Next Generation Analytical Tools to Boost Energy Efficiency

Introduction

The rate at which the world consumes energy is increasing. Stores of chemical energy such as oil and gas, broadly referred to as fuels, remain one of the primary energy sources for today’s world. The versatility, reliability and portability of fuel has made it indispensable to the modern world.

In order to meet the future energy demands of our planet, research into fuel and alternative energy sources will be critical. Pittcon 2019 will feature a symposium on current developments in energy research with a focus on fuel. This article will introduce some of the topics, researchers and recent breakthroughs that will be showcased at Pittcon 2019.

Chemical fuel is one of the most widely used energy sources in the world. Liquid fuels are easily transportable, have very high energy densities, and occur naturally with relatively low requirements for processing.

The energy density of chemical fuels is surpassed only by nuclear energy stores; however, nuclear energy comes with significant risks and expense, in addition to the difficulty associated with converting nuclear energy into useful work, all of which limit the use of this type of power. In contrast, chemical fuel is relatively safe and straightforward to use. An added benefit of chemical fuels is that they occur naturally – although, as noted by many of the speakers at Pittcon 2019, the widely-held belief that chemical fuel is a “natural resource” is changing.

The high energy density of fuel means that alternatives such as batteries or mechanical energy stores are only preferred in very niche applications. The energy per unit mass of gasoline is around 25 times higher than that of lithium metal batteries, making it indispensable to transport and manufacturing. As a result, almost 100 million barrels of gasoline are consumed globally every day.

Gasoline, diesel and other petroleum products are largely derived from naturally occurring and oil deposits. Like many natural fuels, natural oil is non-renewable. A frequently cited statistical review from BP in 2014 estimated that there were 53 years’ worth of oil remaining on the planet if rates of consumption remained the same. Despite this, oil use has increased every year since the estimate was published.

It should be noted that this estimate relied heavily on proven oil reserves and there is likely more oil available in the world than the report indicates.

Oil is a rapidly dwindling resource, and it is clear that the world’s fuel industry will need to undergo drastic changes in coming years. The rapid depletion of natural fuel deposits means that research into alternative fuel sources is crucial if we are to continue to meet global demand for energy.

Additionally, environmental issues resulting from global reliance on fossil fuels are worsening. The cumulative environmental impacts of traditional hydrocarbon fuel sources such as crude oil and natural gas are undeniable: Average global temperatures are increasing, and CO­₂ and CH₄ emissions resulting from fossil fuel are contributing to this problem. Research into sustainable energy sources will play an  important role in combating these increases.

Research focused on changes to the fuel industry can be broadly categorized into three areas: sustainable energy sources, analysis, and storage. Clearly there is a need for new, sustainable forms of fuel. Once these are identified and sourced, scientists will require analytical tools in order to characterize, optimize and integrate them into our existing fuel infrastructure. Finally, we must investigate alternative forms of energy storage, such as electrochemical fuels, in order to facilitate the widespread use of other renewables like solar and tidal energy.

This article provides a review of the recent advances in analytical tools, energy storage and sustainability systems to be presented at Pittcon 2019.

Biodiesel as a sustainable fuel

Biodiesel is one area in which these fields of research are coming to fruition. Biodiesel is a renewable fuel derived from feedstocks such as vegetable and animal fat and recycled cooking oils. These fats and oils undergo esterification with the addition of alcohols to produce long chain mono-alkane esters, commonly referred to as fatty acid methyl esters (FAME), and relatively small amounts of glycerin, a naturally-occurring sugar.

Biodiesel offers many advantages: it’s renewable, producible on a domestic level from agricultural or recycled resources, and emits much less greenhouse gas than conventional diesel. Importantly, it can be used in new and existing diesel equipment with no or minor modifications; making it an ideal candidate to displace petroleum-derived diesel.⁶

The use of biodiesel as a blending component in diesel fuels is already significant and expected to increase. But there remain challenges with quantitative chemical analysis of biodiesel and renewable diesel fuels and the potential impact of their various components.

Biodiesel expert Teresa Alleman of the National Renewable Energy Laboratory will be speaking at Pittcon 2019 on all aspects of biodiesel research, including analysis, storage and sustainability, in a presentation entitled “Analytical Challenges in Alternative Fuel Quality Evaluation”.

