Nano Energy Research Articles

Tetraglyme Based Electrolytes Enabled Excellent Cycling of Sodium Metal

Sodium metal is a promising anode for batteries because of its high theoretical specific capacity (1165 mAh g-1) and great abundance and low cost. However, fundamental issues such as dendrite formation, “dead sodium” accumulation during cycling, fast SEI dissolution or continuous SEI growth bring challenges for stabilizing reversibility of sodium metal anode. Recent advances in electrolyte engineering and development of highly stable cathode materials have enables sodium metal batteries reaching high CE (>99 %) at room temperature1-5.Herein, we report a feasible pathway toward further stabilization of sodium metal anode using tetraglyme solvent (TEGDME) based electrolyte with various sodium salts (NaBF4, NaPF6, NaTFSI, NaFSI, NaClO4, NaOTf). It is demonstrated that a Na||Cu cell exhibited an average Coulombic efficiency of 99.9 % over 200, 850, and 1000 plating-stripping cycles when an electrolyte of 1M NaOTf in TEGDME, 1M NaPF6 in TEGDME, and 1M NaBF4 in TEGDME were used, respectively. Furthermore, 1M NaBF4 in TEGDME electrolyte also enabled excellent cycling stability of Na||Na3V2(PO4)2 batteries at high rate (1 C) for 1000 cycles with capacity retention of 90.8 %. References Seh, Z. W.; Sun, J.; Sun, Y.; Cui, Y. A Highly Reversible Room Temperature Sodium Metal Anode. ACS Cent. Sci. 2015, 1, 449−455.Cao, R.; Mishra, K.; Li, X.; Qian, J.; Engelhard, M. H.; Bowden, M. E.; Han, K. S.; Mueller, K. T.; Henderson, W. A.; Zhang, J.-G. Enabling Room Temperature Sodium Metal Batteries. Nano Energy 2016, 30, 825−830.Zheng, J.; Chen, S.; Zhao, W.; Song, J.; Engelhard, M.H.; Zhang, J.G. Extremely Stable Sodium Metal Batteries Enabled By Localized High-Concentration Electrolytes, ACS. Energy. Lett. 2018, 315−321.Goktas, M.; Bolli, C.; Buchkheim, J.; Berg, E. J; Novak, P.; Bonilla, F.; Rojo, T.; Komaba, S.; Kubota, K.; Adelhem, P.; Stable and Unstable Diglyme-Based Electrolytes for Batteries With Sodium or Graphite as Electrode., ACS Appl. Mater. Interfaces 2019, 11, 32844-32855.Le, P.M.L; Vo, D.T; Pan, H., Yan, J.; He, Y.; Cao, X.; Nguyen, H.V; Engelhard, M.H; Wang, C.; Xiao, J.; Zhang, J-G., Excellent Cycling Stability of Sodium Anode Enabled by a Stable Solid Electrolyte Interphase Formed in Ether-Based Electrolytes, Adv. Funct. Mater. 2020, 30, 2001151 Acknowledgement This work is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) program under contract no. DE-AC05-76RLO1830.

(Digital Presentation) Small Angle X-Ray Scattering Studies Investigating the Degradation of Electrocatalysts

In the presentation, the application of small angle X-ray scattering (SAXS) in the investigation of degradation phenomena for electrocatalysts is discussed based on recent examples from my work group. In contrast to local methods such as identical location (IL) microscopy1, SAXS probes a microscopic volume of a catalyst film providing representative data for the catalyst. Furthermore, the method can be coupled to operando measurements or to ex situ measurements in gas diffusion electrode setups2. It is demonstrated that the analysis of SAXS data leads to reliable information of change in mean particle size of the catalysts as function of the applied degradation protocol, however, that a proper measurement and control of a background is essential due to the concomitant degradation of the support material. Keeping this in mind SAXS can play a crucial role for not only elucidating and rationalizing degradation phenomena, but also for the testing of concepts for new electrocatalysts with improved stability. Arenz, M. & Zana, A. Fuel cell catalyst degradation: Identical location electron microscopy and related methods. Nano Energy 29, 299–313 (2016).Schröder, J. et al. A New Approach to Probe the Degradation of Fuel Cell Catalysts under Realistic Conditions: Combining Tests in a Gas Diffusion Electrode Setup with Small Angle X-ray Scattering. J. Electrochem. Soc. 167, 134515 (2020).

