a goodness of fit test. Using these fitted values as a starting point, we perform sensitivity analyses for each major step in order to elucidate what parameters most crucially govern nitrogen recovery. Preliminary results (attached) suggest that ammonia volatilization contributes nontrivial nitrogen losses to the system. Our model will guide further developments of ECS technology by providing quantitative measures of how to overcome rate-limiting steps in nitrogen recovery.

Figure 1
Next Generation Materials for Lithium-Ion Space Batteries
Authors: Deroy Chad , Dobley Arthur , Gitzendanner Rob , Morrison Eric
Published: February 2020

EaglePicher has been supplying batteries for energy storage for satellites and other space applications since 1958. These batteries have achieved over 2.6 billion hours of cell operations with no failures in orbit. Over the decades the battery chemistry has changed amongst various chemistries with some overlap and some still being used today. Typical space battery chemistries include: silver-zinc, nickel-hydrogen, nickel-cadmium, and then lithium-ion. Even within the lithium-ion chemistry the formulations and packaging has evolved over time and continues to change.

Lithium-ion space batteries continue to evolve today. New satellites and space applications are demanding increased energy, more power, and smaller volumes. This has led to improvements in increased energy, wider operating temperatures, more power and smaller packages. Every change in battery performance requires new or modified battery materials. For increased energy the incumbent cathode material for lithium-ion batteries is Lithiated Nickel Cobalt Oxide (NCO). This was changed to the Lithiated Nickel Cobalt Aluminum Oxide to increase the energy and improve cycle life. For wider operating temperatures the electrolyte formulation has evolved with new components and additives. Newer and next generation satellites are carrying state of the art instruments that demand high power or pulses of power. New lithium-ion battery chemistries have been developed to supply very high power discharges to supply the large currents. As small satellites are increasing in popularity, there is a push for smaller battery packs. This has led to a decrease in cell capacity and the introduction of commercial of the shelf (COTS) cells. These are often cylindrical in shape and typically 18650 in size. Transitioning to COTS cells has increased the ability to create modular space batteries, but has brought up new concerns on quality and reliability.

Quality and reliability, plus safety, are top concerns for space batteries. Replacement of batteries in space is extremely difficult and expensive. As each of the next generation battery materials are developed, reliability and safety much be eminent. These materials and batteries are often expected to supply power for decades. The continued testing, evaluation and analysis of the new chemistries and designs provides assurances for long-term performance and reliability. As these batteries have the potential to power satellites, landers, rovers, capsules, and habitats, EaglePicher continues to develop, evolve, demonstrate, and produce new battery chemistries and designs to meet the mission requirements.

Acknowledgements

We would like to thank: NASA JPL, Lockheed Martin and the Unites States Government for supporting some of this effort, and many of the EaglePicher employees who worked on these projects.
Development of an Electrochemical Oxygen Compressor and Generator for Spacesuit Oxygen Resupply
Authors: Graf John , Taylor Dale , Alvare Javier , Singh Prabhakar
Published: February 2020

NASA is sponsoring the development of an electrochemical method of supplying high pressure, high purity oxygen suitable for recharging spacesuit tanks during an exploration mission. The system is referred to as the Electrochemical Oxygen Generator and Compressor (eCOG-C). The method uses a ceramic oxygen transport membrane, with internal process airflow channels, and an electrochemical configuration that electrochemically pumps oxygen from the process air to the external environment. The oxygen transport membrane is placed inside a thermally insulated pressure vessel, allowing the oxygen to accumulate and pressurize. Except for a simple process air blower, the device is solid state. An alternate version of this process has demonstrated the ability to produce high purity (>99.99%) oxygen from ambient air. This version is intended to produce high pressure oxygen, the design goal is >4000 psig delivery pressure. This paper describes the NASA application, and the electrochemical systems found in the ceramic oxygen transport membrane. This project is in an early stage of development, a feasibility assessment has been completed, and the first iteration of prototyping is underway. There are three areas of emphasis in the initial prototyping effort: 1) developing interconnecting seals that join two different wafers with sufficient bond strength to sustainably withstand pressure forces, 2) developing interconnecting seals that join two different wafers with well matched coefficients of thermal expansion (CTE), to minimize thermal stress in the cell stack, 3) developing a ceramic transport membrane wafer with internal process air flow channels.

