Energy Storage and Conversion
August 4-6, 2021
Organized by Applied Physics Reviews
Times listed as EDT
August 4 – Day 1
Introductory Comments: 9:00am – 9:15am
Speaker: Chennupati Jagadish
Session 1: Batteries & Supercapacitors
9:15am – 11:15am
Session Chair: Fengxia Geng
9:15am – 10:15am
Designing Electrode Materials and Electrolyte for Alkali Metal-Ion Batteries
Speaker: Zaiping Guo
The University of Adelaide, Australia
Abstract 2Energy storage is essential to realize low carbon society and there have been many challenges. Lithium ion batteries and sodium ion batteries are particularly attracted attention of scientists and engineers as promising devices. Materials engineering plays a key role in the field of battery research. In particular, engineering materials at the nanoscale offers unique properties resulting in high performance electrodes in various energy storage devices. Consequently, considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage devices. Various multi-functional hybrid electrode materials and electrolytes are currently being studied to improve energy and power densities of next generation batteries. In this talk, I will present some of our recent progress in the synthesis of different types of hybrid electrode materials and electrolytes to enhance the electrochemical energy storage properties of metal-ion batteries.
10:15am – 11:15am
Electrochemical Energy Storage with 2D Carbides and Nitrides (MXenes)
Speaker: Yury Gogotsi
Drexel University, USA
Abstract 2D carbides and nitrides, known as MXenes, are among the most recent, but quickly expanding material families. The field is experiencing very fast growth with the number of papers on MXenes doubling every year. Synthesis of dozens of predicted MXenes, demonstration of superconductivity in MXenes with specific surface terminations, stronger interactions with electromagnetic waves compared to metals, metallic conductivity combined with hydrophilicity and redox activity, led to numerous applications. MXenes are promising candidates for energy storage and related electrochemical applications because of 2D gallery spaces for intercalation of ions are available between the MXene sheets. They provide good ionic conductivity and access to redox sites at the transition metal oxide-like surface of MXenes. The ability of MXenes to spontaneously intercalate various cations at high rates enables a variety of electrochemical energy storage applications including double-layer and redox energy storage. The electrochemical storage using aqueous and organic electrolytes, as well as the role of solvation effects and surface chemistry will be discussed. Metallic electronic conductivity exceeding 10,000 S/cm and high mechanical strength of Ti3C2 MXene enables its use as current collector and/or conductive binder, enabling fabrication of current-collector-free electrodes.
11:15am – 12:00pm
Networking Session and Poster Session
12:00pm – 1:00pm
Lunch and Poster Session
Session 2: Light emitting materials and devices
1:00pm – 3:00pm
Session Chair: Harry Ruda
1:00pm – 2:00pm
The Fascinating Properties of Tin-Alloyed Halide Perovskites
Speaker: Maria Antonietta Loi
University of Groningen, The Netherlands
Abstract Low bandgap lead-tin halide perovskites are predicted to be candidates to maximize the performance of single junction and tandem solar cells based on metal halide perovskites. In this presentation I will discuss about the fabrication of highly efficient devices by the addition of long organic cations to the precursors solution, then I will propose a method which involves a template of a two-dimensional (2D) perovskite deposited with a scalable technique (blade coating), which is then converted in-situ to form a highly crystalline three-dimensional (3D) lead-tin perovskite. These templated grown films show an alloy feature with stoichiometric ratio and are highly oriented with the (l00) planes aligning parallel to the substrate. The low surface/volume ratios of the obtained single-crystal-like films contribute to their enhanced stability in different environments.
2:00pm – 3:00pm
Stabilizing Solid-Solution Phases for the Tunable Bandgap in Halide Perovskites
Speaker: Hanwei Gao
Florida State University, USA
Abstract Halide Perovskites have shown potential for high-performance cost-effective optoelectronics. Previous work in this field has been primarily focused on pristine perovskites. We discovered that perovskites in form of composites can sometime outperform the pure perovskites with improved material stability. In this talk, I will focus on the correlation between the crystal phases and microscopic structures and, particularly, how solid-solution phases of the halide perovskites can be stabilized.
3:00pm – 3:45pm
Networking Session
August 5 – Day 2
Introductory Comments: 9:00am – 9:15am
Speaker: Chennupati Jagadish
Session 3: Thermoelectric Materials
9:15am – 11:15pm
Session Chair: Chennupati Jagadish
9:15am – 10:15am
Solution-Processed Thermoelectric Materials: the Case of SnSe
Speaker: Maria Ibáñez
Institute of Science and Technology, Austria
Abstract The conversion of thermal energy to electricity and vice versa through solid-state thermoelectric devices is exceptionally appealing for many applications. Not only because thermal waste energy is generated in many of our most common industrial and domestic processes but also because thermoelectric devices can be used for temperature sensing, refrigeration, etc. However, their extended use has been seriously hampered by the relatively high production cost and low efficiency of thermoelectric materials. The problem is that thermoelectric materials require high electrical conductivity (s), high Seebeck coefficient (S), and low thermal conductivity (k); three strongly interrelated properties.