References

• Key world energy statistics – International Energy Agency 2017.
• Meeting the Needs of Portable Electronic Devices : Lithium Ion Batteries. 6–8 (1999).
• Fossil and Alternative Fuels – Energy Content. Available at: https://www.engineeringtoolbox.com/fossil-fuels-energy-content-d_1298.html. (Accessed: 3rd March 2019)
• BP Statistical Review 2018.
• Global Temperature | Vital Signs – Climate Change: Vital Signs of the Planet. Available at: https://climate.nasa.gov/vital-signs/global-temperature/. (Accessed: 4th March 2019)
• Alleman, T. L. et al. Biodiesel Handling and Use Guide (Fifth Edition). (2016).
• Christensen, E. D., Alleman, T. & McCormick, R. L. Re-additization of commercial biodiesel blends during long-term storage. Fuel Process. Technol. 177, 56–65 (2018).
• Michael J. Haas, *,†, Karen M. Scott, †, Teresa L. Alleman, ‡,§ and & Robert L. McCormick‡, §. Engine Performance of Biodiesel Fuel Prepared from Soybean Soapstock:  A High Quality Renewable Fuel Produced from a Waste Feedstock‖. (2001). doi:10.1021/EF010051X
• McAlpin, C. R., Voorhees, K. J., Alleman, T. L. & McCormick, R. L. Ternary Matrix for the Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI–TOF MS) Analysis of Non-fuel Lipid Components in Biodiesel. Energy & Fuels 25, 5407–5415 (2011).

Chapter 1 – Tapping into Microbiological Pathways for Renewable Energy

Pittcon 2019 will be holding a symposium entitled “The Application of Analytical Chemistry in Biofuel Study”. Both speakers’ research involves the use of advanced analytical chemistry techniques to determine the underlying mechanisms of microbiological processes which have applications in renewable energy.

The role of microorganisms in the synthesis of biofuels is a very active area of research, bringing together experts from biosciences, chemistry, physics and engineering. This chapter outlines recent research into the role of biosynthetic pathways for biofuel production; and some of the analytical methods used to overcome challenges in evaluating the conversion processes, quantifying production yield and providing specification of the biofuels.

Engineering Microbial Synthesis of Biofuel

Genetically modified bacteria are used to synthesize proteins and other organic molecules for human use, which has proven highly valuable in pharmaceutical production. The prospect of using genetically modified bacteria to synthesize biofuels instead is an attractive proposition and has been the subject of much research.

However, bioengineering bacteria to synthesize chemicals is a complex process. Replacing a single gene in a bacterial genome will not necessarily cause the bacterium to generate a high yield of an arbitrary compound: The many quirks of gene expression and epigenetics mean that the relationship between genome and cell functionality is incredibly complex and difficult to characterize. In order to effectively utilize microbiological pathways for biofuel production, scientists require detailed and quantitative tools for characterizing cell activity at a functional level.

The field of metabolomics aims to address these issues. Whereas genomics deals with DNA and proteomics deals with the proteins synthesized in, and modified by, a cell; genomics is further down this chain and deals with the complete set of metabolites within a cell. As such, metabolomics is systemically closer to biological phenotype than genomics, transcriptomics and proteomics; thus, gives a more meaningful picture of a cell’s functionality.

While the goal of metabolomics is to provide a complete, quantitative and holistic analysis of a given metabolome; this is not yet feasible due to the chemical complexity of the metabolome. Research has instead focused on the more manageable task of local metabolite profiling. Although this is a far cry from global metabolic profiling, the use of the latest analytical technologies to look at specific differences in metabolite levels in response to genetic modification are successfully being used to elucidate gene function and identify unknown metabolites.

Analyzing Biosynthetic Pathways via Chromatography and Mass Spectrometry

Analyzing metabolites is a challenge for analytical chemistry technology. Although Nuclear Magnetic Resonance (NMR) is capable of delivering high-throughput structural fingerprinting of chemical species; issues with cost, sensitivity and quantification must be addressed if it is to compete with mass-spectrometry-based (MS) approaches.

Similarly, array-based techniques such as nanostructure-initiator mass spectrometry (NIMS) are ideal for screening crude microbial extracts, but developments in nano-surface technology are essential if they are to be used for global metabolite profiling.

Metabolomics frequently utilizes a combination of fast chromatography for separation, followed by fast-scanning MS. Recent advances in 2-dimensional gas chromatography (GC) have led to a growing number of applications of GC-MS analysis in microbial metabolomics.