Toward a Fundamental Understanding of Strain Generation and Strain Tuning for the Fuel Cell Applications

The development of industrial electrocatalysts with excellent performance in fuel cells strongly relies on the fundamental understanding of governing principles of catalysis from fundamental research on well-defined model systems. One particularly successful strategy has been to tune surface strain and thereby modulate the surface electronic structure and energetics of reaction intermediates, leading to a fundamental understanding and identification of catalysts with improved activity. For the well-known example of the oxygen reduction reaction (ORR) on platinum in fuel cells, previous studies indicated that a 1% compressive strain could improve the activity by more than 300%.While the concept of tailoring the reactivity of metal catalysts through surface strain has been discussed over two decades, fundamental challenges remain regarding both strain generation and strain tuning. In the present contribution, We will share our recent progress on these topics, including [1] tunable intrinsic strain in two-dimensional transition metal electrocatalysts, [2] tunable intrinsic strain in stepped transition metal electrocatalysts, and [3] strain tuning of supported transition metal overlayers. We will demonstrate [1] how these fundamental understanding can be used to understand terrace-width dependent ORR activity of stepped Pt surfaces that have puzzled the community over a decade; and [2] how they pave the way toward developing both model electrocatalysts and industrial electrocatalysts with significantly improved performance toward the oxygen reduction reaction.References Wang, Z. Zeng*†, W. Gao, T. Maxson, D. Raciti, M. Giroux, X. Pan, C. Wang, J. Greeley,. Science 2019, 363, 870-874.Wang, W. Gao, Z. Liu, Z. Zeng, Y. Liu, M. Giroux, M. Chi, G. Wang, J. Greeley, X. Pan, C. Wang, ACS Catal. 2018, 8, 35-42.J. Steinbach, C. Duru, A. T. Haug, A. E. Hester, M. Kuznia, K. A. Lewinski, S. M. Luopa, J. T. Petrin, G. M. Thoma, A. J. Kropf, D. J. Myers, D. Yang, D. A. Cullen, J. Greeley, Z. Zeng, ECS Transactions 2017, 80, 659-676.Zeng, J. Greeley, Nano Energy 2016, 29, 369.

Self-powered sensing technologies for human Metaverse interfacing

Dr. Jun Chen is currently an assistant professor in the Department of Bioengineering at the University of California, Los Angeles. His current research focuses on nanotechnology and bioelectronics for energy, sensing, and therapeutic applications in the form of smart textiles, wearables, and body area networks. With a current h-index of 85, he has published 2 books, 1 book chapter, and 230 journal articles, 130 in which he is a corresponding author, in <i>Chemical Reviews</i>, <i>Chemical Society Reviews</i>, <i>Nature Materials</i>, <i>Nature Electronics</i>, <i>Nature Communications</i>, <i>Science Advances</i>, <i>Joule</i>, <i>Matter</i>, and more. Among his many accolades are the Fellow of International Association of Advanced Materials, ACS PMSE Young Investigator Award, UCLA Society of Hellman Fellows Award, Okawa Foundation Research Award, Advanced Materials Rising Star, Materials Today Rising Star Award, ACS Nano Rising Stars Lectureship Award, Chem. Soc. Rev. Emerging Investigator Award, and many others. Beyond research, he is an associate editor of <i>Biosensors and Bioelectronics</i>. Yihao Zhou is currently a postdoc research scholar in the Department of Bioengineering at the University of California, Los Angeles under the supervision of Professor Jun Chen. He holds a BS in materials science from Nanjing University (2013) and a PhD in materials science from Duke University (2019). He has published more than 30 papers, and he appears as first/co-first author for articles in <i>Nature Materials</i>, <i>Nature Communications</i>, and <i>Matter</i>. His research interest includes wearable bioelectronics and electrochemistry. Xiao Xiao is a PhD student in the Department of Bioengineering at the University of California, Los Angeles under the supervision of Professor Jun Chen. Xiao obtained his BS in materials science and engineering from Beihang University in 2020. His research focuses on wearable electronics and smart textiles for energy, sensing, and therapeutic applications. Xiao has already published 47 journal articles, 25 in which he appears as first author, in <i>Science Advances</i>, <i>Chemical Reviews</i>, <i>Advanced Materials</i>, <i>Matter</i>, <i>Trends in Chemistry</i>, <i>Nano Letter</i>, <i>ACS Nano</i>, <i>Nano Energy</i>, and many others. Guorui Chen is currently a PhD candidate in the Department of Bioengineering at the University of California, Los Angeles under the supervision of Professor Jun Chen. He obtained his BS in materials science and engineering from Zhejiang University, China. His research thrust includes bioelectronics, smart textiles, and personalized healthcare. Guorui has already published 34 journal articles, 12 of them in which he appears as first author in <i>Nature Electronics</i>, <i>Chemical Reviews</i>, <i>Matter</i>, <i>ACS Nano</i>, <i>Trends in Biotechnology</i>, and many others. Xun Zhao is a PhD student in the Department of Bioengineering at the University of California, Los Angeles under the supervision of Professor Jun Chen. His current research focuses on wearable and implanted bioelectronics for healthcare applications. He is interested in studying and developing soft materials and systems. Xun has already published 30 journal articles, 10 in which he appears as first author, in <i>Chemical Reviews</i>, <i>Nature Materials</i>, <i>Nature Communications</i>, <i>Joule</i>, <i>Matter</i>, <i>Nano Energy</i>, <i>Advanced Energy Materials</i>, and many others.