After decades of research, promising material candidates that are Earth-abundant and low cost have been identified; among them, SnSe. In fact, since the material was “re-discovered” in 2014, SnSe has become the most studied thermoelectric material due to its extraordinary performance in its single crystal form with up to 2.8 values in the figure of merit (ΖΤ=σS2ΤΚ-1). However, the high cost and stagnant production of single crystals and their poor mechanical properties limit the large-scale production of SnSe-based thermoelectric devices. Therefore, a great deal of attention has been placed in replicating the single-crystal charge and thermal transport properties in its polycrystalline counterpart to produce cost-effective materials with enhanced mechanical stability. To date, this has been proven difficult due to the easy oxidation of small crystalline domains, the partial loss of anisotropy, and the difficulty to control the doping level finely. Herein, we present a scalable, low-cost, and environmentally friendly methodology to produce SnSe nanocomposites with outstanding performance. In particular, we synthesize SnSe nanoparticles in water and modify their surface before consolidation to finely tune its electronic structure and its charge and phonon scattering properties to achieve figures of merit up to 2.4. These results are of high promise to introduce waste heat recovery through thermoelectric devices into the market.
10:15am – 11:15am
Circular Thermoelectric Materials
Speaker: Anke Weidenkaff
Technical University Darmstadt, Germany
Abstract Sustainable energy conversion technologies require sustainable substitution materials. The implementation of green chemistry for synthesis and production processes and an efficient circularity of the energy converters with a programmable long lifetime are being introduced as a suitable approach in this talk.
Thermoelectric energy conversion processes to generate electricity from waste heat or to cool in an environmentally friendly way, rely on the long-term reliable heating cooling cyclability of the thermoelectric components and materials including full reversibility of local defect formation, phase segregations, and redox reactions. Therefore, regenerative or self-repairing materials have to be developed to produce long-lasting devices.
Nanostructuration can improve thermoelectric performance via boundary phonon scattering and energy filtering effects. Introducing targeted defects and inclusions leads to dynamic disorder and domain structures, which lower the lattice thermal conductivity, while various nanograin boundaries induce potential barriers which scatter low energy charge carriers to enhance the power factor. The implemented dynamic local inhomogeneities induce metastability and local defects.Nanoinclusions may lead to further phase segregation and decomposition lowering the life time of the device. The formation and regeneration of advantageous local inhomogeneities in long-term heating-cooling cycles of Half-Heusler model systems with improved thermoelectric performance are presented and discussed.
The design of sustainable high performance materials is based on theoretical predictions, life cycle assessment and profound knowledge on composition-structure-property relationships, defect chemistry, ion mobility assessment, and the criticality analysis of applied elements to improve the cycle life of energy converters.
11:15am – 12:00pm
Networking Session and Poster Session
12:00pm – 1:00pm
Lunch and AIP Academy
Chair: Federico Rosei
Session 4: Solar Cells and Photodetectors
1:00pm – 3:00pm
Session Chair: Federico Rosei
1:00pm – 2:00pm
Perovskites for High-Efficiency Solar Cells and Solar Hydrogen
Speaker: Kylie Catchpole
Australian National University, Australia
Abstract Combining perovskites with well-established photovoltaic materials such as silicon is an attractive option for producing cheap, high efficiency and high voltage solar cells. Perovskite/silicon tandems have the potential for further progress in increasing the efficiency to 30% and beyond, and we discuss some of the key ways forward to achieving this goal. We demonstrate a 4-terminal tandem perovskite/silicon configuration in which the efficiency is as high as 27.7% through a passivation approach using 2D perovskites. We also demonstrate efficiency above 21% and fill factor of 83% for a 1cm2 single junction perovskite cell using a nanotextured electrode transport layer. The high efficiency achievable with perovskite/silicon tandems also enable high efficiency for direct solar-to-hydrogen generation, and we demonstrate a system that uses such tandems to achieve a solar-to-hydrogen efficiency of 20%.
2:00pm – 3:00pm
How cheap can solar photovoltaics become?
Speaker: Martin Green
University of New South Wales, Australia
Abstract Over the last decade, the cost of photovoltaic solar energy conversion has dropped very dramatically with solar photovoltaics “now the cheapest source of electricity in most countries” and “now offering some of the lowest cost electricity ever seen”, according to the International Energy Agency. However, improvements are in the pipeline that are leading to an era of “insanely cheap” solar power, within the coming decade.