One drawback of GC-MS is that gas chromatography is only suitable for separation of volatile analytes, which often requires time-consuming derivatization of any non-volatile metabolites. Furthermore, temperature-sensitive compounds such as phosphorylated metabolites can degrade when exposed to high temperatures in a GC oven.

Fortunately, liquid chromatography offers a viable alternative. Rapid liquid chromatography (LC) separations are now routinely performed by ultra-high-performance LC (UHPLC) systems, and has demonstrated its ability to resolve large numbers of metabolites without any need for derivatization of non-volatile analytes.

Edward Baidoo of the Lawrence Berkeley National Laboratory will be speaking at Pittcon 2019 on analyzing and engineering microbial synthetic pathways for biofuel production. His talk, “Targeted Metabolomics – A Tool to Identify Bottlenecks in Microbial Biosynthetic Pathways”, will outline his work on the use of LC-MS for targeted metabolomics in order to understand the functional effects of microbial genome modification. Other work by Baidoo includes the modification of E. Coli metabolic pathways for biofuel synthesis.

Metabolic electron transfer in waste-to-energy applications

Certain microorganisms have developed electron transport mechanisms which may help develop waste-to energy technology or serve as a power source alone. For example, bacteria of the Shewanella genus produce electrically conductive nanowires to extend the reach of their metabolic pathways.

By exporting electrons along these nanowires to abiotic electron accepting surfaces, Shewanella are able to complete oxidative metabolic processes and survive in anoxic conditions. This process, known as extracellular electron transfer (EET) is being heavily pursued for applications in wiring microbes to electrodes in waste-to-energy applications. Other bacteria have been shown to carry out long distance electron transport across biofilms, which may lend them to applications in bacterial fuel cells.

At Pittcon 2019, Moh El-Naggar from the University of Southern California will be delivering a talk entitled “Life Electric: Microbial Electrochemical Systems for Energy and Environmental Applications”. The talk will focus on the use of biophysical measurements, electron transfer simulations, and electron cryo-tomographic studies of the cellular conduits that perform EET.

The Pittcon Expo will feature the latest in LC-MS, GC-MS and other separation/spectrometry technologies from world leading manufacturers including Teledyne ISCO and Thermo Fisher Scientific.

References

• Baidoo, E. E. K. & Keasling, J. D. Microbial metabolomics: welcome to the real world! Metabolomics 9, 755–756 (2013).
• Garcia, D. E. et al. Separation and mass spectrometry in microbial metabolomics. Opin. Microbiol. 11, 233–239 (2008).
• McKee, A. E. et al. Manipulation of the carbon storage regulator system for metabolite remodeling and biofuel production in Escherichia coli. Cell Fact. 11, 79 (2012).
• Stephen Koenig. Harnessing energy from living sources has potential for new sustainable technology. USC News Available at: https://news.usc.edu/139961/new-sustainable-energy-solution-bacterium/. (Accessed: 5th March 2019)
• Pirbadian, S. et al. Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components. doi:10.1073/pnas.1410551111
• Reguera, G. et al. Biofilm and Nanowire Production Leads to Increased Current in Geobacter sulfurreducens Fuel Cells. Environ. Microbiol. 72, 7345–7348 (2006).

Pittcon Tracks

Chapter 2 – Fuel for Thought: Improving Current Energy Sources

Global transport and manufacturing infrastructure is adapted and optimized for the use of hydrocarbon fuels, which are typically derived from naturally occurring petroleum. Use of waste products such as atmospheric carbon oxides and wastewater as a feedstock for synthesized hydrocarbon fuels offers two great benefits: It mitigates climate change by either sequestering atmospheric carbon or preventing other carbon waste products from entering the atmosphere. It also provides an energy-dense store for renewable energy that can be easily utilized in existing infrastructure without the need for adaptation. The latter factor is crucial in driving early adoption of renewable technologies. The drive to simultaneously reduce waste and increase renewable energy production capacity has fueled research into many different waste-to-energy resources, which will be explored in this chapter.

Wastewater as a Renewable Energy Source

Wastewater from municipal, agricultural and industrial sources is a valuable and underutilized source of renewable energy. Water utility providers are investing in techniques to recover this energy in order to improve the efficiency of their facilities and reduce costs to rate payers.

The first phase in wastewater treatment involves the removal of solid matter. This solid matter is largely organic material which can be anaerobically digested by microorganisms. Solid material is pre-treated via thermal hydrolysis. This process involves breaking up solid material at high temperature and pressure, which aids complete decomposition in the following digestion phase. Anaerobic digestion produces biogas, whose flammable components (primarily methane) can be combusted to provide energy for the water treatment facility itself. Additionally, the produced methane can be purified and compressed as a power source for other applications.