Patient‐Specific Self‐Powered Metamaterial Implants for Detecting Bone Healing Progress

AbstractThere is an unmet need for developing a new class of smart medical implants with novel properties and advanced functionalities. Here, the concept of “self‐aware implants” is proposed to enable the creation of a new generation of multifunctional metamaterial implantable devices capable of responding to their environment, empowering themselves, and self‐monitoring their condition. These functionalities are achieved via integrating nano energy harvesting and mechanical metamaterial design paradigms. Various aspects of the proposed concept are highlighted by developing proof‐of‐concept interbody spinal fusion cage implants with self‐sensing, self‐powering, and mechanical tunability features. Bench‐top testing is performed using synthetic biomimetic and human cadaver spine models to evaluate the electrical and mechanical performance of the developed patient‐specific metamaterial implants. The results show that the self‐aware cage implants can diagnose bone healing process using the voltage signals generated internally through their built‐in contact‐electrification mechanisms. The voltage and current generated by the implants under the axial compression forces of the spine models reach 9.2 V and 4.9 nA, respectively. The metamaterial implants can serve as triboelectric nanogenerators to empower low‐power electronics. The capacity of the proposed technology to revolutionize the landscape of implantable devices and to achieve better surgical outcomes is further discussed.

Effect of Doping in Aluminium Nitride (AlN) Nanomaterials: A Review

Piezoelectric materials can generate electrical charges when subjected to mechanical pressure through the piezoelectric effect. In addition to generating electricity from environmental vibrations, they are also used as nano energy generators for micro electro mechanical systems (MEMS). Aluminum Nitride (AlN) with a doping element exhibits unique physical and chemical properties. It is used to manufacture many electromechanical devices. They are ideal candidates for many applications, including MEMS resonators and microwave filters, due to their large piezoelectric coefficient and low resistance. A number of material properties led to its selection, including high thermal conductivity, good mechanical strength, high resistance, corrosion resistance, and the largest piezoelectric coefficient. A piezoelectric coefficient d33 characterizes the piezoelectric response of AlN thin films. By doping this material, a wide range of applications have been explored.

First-principles investigation of the significant anisotropy and ultrahigh thermoelectric efficiency of a novel two-dimensional Ga2I2S2 at room temperature

Two-dimensional (2D) thermoelectric (TE) materials have been widely developed; however, some 2D materials exhibit isotropic phonon, electron transport properties, and poor TE performance, which limit their application scope. Thus, exploring excellent anisotropic and ultrahigh-performance TE materials are very warranted. Herein, we first investigate the phonon thermal and TE properties of a novel 2D-connectivity ternary compound named Ga2I2S2. This paper comprehensively studies the phonon dispersion, phonon anharmonicity, lattice thermal conductivity, electronic structure, carrier mobility, Seebeck coefficient, electrical conductivity, and the dimensionless figure of merit (ZT) versus carrier concentration for 2D Ga2I2S2. We conclude that the in-plane lattice thermal conductivities of Ga2I2S2 at room temperature (300 K) are found to be 1.55 W mK−1 in the X-axis direction (xx-direction) and 3.82 W mK−1 in the Y-axis direction (yy-direction), which means its anisotropy ratio reaches 1.46. Simultaneously, the TE performance of p-type and n-type doping 2D Ga2I2S2 also shows significant anisotropy, giving rise to the ZT peak values of p-type doping in xx- and yy-directions being 0.81 and 1.99, respectively, and those of n-type doping reach ultrahigh values of 7.12 and 2.89 at 300 K, which are obviously higher than the reported values for p-type and n-type doping ternary compound Sn2BiX (ZT∼ 1.70 and ∼2.45 at 300 K) (2020 Nano Energy 67 104283). This work demonstrates that 2D Ga2I2S2 has high anisotropic TE conversion efficiency and can also be used as a new potential room-temperature TE material.