Figure 1
Regenerative Solid Oxide Fuel Cells for Venus Interior Probe Energy Storage
Authors: Stariha Sarah A. , Billings Keith J. , Jones John-Paul , Bugga R.
Published: February 2020

A novel variable altitude Venus interior probe is currently under development that uses in-situ power and propulsion to lower a balloon down into Venus’s atmosphere, approximately 20 km from the surface, and then bring it back up above the clouds and hover at approximately 60 km from the surface. One of the biggest challenges is finding an energy storage solution that can withstand Venus’s harsh atmosphere. At 20 km the probe will experience temperatures close to 325°C, pressures around 20 atm, and an atmosphere composed of CO2, with trace amounts of sulfur containing compounds. Conventional energy storage technologies, like batteries, are not an option under these conditions. The only technology that can survive under these conditions are solid oxide fuel cells (SOFCs), which operate in a temperature range between 600 – 1000 °C.

Fuel cells are devices that convert chemical energy, in this case from hydrogen and oxygen, into electricity with the only byproducts being heat and water. Solid oxide fuel cells can be run reversibly as an electrolyzer, taking the byproduct water and splitting it into hydrogen and oxygen that can then be used to run the fuel cell. A regenerative fuel cell system may therefore be built around a single SOFC stack. The goal is to run the SOFC to power the probe at 20 km and then reverse the SOFC to an electrolyzer when the probe is back above the clouds and use solar power to produce hydrogen and oxygen.

The data presented in this work shows the successful operation of a regenerative SOFC. Figure 1A shows a SOFC that was run in H2/O2 as an electrolyzer. Figure 1B shows a SOFC run as a fuel cell in different conditions including H2/O2 (red line) and H2/Air at different flow rates (blue lines). The goal of this work is to pinpoint the exact conditions a SOFC would need to operate at in order to successfully store energy for an interior probe in the Venus atmosphere.

This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) and NASA’s Innovative Concepts (NIAC) Program: “Venus Interior Probe Using In-situ Power and Propulsion (VIP-INSPR).

Figure 1
Johnson Thermo-Electrochemical Converter for Space Exploration
Authors: Johnson Lonnie , Campbell Tedric
Published: February 2020

Spacecraft are often required to operate in the outer reaches of the solar system and beyond where sunlight is very faint. Nuclear Power Systems (NPS), which includes both Radioisotope Power Systems (RPSs) and Fission Power Systems (FPS, Nuclear Reactors), are the only available power sources that can operate without constraints in these environments for the long periods of time needed to accomplish many missions. Efficient heat to electric conversion technology is needed to provide more power from significantly smaller and lighter weight sources that use less Pu238 and that require less structure for mechanical support and thermal management.

The Johnson-Thermo-Electrochemical Converter (JTEC) is a solid-state heat engine that has the potential for converting NPS heat into electricity at net efficiency levels as high 30 to 40% net, 70 to 80% of Carnot based on typical RPS heat source operating temperatures. Over the past five decades, conventional thermoelectric converters (Seebeck) have not been able to exceed 15% of Carnot (6% to 8% net). As a more efficient replacement for existing thermoelectric technology, JTEC will provide NASA with an attractive alternative for addressing the ever present need to minimize the amount of mass that must be delivered to space using expensive launch vehicles. A laboratory proof-of-concept demonstration has been successfully completed and an initial application analysis has been performed to understand the technology and its potential impacts at maturity. JTEC represents an opportunity to develop common technology that feeds both FPS and RPS and, thereby, support a full spectrum of space power requirements.
A Cell Selection Method and Validation Process for the Aerospace Battery
Authors: Chung Jaesik , Jung Kwang , Darcy Eric C. , Russell Samuel P.
Published: February 2020