Zonetta English of Louisville MSD will be giving a talk entitled “Wastewater, A Renewable Energy Source” at this year’s Pittcon, covering her work in implementing technology to reclaim energy from wastewater in Louisville and the associated analytical techniques. English will also be introducing the Leaders Innovation Forum for Technology (LIFT), a central repository for innovation, research, and technology initiatives provided by the Water Research Foundation.

Wastewater analysis experts Astoria Pacific will be in attendance Pittcon 2019 to discuss their products and services and showcasing a range of ion/nutrient analyzers including the Astoria2 Analyzer. They will be joined by Teledyne ISCO who will be exhibiting a range of analytical technologies ​for water and wastewater analysis including the new LaserFlow™ Non-contact Velocity Sensor, which uses advanced Doppler technology for flow measurement.

Solar Fuels and Artificial Photosynthesis

The process of creating chemical fuels from atmospheric carbon oxides to store energy from renewable sources such as wind and solar has been compared to photosynthesis, as it emulates the way in which photosynthetic organisms store solar energy by synthesizing energy-dense carbon-based compounds from atmospheric CO₂. Such compounds are known as “solar fuels” and could constitute a renewable and less environmentally damaging alternative to fossil fuels.

Natural photosynthesis produces hydrocarbons and oxygen using sunlight, water and carbon dioxide from the atmosphere. Attempts to create artificial photosynthesis in these terms is currently an active area of research in biochemistry. Such technologies could be preferable to conventional solar cells, as the energy produced is directly stored in an energy-dense and ready-to-use chemical form without the need for batteries.

Natural photosynthesis can be divided into three steps: Firstly, light-harvesting complexes absorb solar radiation and use the energy to produce free electrons, the start of the photosynthetic chain. Secondly, these electrons undergo proton-coupled transport along a chain of cofactors, creating an energy gradient in the form of local charge separation. Finally, redox catalysis occurs, using the aforementioned transferred electrons to oxidize water to O₂ and protons. These protons can then, in some species, be used for production of H₂.

Each of these processes requires the use of one or more catalysts which are efficient enough to effectively use the energy available in solar radiation. Design and synthesis of efficient catalysts for artificial photosynthesis is the subject of ongoing research. Consequently, detailed analysis of catalyst dynamics is crucial in order design effective artificial photosynthetic systems.

Electrochemical measurements can, with the aid of simulation, provide an outline of redox reactions within a system, although the detail available depends on system complexity and the relative rates of reaction. Combining electrochemical measurements with spectroscopic investigation can provide far greater insight into the structure and activity of shorter-lived chemical species in-situ, making them ideally suited to the characterization of electrogenerated intermediates such as those involved in (artificial) photosynthesis. Specifically, Infrared Spectroelectrochemistry (IRSEC) can be used to identify bonding changes due to redox-linked protonation/deprotonation of specific sites in molecules during the proton coupled electron transport (PCET) process.

Charles W Machan of the University of Virginia will be delivering a talk entitled “Improving the Activity of Molecular Electrocatalysts for Reactions Relevant to Solar Fuels” at Pittcon 2019. This talk will describe ongoing work in developing new catalysts for processes in artificial photosynthesis, with a focus on the detailed analytical techniques and technologies (including IRSEC) that make this possible.

Many companies specializing in detailed functional chemical analysis will be onsite at Pittcon 2019. Analytical chemistry experts Shimazu and Thermo Fisher will both be exhibiting a range of IR spectroscopy tools, including a range of FTIR systems and accessories.

References

• Turning Wastewater into Renewable Energy – AZo Cleantech. Available at: https://www.azocleantech.com/article.aspx?ArticleID=845. (Accessed: 6th March 2019)
• Water Analysis | Astoria-Pacific. Available at: http://www.astoria-pacific.com/industrial/product-applications/water/. (Accessed: 6th March 2019)
• LaserFlow Non-contact Velocity Sensor. Available at: https://www.teledyneisco.com/en-us/water-and-wastewater/laserflow. (Accessed: 6th March 2019)
• Best, S. P., Borg, S. J. & Vincent, K. A. Infrared Spectroelectrochemistry. Techniques (2008).
• Huynh, M. T. et al. Concerted One-Electron Two-Proton Transfer Processes in Models Inspired by the Tyr-His Couple of Photosystem II. ACS Cent. Sci. 3, 372–380 (2017).
• FTIR Spectroscopy | SHIMADZU EUROPA. Available at: https://www.shimadzu.co.uk/ftir-spectroscopy?pk_campaign=adwords-thermo&pk_kwd=thermo-ftir-em&pk_campaign=1002686109&pk_kwd=thermo ftir. (Accessed: 7th March 2019)
• Fourier Transform Infrared (FTIR) Spectroscopy – Thermo Fisher. Available at: https://www.thermofisher.com/uk/en/home/industrial/spectroscopy-elemental-isotope-analysis/molecular-spectroscopy/fourier-transform-infrared-ftir-spectroscopy.html. (Accessed: 7th March 2019)