Advanced Technology Evolution Pathways of Nanogenerators: A Novel Framework Based on Multi-Source Data and Knowledge Graph

As an emerging nano energy technology, nanogenerators have been developed rapidly, which makes it crucial to analyze the evolutionary pathways of advanced technology in this field to help estimate the development trend and direction. However, some limitations existed in previous studies. On the one hand, previous studies generally made use of the explicit correlation of data such as citation and cooperation between patents and papers, which ignored the rich semantic information contained in them. On the other hand, the progressive evolutionary process from scientific grants to academic papers and then to patents was not considered. Therefore, this paper proposes a novel framework based on a separated three-layer knowledge graph with several time slices using grant data, paper data, and patent data. Firstly, by the representation learning method and clustering algorithm, several clusters representing specific technologies in different layers and different time slices can be obtained. Then, by calculating the similarity between clusters of different layers, the evolutionary pathways of advanced technology from grants to papers and then to patents is drawn. Finally, this paper monitors the pathways of some developed technologies, which evolve from grants to papers and then to patents, and finds some emerging technologies under research.

Introducing our 2022 Early Career Advisory Board Members

Introducing our 2022 Early Career Advisory Board Members

Blockchain Technology and the Contemporary Business Models; Connecting Nano Energy Storage Devices with Trade for Investors

The rapid rate of growth in nanotechnologies and their application in almost every field of life is not only set to improve the living standards of the general public around the globe but also serves as a great opportunity for business as well. In this regard, a sound business model is required, as the product and services based upon this technology may not conform to traditional business models. In this research, we have reviewed the general business models for Nanotechnology-based products and services. In this respect one of the potential opportunities in the field of Nano energy storage devices and their practical application. We have conceptualized the potential use of “Blockchain” technology in the trading aspect of energy storage contracts and the potential opportunities this presents to the investors as well as the general public who form the wider sphere of stakeholders.

Effect of Reservoir Structural Rhythm on Carbon Capture and Sequestration (CCS) Performance

In addition to the evolution of green and nano energy, sequestration of CO2 is also an evolving method to control the global CO2 footprint and greenhouse effect. Carbon Capture and Sequestration (CCS) is an established technique to capture carbon from anthropogenic sources, such as power and chemical plants, and then inject the same in subsurface rock micropores, to permanently store the CO2. Besides its environmental credentials, CCS also offers economic opportunities in Gas Enhanced Oil Recovery and Methane displacement in coalbed reservoirs. CCS process incorporates various geological, geometrical and engineering understandings of porous media and fluid dynamics. Previous investigators have identified low permeability rock as a better site for CCS. However, little is known of the propagation and effectiveness of CCS in reservoirs that have multiple layers of sedimentation, vis-à-vis well topology and density, flow direction, storage site, and power optimisation. In reality, these layers altogether form a structural rhythm and gradient. In this study, we investigated the structural rhythms and gradients that optimise CCS by using two objective functions (Darcy and interstitial flowrates) and 15 structural criteria (such as pore size, porosity, tortuosity, and aspect ratio). An experimental method has been applied. Five analogous reservoir porous core samples with varying structural parameters have been tested. The results indicate that CCS optimisation is responsive to structural parameters. The rhythm analysis from this study suggests that the CCS gas flow requires a compound rhythm that has a positive porosity and negative pore gradients. That is, the CCS injection wells should be placed in the reservoir area with relatively low porosity (3%) and large pore size (6000nm), while the storage site should be at a relatively high porosity (20%) and smaller pore size (200nm). This study can be directly applied to CCS practice, such that, given a layered reservoir, engineers can predict the well placement or topology that would optimize some of the essential performance objectives of CCS.