This paper studied a cell selection method and its validation process for the aerospace battery. A cell selection method includes visual inspection, mass and dimension check, electrical tests (OCV, CCV, AC Impedance), capacity measurement and soft-short test. The 6-sigma concept was adopted on data analysis of the cell selection. All the cells outside of the 3-sigma level were rejected, and accepted cells were selected for the validation testing. The validation process executes cycle testing of the four types of 4S string battery group according to the mission operating conditions of the Human-spaceflight followed by analysis of the battery capacity during the cycle and by analysis of non-destructive and DPA (destructive physical analysis) of the cells. The effectiveness of each item on the cell selection method was identified and discussed by non-destructive and DPA analysis with some electron microscope analysis. This paper recommends this proven selection method and validation process for the future aerospace battery.
Aptamer-Modified Microelectrodes for the Electrochemical Impedance Spectroscopy Detection of Neuropeptide Y
Authors: López Luis F , Hernandez Nerika G , Flores Krystal , Cruz John , Cunci Perez Lisandro
Published: February 2020

The design novel biosensors is a broad field including a wide range of applications including medical diagnostics and environmental monitoring. Small sizes of the electrodes have advantages used for selective identification of a biological target, such as voltammetric time scales, lower background noise and higher spatial resolution. Platinum and Carbon nanofiber has been some promising materials for fabrication of electrodes because of their electrical conductivity, chemical stability and high surface area. The intended application is to the possibility to create point of care diagnostics for monitoring the health of astronauts. Neuropeptides are short amino acid chains that are synthesized in the soma and dendrites, and they are stored in large dense core vesicles until released from nerve endings as well as from dendrites. Also, it’s not recycled and there is no reuptake system, but they are broken by peptidases, which require the cell to always synthesize new molecules to replace them by sending them from the soma to the nerve endings and dendrites. Other small neurotransmitters are normally released together with neuropeptides; therefore, it is essential to develop a technique for their detection as selective as possible and to have a strategy to cancel out the signal exerted by other neurotransmitters. The structural similarity between neuropeptides makes their detection impossible using common electrochemical techniques. Their study is currently done measuring the expression of neuropeptides in-vitro or using microdialysis coupled with mass spectrometry, which gives temporal resolution of tens of minutes. In this project, we have developed a modification protocol that reproducibly adds highly selective aptamers to the microelectrodes and the adsorption of neuropeptide Y differentially detected using microelectrodes. Based on the results, changes in concentration due to the release and absorption of neuropeptide Y can be followed with continuous electrochemical impedance measurements using microelectrodes, with the specificity provided by the used of aptamers in the surface of the microelectrodes.
A Glucose Microfluidic Sensor Tested in Artificial Microgravity
Authors: López-González Berenice , Estrada-Solís Martín de Jesús , Lavan David A , Cuevas-Muñiz Francisco Mherande
Published: February 2020

A microfluidic device for the detection of glucose in artificial microgravity was tested, in order to study the behavior of an electrochemical system in these conditions. The electrochemical device was designed by computational simulation, and was constructed in PMMA by the computer numerical control machine. The device consisted of a V-shaped microfluidical channel with an inlet and an output. CuPt was electrodeposited on glassy carbon, and used as electrode sensor for glucose, Ag/GC was used as reference electrode, and Pt/GC as counterelectrode. The device was tested in earth conditions and microgravity conditions (10-7 G). Microgravity was simulated in a three-axis random position machine constructed in the INICTEL-UNI (Lima, Peru). Voltammetry studies (-100 mV to 400 mV vs. Ag pseudo reference) was performed with a remote controlled potentiostat, placed in the machine, the test were carried out in glucose solution 5 mM in PBS 7.4, and with blood. A current asociated to the glucose was observed in glucose and blood, meanwhile in the blank (PBS 7.4) this current was absent. This result opens possibility of testing glucose in microgravity conditions.
Capillary Electrophoresis and Contactless Conductivity Detection: A Powerful Tool for in Situ Analysis of Samples from Ocean Worlds
Authors: Ferreira Santos Mauro Sergio , Jaramillo Elizabeth A , Noell Aaron C , Mora Maria Fernanda
Published: February 2020