Chapter 3 – Advances in Oil Analysis

While the development of renewable fuels is of critical importance, crude oil remains the world’s primary source of petroleum fuels used by existing technology. Advancements in oil analysis technologies, discussed in this chapter, are necessary both for the characterization of petroleum fuels and for petroleum forensic techniques used to identify environmental oil spills and leaks.

Crude oil is a complex mixture of hydrocarbons; non-hydrocarbon organic compounds containing Nitrogen, Sulphur and Oxygen; and organometallic compounds. The refinery process splits crude oil into different fractions such as naphtha, used for production of gasoline, and kerosene which is used for jet fuel. Different crude oil fractions require different analytical tools and methods for analysis.

Typically, oil analyses are based on gas chromatography (GC) techniques. Standalone GC with conventional detectors is often sufficient for saturated fractions. However, these systems are limited to analysis of hydrocarbons with carbon numbers less than 35 because its lower temperature limit is about 325C and thus incapable of volatilizing heavier compounds. Analysis of heavier hydrocarbons requires high temperature GC.

Aromatic compounds are difficult to analyze using stand-alone GC, so often a combination of gas spectrometry and mass spectrometry (GC-MS) is used to increase sensitivity. Heavier petrochemical products like resins and asphaltenes have higher boiling points and can be analyzed by liquid chromatography and mass spectrometry (LC-MS).

Comprehensive Two-Dimensional Gas Chromatography and Time of Flight Mass Spectrometry for Petroleum Characterization

The level of detail provided by GC can be enhanced by the use of comprehensive two-dimensional gas chromatography (GCxGC). This technique involves two GC columns, where effluent from the first column is trapped and injected into a second column. This technique greatly improves peak resolution compared to single-column GC, enabling the identification of more compounds. By using different stationary phases in each column, analytes can be separated according to different physiochemical properties in each column, giving a two-dimensional analysis. Early adoption of GCxGC by the petrochemical industry enabled the identification of large numbers of hydrocarbons and isomers in oil samples.

Analytical techniques such as these are valuable to petroleum forensics, the detection and characterization of environmental petroleum products, where they can aid point-source detection of petroleum product leaks from sources such as hydraulic fracturing (“fracking”) operations. Such oil extraction methods necessitate the development of these forensic technologies so that environmental impact can be monitored and minimized.

Christina N Kelly of LECO corporation will be giving a talk entitled “Case Studies in Oil Spill Forensics: Finding Petroleum Biomarkers with GCxGC-TOFMS” at Pittcon 2019. The talk will cover work on hydrocarbon fingerprinting using a combination of GCxGC and high-resolution time-of-flight mass spectrometry.

Global analytics specialists LECO will be showcasing a range of technologies for oil analysis at Pittcon Expo 2019, including the FLUX™ GCxGC Flow Modulator for straightforward and cost-effective implementation of GCxGC. Analytical instrument manufacturer VICI will also be exhibiting a range of high-performance gas chromatography equipment including column heaters and fast temperature programmers.

Analyzing Fuel with Gas Chromatography and Vacuum Ultraviolet Technology

Other methods for the separation and speciation of hydrocarbons in gasoline-range fuel analysis include detailed hydrocarbon analysis (DHA) and multidimensional gas chromatography (MDGC). DHA uses a long (typically 100m) chromatography column for the characterization of individual components as well as bulk characterization of a sample. MDGC involves the use of two or more GC columns to achieve analyte separation in multiple dimensions, in the same manner as GCxGC.

However, while these techniques can provide very accurate results, analytical methodologies must be easy to perform and cost-effective in order to maximize their use in the petroleum industry. Issues with cycle time and setup complexity in DHA and MDGC have driven research into alternative techniques for the characterization of compounds in oil and fuel samples.