An Environmental Sustainability Analysis Tool for Next Generation Lithium Ion Batteries of Electric Vehicles

Lithium-ion batteries (LIBs) are widely used in portable electronics and electric vehicles, but are limited in capacity and energy density. Tremendous efforts have been devoted to the research and development of next-generation LIBs with a high capacity and energy density, particularly through adoption of novel nano-structured materials in the LIB electrodes. The synthesis of nanomaterials, however, involves heavy use of toxic chemicals and nanoparticle emissions, which induce grave concerns on the environmental sustainability of next-generation LIBs. Silicon, with a high theoretical specific capacity, has been recognized as one of the most promising anode materials for next-generation LIBs. In this study, a comprehensive analysis tool is developed to evaluate the environmental sustainability of silicon-based LIBs for EVs by incorporating previously published data, and two nanostructured silicon materials, i.e., silicon nanowires (SiNWs) and silicon nanotubes (SiNTs) are chosen as examples. The purpose is to provide decision support for sustainable design of next-generation LIB technologies by providing overall environmental impact results and feedback to next-generation LIB designers to identify the tradeoffs between technical specifications and sustainability performance. Specifically, this tool based on an Excel spreadsheet comprises six modules, i.e., Dashboard, Material Consumptions, Gas and Aqueous Emissions, Nano Particle Emissions, Energy Consumption, and Life Cycle Impacts. The specifications of the battery packs are inputted in the Dashboard and the environmental impact assessment is conducted through the rest modules utilizing the inputted data to compute each modular results using the embedded formula from our previously published work. The conventional emissions and energy consumption data are characterized with the life cycle impact assessment method for design feedback, while the nanoparticle emission data are experimentally measured and directly used. This analysis tool provides insights into material consumptions and environmental impacts of SiNW-and SiNT-based LIBs and can be expanded for future analyses of other nanostructured next-generation LIB technologies for electric vehicles.

Dual Solutions of EMHD Nanofluid at Stretching Sheet with Mixed Convection Slip Boundary Condition

In this paper stagnation boundary layer flow of nanofluid with mixed convection heat and mass transfer with Electrical Magneto Hydrodynamic (EMHD) effects over a second-order momentum slip boundary condition have been mathematically analysed. The governing equations are transformed by similarity variable and the problem becomes coupled third-order nonlinear coupled differential equations. We use fourth-order Runge Kuta method and shooting technique to find the solution. The effect of second-order momentum slip condition with linear thermal slip condition has determined. Variation of all nano energy conversion parameters depends on different factors has shown graphically. Some of the parameters possesses dual solution at different values of second-order velocity slip parameter (β1&amp;β2).

The influence of organic montmorillonite on the breakdown strength and energy density of poly(vinylidene fluoride)‐based nanocomposites

AbstractCapacitor films with superior transmittance, flexibility, and high performance have attracted considerable attentions in the field of advanced energy storage devices. Nevertheless, the energy density is always increased at the expense of the dielectric constant or breakdown strength on one side. Therefore, based on the above stated issues, energy storage films with good optical transmission and breakdown resistance were prepared by combining a small amount of lamellar organic montmorillonite (OMMT) with poly(vinylidene fluoride) (PVDF) substrates by a simple but effective solution blending method. The addition of OMMT effectively converts the crystalline structure of the PVDF matrix, making it more favorable for dielectric energy storage films, and the polymer‐based nano energy storage films exhibit an optical transmission of approximately 90% at 800 nm. More importantly, the presence of OMMT, a unique lamellar structure, effectively hinders the growth of electrical trees within the polymer composite, thereby improving the overall breakdown strength of the composite. Ultimately, at 0.6 wt% filler content, the PVDF/OMMT nanocomposite exhibited a breakdown strength of 460 MV/m and a discharge energy density of 7.26 J/cm3 as well as an energy efficiency of 69%.