Several recent studies have detailed how the technology can provide a path to an essentially zero carbon energy future by 2050 without the undesirable cost trade-offs once thought necessary. The developments leading to these cost reductions will be described as well as the pending improvements that will allow solar to continue on its trajectory to even lower future costs.
3:00pm – 3:45pm
Networking Session
August 6 – Day 3
Introductory Comments: 9:00am – 9:15am
Speaker: Chennupati Jagadish
Session 5: Catalytic Materials and Water Splitting
9:15am – 11:15pm
Session Chair: Chennupati Jagadish
9:15am – 11:15am
Photocatalytic Water Splitting for Large Scale Solar Hydrogen Production
Speaker: Kazunari Domen
Shinshu University, Japan, The University of Tokyo, Japan
Abstract Overall water splitting using particulate photocatalysts has received much attention as a means of large-scale renewable solar hydrogen production. 1
Figure 1. A scanning electron microscope image of an Al-doped SrTiO3 photocatalyst loaded with cocatalysts site-selectively.
The author’s group has studied various semiconducting oxides, (oxy)nitrides, and (oxy)chalcogenides as photocatalysts. The apparent quantum yield of overall water splitting using a SrTiO3 photocatalyst has been improved to 95% in the near UV region via refining the photocatalyst and cocatalyst preparation (Fig. 1). 2 This quantum efficiency is the highest yet reported, and indicates that particulate photocatalysts can drive the uphill overall water splitting reaction as efficiently as the photon-to-chemical conversion process in photosynthesis. Moreover, the author’s group has also been developing panel reactors in view of large-scale applications. 3 A solar hydrogen production system with a light-receiving area of 100 m2 was recently built and its performance and system characteristics are under investigation.
It is essential to develop photocatalysts active under visible light irradiation for practical solar energy harvesting. Ta3N5 and Y2Ti2O5S2 photocatalysts show activity in overall water splitting via one-step excitation under visible light irradiation. 4,5 Particulate photocatalyst sheets split water into hydrogen and oxygen via two-step excitation, referred to as Z-scheme, efficiently regardless of the size. In particular, a photocatalyst sheet consisting of La- and Rh-co-doped SrTiO3 and Mo-doped BiVO4 splits water into hydrogen and oxygen via Z-scheme and exhibits STH exceeding 1.0%.6,7 Some other (oxy)chalcogenides and (oxy)nitrides with longer absorption edge wavelengths are also applicable to Z-schematic photocatalyst sheets.
In my talk, the latest progress in the development of photocatalytic materials and their reaction systems will be presented.
References
- Hisatomi et al., Nat. Catal., 2, 387, (2019);
- Takata et al., Nature, 581, 411, (2020);
- Goto et al., Joule, 2, 509, (2018);
- Wang et al., Nat. Catal., 1, 756, (2018);
- Wang et al., Nat. Mater., 18, 827, (2019); 6) Wang et al., Nat. Mater., 15, 611, (2016); 7) Wang et al., J. Am. Chem. Soc. 139, 1675, (2017).
10:15am – 11:15am
In Situ Electrochemical Microreactors for 2D Materials for Energy Applications
Speaker: Judy J. Cha
Yale University, USA
Abstract Two-dimensional (2D) materials, such as graphene and transition metal dichalcogenides (TMDCs), have been explored as lithium-ion battery electrodes and electrocatalysts for various reactions like hydrogen evolution reaction. At the nanoscale, the electrochemical properties of 2D materials can deviate significantly from those studied using bulk crystals or nanocomposite ensembles owing to the thickness-dependent or strain-induced changes in their materials properties. Thus, systematic investigations of electrochemical processes using isolated 2D flakes as a function of thickness, strain, and heterointerface are critical for energy applications using these materials.
In this talk, I will present several lithium-intercalation studies of 2D TMDCs and heterostructures, using nanodevice as in situ electrochemical microreactors, which allow systematic investigations of electrochemical processes in 2D materials with simultaneous probing of structural, electrochemical, and electrical property changes as a function of intercalation, in situ.