Gas chromatography – vacuum ultraviolet (GC-VUV) is an alternative to these techniques, designed to minimize complexity and speed up analysis. GC-VUV uses a single 30m polydimethylsiloxane GC column and employs vacuum ultraviolet absorption spectroscopy to yield carbon number breakdown and compound speciation in gasoline-range samples. Since DHA requires pre-column ‘tuning’ and MDGC involves an often-complicated series of valves and traps, GC-VUV offers a simpler alternative. In addition, GC-VUV offers shorter run times – the method typically takes 15-30 minutes, compared to 3 hours for DHA and 1 hour for MDGC.

James A Diekmann of VUV Analytics will be speaking about the advantages of GC-VUV technology at Pittcon 2019 in a talk entitled “Recent Advances in the Analysis of Petroleum-based Fuels Using Gas Chromatography-Vacuum Ultraviolet Spectroscopy”.

A number of world-leading providers of analytical technologies and services to the petrochemical industry will be attending the Pittcon Expo 2019. These include VUV Technologies, who will be exhibiting their range of analytical technology for UV detection and processing at the Pittcon Expo 2019. AMETEK Petrolab Company will also be showcasing their range of sophisticated automated testers for petrochemical analysis.

References

• Petroleum Testing Information – Thermo Fisher. Available at: https://www.thermofisher.com/uk/en/home/industrial/manufacturing-processing/manufacturing-processing-learning-center/power-energy-information/oil-gas-information/petroleum-testing-information.html. (Accessed: 7th March 2019)
• Murphy, B. L. & Morrison, R. D. Introduction to environmental forensics.
• What is GCxGC? : SHIMADZU (Shimadzu Corporation). Available at: https://www.shimadzu.com/an/gcms/gcgc-2.html. (Accessed: 7th March 2019)
• Piotrowski, P. K. et al. Elucidating Environmental Fingerprinting Mechanisms of Unconventional Gas Development through Hydrocarbon Analysis. Chem. 90, 5466–5473 (2018).
• Flux GCxGC Flow Modulator. Available at: https://www.leco.com/flux-gcxgc-flow-modulator. (Accessed: 7th March 2019)
• VICI Fast GC Components. Available at: https://www.vici.com/gc/fast_gc.php. (Accessed: 7th March 2019)
• Detailed hydrocarbon analysis. Available at: https://theanalyticalscientist.com/app-notes/detailed-hydrocarbon-analysis. (Accessed: 7th March 2019)
• Cochran, J., Diekmann, J., Wispinski, D. & Walsh, P. Determination of Hydrocarbon Group Types and Select Hydrocarbons in Gasoline in Less than 15 Minutes Using Gas Chromatography-Vacuum Ultraviolet Spectroscopy.
• GC Detector Products by VUV Analytics | VUV Analytics. Available at: https://vuvanalytics.com/products/. (Accessed: 7th March 2019)

Chapter 4 – Energy Storage Solutions: Making Power Last Longer

Energy storage is one of the great challenges that must be addressed in order to meet energy requirements in the future. In order to transition to renewable energy sources like wind and solar power, efficient and cost-effective means of storing this energy must be found.

The automobile industry and transport industry as a whole are often the target of this research, due to their high rate of energy consumption and requirement for particularly energy-dense power sources. Transport of passengers and goods accounts for approximately 25% of global energy consumption. Consequently, energy storage technologies must meet the stringent requirements of the transport sector in order to be commercially viable. The US Department of Energy (DOE) has set the goal of developing a battery capable of storing 300Wh/L volumetrically, and 250Wh/kg by mass, in order to enable the realization of a mid-sized sedan with a range of 300 miles. Li-ion batteries have been the prime candidates, enjoying success in the consumer electronics market, although applications in the automobile industry has proven to be much more challenging.

The creation of a practical, versatile and commercially viable energy storage technology hinges on the development of new high-capacity materials.

Understanding Energy Storage Materials

The primary indicators of energy storage device performance such as energy density, catalytic activity, cycle life and stability are easily determined via electrochemical methods. However, the more complex behavior that govern a given material’s electrochemical behavior can be more difficult to determine. Elucidation of these processes is crucial for the development of high-performance energy storage technology.

The issue of examining electrochemical processes in energy storage devices is complicated by the fact that their material properties generally change when in operation compared to open-circuit measurements. This makes ex-situ characterization methods unreliable for a true understanding of the processes involved in their function. This is particularly important for metal-oxide-based electrode materials, which are known to undergo complex phase-changing redox reactions during operation. For this reason, it is necessary to develop coupled operando electrochemical methods which implement electrochemical cells into advanced characterization techniques.