Regulation of nanocrystals structure for high-performance magnetic triboelectric nanogenerator

Triboelectric nanogenerator (TENG) is a kind of capacitive conduction to convert mechanical triggering into electricity, which is the realized applications of Maxwell's equations in the field of nano energy and self-powered systems. As a conductor to participate electrostatic induction, the induction electrode has received little cognition. According to the unified theory of electromagnetics, the investigation of magnetic medium in TENG should not be ignored. Here we fabricate flexible single-electrode triboelectric nanogenerator (S-TENG) by the Micro Electromechanical System (MEMS) compatible technology, including non-destructive peeling technology and in-situ electrodeposition. Specifically, the S-TENG is composed of polydimethylsiloxane (PDMS) as the negative triboelectric layer and electrodeposited nickel as the induction electrode. Theoretically and experimentally, we demonstrate that ferromagnetic Ni electrode could substantially enhance the electrical output of TENG, which is attributed to the generated magnetizing current. The enhancement mechanism proposed in this work follows the law of energy conservation, which utilizes the natural magnetostatic energy inside the ferromagnetic medium and couples the working principle of TENG, thus making great contributions to the output of TENG. Furthermore, the relationship between the magnetic structure and performance is surveyed, and the stability of Ni and Ni-based S-TENG is also investigated. Finally, the proposed strategy for fabricating enhanced and stable Ni electrode is utilized in flexible energy harvester, and shows great prospects in flexible electronics. • The correlation between the micro magnetic structures and performance is investigated. • The magnetization effect in magnetic TENG is demonstrated. • MEMS technology is utilized to fabricate flexible and stable TENG.

All-Solid-state Lithium Battery with Sulfide Electrolyte: From Interface Design to Full Cell

All-solid-state lithium batteries (ASSLBs) have gained intensive attention because of their intrinsic safety and high energy density.1 However, significant interfacial challenges such as detrimental interfacial reactions, poor solid-solid ionic contact, and lithium dendrite growth have stymied the development of ASSLBs. Besides that, the large gap between fundamental research and practical engineering design has slowed down ASSLBs commercialization. Over the past five years, our group has been dedicated to the research and development of ASSLBs, with the aims of overcoming the interfacial challenges and pushing ASSLBs closer to commercialization. First, we have regulated the interfacial ion and electron transport via increasing the ionic conductivity of interfacial buffer layers,2 manipulating interfacial nanostructures,3, 4 using single-crystal cathodes,5 deciphering interfacial reaction mechanisms,6 and constructing artificial solid electrolyte interphases (SEI).7 Based on these advanced and innovative strategies, the large interfacial resistance was successfully eliminated. As a result, ASSLBs with sulfide electrolytes demonstrated both ultra-long cycling stability and high-rate performance. To transfer these viable technologies into practical application and bridging the large gap between laboratory research and practical full cells, we are committed to engineering solid-state pouch cells with competitive energy density and low cost. Recently, a solvent-free and cost-effective process was developed for fabricating ultra-thin inorganic solid electrolyte membranes as well as solid-state thick electrodes. Furthermore, a solid-liquid interface and a plastic crystal electrolyte were engineered to enable practical solid-state pouch cells with high energy density and excellent safety.8, 9 These works not only provide an in-depth understanding of interfacial mass and charge transport but also offer feasible strategies to commercialize practical solid-state pouch cells. References C. Wang, J. Liang, Y. Zhao, M. Zheng, X. Li, X. Sun*, Energy Environ. Sci. , 2021, doi:10.1039/d1ee00551k.C. Wang, J. Liang, S. Hwang, X. Li, Y. Zhao, K. Adair, C. Zhao, X. Li, S. Deng, X. Lin, X. Yang, R. Li, H. Huang, L. Zhang, S. Lu, D. Su and X. Sun*, Nano Energy , 2020, 72, 104686.C. Wang, X. Li, Y. Zhao, M. N. Banis, J. Liang, X. Li, Y. Sun, K. R. Adair, Q. Sun, Y. Liu, F. Zhao, S. Deng, X. Lin, R. Li, Y. Hu, T.-K. Sham, H. Huang, L. Zhang, R. Yang, S. Lu and X. Sun*, Small Methods , 2019, 3, 1900261.C. Wang, J. Liang, M. Jiang, X. Li, S. Mukherjee, K. Adair, M. Zheng, Y. Zhao, F. Zhao, S. Zhang, R. Li, H. Huang, S. Zhao, L. Zhang, S. Lu, C. V. Singh and X. Sun*, Nano Energy, 2020, 76, 105015.C. Wang, R. Yu, S. Hwang, J. Liang, X. Li, C. Zhao, Y. Sun, J. Wang, N. Holmes, R. Li, H. Huang, S. Zhao, L. Zhang, S. Lu, D. Su and X. Sun*, Energy Storage Mater ., 2020, 30, 98-103.C. Wang, S. Hwang, M. Jiang, J. Liang, Y. Sun, K. Adair, M. Zheng, S. Mukherjee, X. Li, R. Li, H. Huang, S. Zhao, L. Zhang, S. Lu, J. Wang, C. V. Singh, D. Su, X. Sun*. Adv. Energy Mater., 2021, 2100210. doi:10.1002/aenm.202100210.C. Wang, Y. Zhao, Q. Sun, X. Li, Y. Liu, J. Liang, X. Li, X. Lin, R. Li, K. R. Adair, L. Zhang, R. Yang, S. Lu and X. Sun*, Nano Energy, 2018, 53, 168-174.C. Wang, Q. Sun, Y. Liu, Y. Zhao, X. Li, X. Lin, M. N. Banis, M. Li, W. Li, K. R. Adair, D. Wang, J. Liang, R. Li, L. Zhang, R. Yang, S. Lu and X. Sun*, Nano Energy, 2018, 48, 35-43.C. Wang, K. R. Adair, J. Liang, X. Li, Y. Sun, X. Li, J. Wang, Q. Sun, F. Zhao, X. Lin, R. Li, H. Huang, L. Zhang, R. Yang, S. Lu and X. Sun*, Adv. Funct. Mater. , 2019, 29, 1900392.