Using the in situ microreactors, I will show the nanoscale effects on the thermodynamics of the following intercalation-induced phase transitions: 1) lithium staging in several-layer thick graphene, 2) 2H – 1T’ phase transition of MoS2, MoS2-hBN, and MoS2-graphene heterostructures, and 3) phase transitions in MoTe2 and WTe2. We show a drastic delay in the well-established lithium ordering in graphite due to thickness-dependent strain; control of the charge transfer and 2H-1T’ phase transition in 2D TMDC heterostructures by the nature of heterointerface during lithium intercalation; first observation of intercalation-induced phase transitions in the 2D TMDC tellurides, and the nanoscale heterogeneity in the nucleation and growth of the intercalation-induced phase transition
11:15am – 12:00pm
Networking Session
12:00pm – 1:00pm
Lunch
Session 6: Sensing and Environmental Monitoring Systems
1:00pm – 3:00pm
Session Chair: Amr Helmy
1:00pm – 2:00pm
Metal Oxides Nanostructures: Achievements and Advances in Chemical Sensing
Speaker: Elisabetta Comini
University of Brescia, Italy
Abstract Day by day, the demand for portable, low cost, and efficient chemical/gas-sensing devices is increasing due to worldwide industrial growth for various purposes such as environmental monitoring and health care. To fulfill this demand, nanostructured metal oxides can be used as active materials for chemical/gas sensors due to their high crystallinity, remarkable physical/chemical properties, ease of synthesis, and low cost. In particular, (1D) one-dimensional metal oxides nanostructures, such as nanowires, exhibit a fast response, selectivity, and stability due to their high surface-to-volume ratio, well-defined crystal orientations, controlled unidirectional electrical properties, and self-heating phenomenon. Furthermore the functionalization of metal oxide nanomaterials and the fabrication of heterojunctions are other effective strategies to enhance their response and tune the selectivity to a specific gas. In this case, the formation of a p-n, p-p, or n-n interfaces is a significant factor to improve the reaction between the sensing structure and gaseous compounds. Herein, we report on the novel preparation and characterization of different nanostructures and heterostructures morphologies such as SnO2, CuO, NiO, WO3, Bi2O3 and ZnO NWs, TiO2 nanotubes and NiO/ZnO, NiO/WO3, branched 1D-1D nano-heterostructures and NiO/SnO2, SiO2/SnO2, CuO/ZnO Core-shell, TiO2/GO and ZnO/GO composites and SAM functionalized ZnO NWs. The prepared materials have been analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), UV-Vis and Raman spectroscopy. Finally, chemical gas sensors have been fabricated based on the prepared materials and tested towards a wide range of reducing and oxidizing gases.
2:00pm – 3:00pm
Superior Gas Sensing Devices made by Flame Spray Pyrolysis
Speaker: Sotiris E. Pratsinis
Particle Technology Laboratory, ETH Zurich, Switzerland
Abstract Advances in flame-made gas sensors enable today mobile health monitoring, on-site food safety assessment and air quality tracking to immediately alert people of potential hazards. All these are traced to combustion aerosol technology’s distinct advantages for the assembly of gas sensors compared to their traditional wet chemistry processing: a) very porous sensing films with metastable phase composition, b) embedded noble metals into chemoresistive metal oxide particles and c) capacity for online monitoring of film deposition and conversion of oxides to bromides for sensing NH3 at room temperature (Adv. Sci. 2020: 7, 1903390).
Gas sensors can be extremely compact, inexpensive and highly sensitive but their success is hindered frequently by limited selectivity (ACS Sens. 2019:4, 268). The latter is enhanced drastically by filtration (Mater. Horizons 2021: 8, 661) and the unique nanostructure of flame-deposited sensing films (Adv. Mater. 2008: 20, 3005). So the concept is exemplified, first, by assembling an adsorbent with a flame-made sensor to detect methanol down to ppb in the presence of high ethanol concentrations in both liquor and breath mixtures for prevention of methanol poisoning (Nature Comm. 2019: 10, 4220), a plague in the developing world. Such filter – sensors have been assembled into hand-held devices to detect quantitatively methanol in the presence of high ethanol concentrations in liquors from six continents (Nature Food 2020: 1, 351). Most notably, these devices detected methanol in antiseptics (iScience 2021: 102050) and breath samples of humans that had consumed beer, wine or liquor (Anal. Chem. 2021: 93, 1170). Also this device sensed carcinogenic formaldehyde in real indoor air down to 3 ppb (J. Hazar. Mater. 2020: 399, 123052).
Second, and if time permits, it will be shown how the selectivity is enhanced by continuous catalytic destruction of interferants (ethanol from sanitizers or breath isoprene) on flame-made catalysts before reaching sensors to detect breath acetone (Adv. Sci. 2020: 7, 2001503). Such devices have high selectivity and fast response – recovery times with stable performance over, at least, 145 days, as validated by mass spectrometry and tested with 146 breath samples during exercise and rest of volunteers for lipolysis monitoring (Small Sci. 2021, 1, 2100004).
3:00pm – 3:30pm
Networking Session
3:30pm – 3:45pm
Closing Remarks