X-ray methods such as scanning transmission X-ray microscopy (STXM) and X-ray diffraction (XRD) have been successfully used to provide spatially resolved information about local phase, electronic and physical states, including oxidation states, of electrocatalysts in operando. These techniques have also provided insight into the activity and alkaline water-splitting electrocatalysts, with applications in solar fuel development.

Additionally, coupled electrochemical-atomic force microscopy (EC-AFM) has been used to explore the relationship between activity and stability for water splitting electrocatalysts. EC-AFM is a modification of classical AFM whereby morphological and electrochemical measurements can be taken simultaneously; enabling the investigation of electrode surface morphology during electrochemical processes.

Pittcon 2019 will be welcoming Tyler J Mefford of Stanford University, who will be delivering a Contributed Organized Session entitled “Operando Electrochemical Methods for Studying Energy Storage and Conversion Materials in Action”. The session will cover his work in the analysis of electrochemical behavior in transition metal oxides using STXM, XRD and EC-AFM.

World-renowned manufacturer of high-performance scientific instruments and analytical solutions Bruker will be at Pittcon 2019, showcasing their top-of-the-line XRD and EC-AFM systems. These include the D8 DISCOVER family of XRD platforms which are among the most accurate, powerful and flexible on the market. Bruker will also be presenting their EC-AFM system for real-time visualization of electrochemical reactions, designed specifically to handle Li battery research.

Designing Materials for High Rate Energy Storage

Although energy density is frequently the key performance metric of energy storage technology, charge rate and cycle life remain crucial factors for certain applications in modern technology. Electrochemical capacitors can be charged in much shorter time frames than batteries, typically seconds to minutes, however they store 1–2 orders of magnitude less energy. As a result, research into materials with energy density comparable to batteries and cycle lives comparable to double-layer or electrochemical capacitors is an active area of research.

These devices could offer charge rates far beyond that of conventional electrical storage media, with applications including consumer electronics, rapid-charging electric vehicles, and sustainable energy storage. Recent research indicates the importance of developing new materials which enable electron transfer and ionic transport with multi-electron redox chemistries in order to realize these devices.

Progress in this area has been made using Li+ ion insertion in Nb₂O₅ as a model system in which to achieve high rate energy storage. This material exhibits a property termed intercalation pseudocapacitance, wherein the crystalline network offers two-dimensional transport pathways with no limitations on solid-state diffusion. This results in a material with electrochemical characteristics similar to a double-layer capacitor but with high levels of energy storage due to the occurring redox reactions.

Bruce Dunn of the University of California will be speaking about his work on the development of Nb₂O₅ as an energy storage material at Pittcon 2019 in a talk entitled “The Design of Materials for High Rate Energy Storage”. The results of this work may lead to materials and devices which offer both high energy density and rapid rates of energy transfer.

References

• Products | AMETEK Petrolab Company. Available at: https://www.petrolab.com/products. (Accessed: 7th March 2019)
• Transportation sector energy consumption Figure 8-1. Delivered transportation energy consumption by country grouping, 2012-40 (quadrillion Btu).
• International Energy Outlook 2016 | U.S. Energy Information Administration. Available at: https://web.archive.org/web/20170727110053/https://www.eia.gov/outlooks/ieo/pdf/0484(2016).pdf. (Accessed: 8th March 2019)
• Liu, J. & Liu Pacifi, J. Addressing the Grand Challenges in Energy Storage. Funct. Mater 23, 924–928 (2013).
• MRS Meeting Scene: TC02: In Situ Studies of Materials Transformations. Available at: https://materials.typepad.com/mrs_meeting_scene/2017/11/tc02-in-situ-studies-of-materials-transformations-1.html. (Accessed: 8th March 2019)
• D8 DISCOVER Family – X-ray Powder Diffractometer, DAVINCI.DESIGN – X-ray Diffraction and Scattering, XRD, Powder | AXS Bruker | Bruker. Available at: https://www.bruker.com/products/x-ray-diffraction-and-elemental-analysis/x-ray-diffraction/d8-discover-family.html. (Accessed: 8th March 2019)
• Electrochemical Atomic Force Microscopy (EC-AFM) – Specialized Atomic Force Microscope Modes | Bruker. Available at: https://www.bruker.com/products/surface-and-dimensional-analysis/atomic-force-microscopes/modes/modes/specialized-modes/ec-afm.html. (Accessed: 8th March 2019)
• Dubal, D. P., Ayyad, O., Ruiz, V. & Gómez-Romero, P. Hybrid Energy Storage: The merging of battery and supercapacitor chemistries.
• Augustyn, V. et al. High-rate electrochemical energy storage through Li+ intercalation pseudocapacitance. Mater. 12, (2013).