The search for life in our Solar System is one of the highest priorities at NASA. Because of the presence of liquid water in the Oceans Worlds such as Jupiter's moon Europa, and Saturn's moon Enceladus, these bodies could potentially harbor life and be the focus of future missions. Liquid-based analytical techniques are particularly attractive for in situ analyses on these locations, since the sample could be analyzed in its natural state (e.g., liquid water or melted ice). Capillary electrophoresis (CE) is a powerful liquid separation technique that has tremendous promise for in situ studies on Ocean Worlds. By using contactless conductivity detection (C4D) a wide number of charged species (both organic and inorganic) can be detected without the need of derivatization. This includes amino acids, which are powerful biosignatures in the search for life beyond Earth as well as inorganic salts that are of primary importance to biological activity and they also determine the thermo-physical properties of any liquid mixture. The characterization of the distribution of inorganic ions is essential to assess the habitability of an extraterrestrial environment and provide sample context for trace detection of amino acids. We are currently developing CE-C4D methods that would be suitable for flight implementation. The first method allows the simultaneous analysis of inorganic cations and amino acids relevant to astrobiology [1]. A second method for analysis of inorganic anions and organic acids is also being developed. The main goal is to use both methods with a single capillary in order to obtain detailed chemical composition of the sample with the simplest configuration possible. Standard mixtures including some of the most relevant analytes for planetary studies were selected and electropherograms for the separations of the positively and negatively charged analytes are presented in the Figure 1A and B, respectively. To demonstrate the potential applications of these methods we have analyzed relevant natural samples of varying salinity.

Acknowledgments

The research described in this abstract was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Financial support for this project was provided by The Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Program.

References

[1] Ferreira Santos, M. S. et al., Electrophoresis 2018, 22, 2890-2897.

Figure 1
All-Printed Triboelectric Nanogenerator (TENG) for Nasa's in-Space Manufacturing Program
Authors: Seol Myeonglok , Meyyappan M. , Han Jin-woo
Published: February 2020

Most of the small sensors on a chip such as gas and biosensors require only mW level of power. This level of power can be easily scavenged from motions and vibrations, thus creating self-powered sensors. Tribolelectric nanogenerator (TENG) is an energy-harvesting device that converts the external mechanical energy (such as wind and any other motion/vibration) into electricity by a conjunction of triboelectric effect and electrostatic induction through rubbing two sheets of materials. A potential is created by the triboelectric effect due to the charge transfer between two thin organic/inorganic films that exhibit opposite tribo-polarity. Electrons are driven to flow between two electrodes attached on the backsides of the films in order to balance the potential. There has been a lot of work in the last five years on TENG development and energy generation mechanism. We have developed an all-printed TENG system in support of our In Space Manufacturing program that aims to print devices on demand in the International Space Station. This talk will discuss the selection of electrode materials, construction of TENG and output performance. This work was supported by the NASA In Space Manufacturing program.
Lithium Plating Patterns on Lithium Anode Revealed with Operando Nanoscale X-Ray Imaging
Authors: Parimalam Bharathy , Li Yubai , Choi Paul , Litster Shawn
Published: February 2020

Next generation high-energy-density battery systems need alternatives to graphite-based intercalation anodes that have insufficient energy density for wide-spread vehicle electrification. The lithium metal anode is an attractive alternative, however it is plagued with dendrite growth, and poor Coulombic efficiency. Significant improvements have been made in safety and electrochemical performance of the lithium anodes recently through modified electrolyte chemistry and protective layers. Despite the apparent improvements in the electrochemical performance, postmortem/ ex-situ analyses bring limited understanding of the underlying mechanisms that generate the deposition morphology and growth patterns.

Here, we will present on an X-ray transparent coin cell configuration we have developed for operando imaging and 3D imaging in nano-scale resolution X-ray microscopes. We use nano-resolution x-ray computed tomography (nano-CT) and the X-ray transparent coin cell to directly observe the electrochemical deposition on lithium anodes as a function of time. Lithium electrodepositions in different electrolyte formulations reveal drastically different nucleation and deposition growth mechanisms that could not be revealed by inspecting post-mortem structures. We will present and discuss operando 2D & in-situ 3D images of lithium electrodeposition under varying parameters and electrolyte chemistry.

This material is based upon work supported by the US Office of Naval Research for the battery safety studies under grant N00173-17-1-G009. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research.