Conclusion

Chemical fuel is a uniquely easy-to-utilize and energy dense energy storage medium, which has resulted in its widespread adoption throughout modern transport and industry infrastructure. Despite the impending exhaustion of natural deposits of these fuels and growing environmental problems associated with their use, our dependence on these fuels is greater than ever. As a result, research into new ways of converting, storing and utilizing energy is crucial; both to meet the planet’s energy demands and to mitigate climate change resulting from overuse of fossil fuels.

Biodiesel has gained popularity as a potential replacement for petroleum-derived diesel. As well as being renewable, biodiesel is comparatively low-carbon, and can be used by existing diesel equipment with little to no modification. Since diesel accounts for roughly one third of all energy consumed by the transport sector, biodiesel has the potential to drastically change the use of fuel in the transport sector. The ready availability of biodiesel for these uses is an attractive prospect.

The analysis and characterization of biofuels is crucial to their widespread adoption. This presents a challenge for analytical chemistry technology. Techniques developed in metabolomics have made it possible to glean new insights into synthesis of biofuels. The analysis of local metabolic activity within cells via LC-MS have successfully revealed bottlenecks in biosynthetic pathways by monitoring intermediates and cofactors. This has the potential to assess the impact of engineering new biosynthetic pathways for biofuel, speeding up and improving the development of biofuel synthesis methods. Investigations into other microbial processes such as extracellular electron transfer (EET) also have implications for the development of microbial fuel sources and waste-to-energy applications.

Waste-to-energy technologies offer the dual advantage of providing an efficient storage medium for renewable energy sources and drastically reducing the lifecycle greenhouse gas emissions of hydrocarbon fuels. The principles of waste-to-energy conversion are already being utilized by water utility services for both onsite and offsite power generated from anaerobic digestion of organic material in wastewater. Solar fuels, which use solar energy to synthesize hydrocarbon fuel from atmospheric carbon oxides and other waste carbon sources, are a particularly promising field of research. Recent breakthroughs in the detailed characterization of catalyst activity using IRSEC and FTIR could lead to the creation of commercially viable artificial photosynthesis. Such a technology has the potential to yield hydrocarbon fuels compatible with present-day fossil fuel infrastructure with virtually zero lifetime carbon emissions.

Energy storage technology must be developed in tandem with new renewable energy capacity in order to bridge gaps or valleys in supply. This has spurred research into electrochemical means of storing energy, with the goal of creating a device with the energy density of a conventional battery but the rapid charging and cycle life of a double-layer capacitor. Insights into the behavior of experimental electrochemical systems have been facilitated by the use of coupled operando electrochemical measurements such as STXM, XRD and EC-AFM. The availability of spatially resolved information about the phase, electronic, oxidation and other physical states of electrochemical is key to the development of the next generation of energy storage and conversion materials. Subsequently, an experimental energy storage system Li+ insertion in Nb₂O₅ has been shown to exhibit electron transport properties that facilitate the combination of high energy density and energy transfer rates.

Research into fuel and energy technology is more important than ever before. Advanced analytical technologies play a fundamental role in the understanding and development of these technologies.

Pittcon 2019 will be hosting a number of the world’s leading providers of analytical systems and services for the assessment of fuels, energy efficiency, renewable systems and hybrid materials for energy storage.

Exhibited technology includes new gas-phase UV analytical tools from VUV analytics; chromatography solutions and other oil analysis systems from the likes of Teledyne ISCO, LECO corporation and Petrolab; and FTIR systems from Shimadzu and Thermo Fisher.

Materials analysis Rigaku will be displaying their new ultra-affordable benchtop wavelength-dispersive X-ray fluorescence (WDXRF) spectrometer; and Astoria-Pacific will be exhibiting a wastewater analysis lab. A range of other cutting-edge analytical tools including XRD and EC-AFM will be exhibited by Bruker.

Pittcon 2019 will be taking place at the Pennsylvania Convention Centre in Philadelphia from the 17^th to the 21^st of March.