Halide Solid-State Electrolytes: Synthesize and the Atmospheric Stability Study

Rechargeable all-solid-state Li batteries (ASSLBs) are considered as the next generation of electrochemical energy storage systems. Development of solid-state electrolytes (SSEs), which are key materials for ASSLBs, is therefore one of the most important subjects in modern energy storage chemistry. Thus, various types of electrolytes such as polymer-, oxide-, and sulfide-based SSEs have been developed to date and the development of new superionic conductors is still ongoing. Halide SSEs (Li-M-X, M is a metal element, and X is a halogen) are emerging as promising candidates with a number of attractive properties (oxidative stability and interfacial compatibility, etc.). [1] For example, halide SSEs show advantages including high ionic conductivity, wide electrochemical stability windows (0.36-6.71 V vs. Li/Li+), and improved chemical stability toward cathode materials compared to other SSEs. [2-4] Moreover, some of the halide SSEs (such as Li3InCl6 developed by our group) can be directly synthesized in a water solvent with the capability of large-scale production, thus removing the need for special apparatus or handling in an inert atmosphere.In this talk, (i) I will demonstrate the new and salable water-mediated synthesis method of the highly conductive Li3InCl6 halide SSE [5]. (ii) I will report the anion sublattice evolution effect on Li+ conductivity for halide SSEs [6]. I will also show the humidity stability and degradation chemistry of metal halide SSEs investigated by advanced in-situ and operando synchrotron techniques [6-7]. In the end, direct synthesis of halide SSEs on cathode materials by the water-mediated route that has been used to eliminate the interfacial challenges of ASSLBs or act as an interfacial modifier for high-performance all-solid-state Li-O2 batteries will be discussed [8-9].References X. Li, J. Liang, X. Yang, K. R. Adair, C. Wang, F. Zhao, X. Sun, Progress and Perspectives of Halide-based Lithium Conductors for All-Solid-State Lithium Batteries. Energy Environ. Sci., 2020, 13, 1429-1461. J. Liang, X. Li, S. Wang, K. R. Adair, W. Li, Y. Zhao, C. Wang, Y. Hu, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, Y. Mo, X. Sun. Site-Occupation-Tuned Superionic LixScCl3+x Halide Solid Electrolytes for All-Solid-State Batteries. J. Am. Chem. Soc., 2020, 142, 7012-7022. X. Li, J. Liang, J. Luo, M. Banis, C. Wang, W. Li, S. Deng, C. Yu, F. Zhao, Y. Hu, T. Sham, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, K. R. Adair, X. Sun, Air-stable Li3InCl6 electrolyte with high voltage compatibility for all-solid-state batteries, Energy Environ. Sci., 2019, 12, 2665-2671. C. Yu, Y. Li, K. R. Adair, W. Li, K. Goubitz, Y. Zhao, M. J. Willans, M. A. Thijs, C. Wang, F. Zhao, Q. Sun, S. Deng, J. Liang, X. Li, R. Li, T. Sham, H. Huang, S. Lu, S. Zhao, L. Zhang, L. Eijck, Y. Huang, X. Sun, Tuning ionic conductivity and electrode compatibility of Li3YBr6 for high-performance all solid-state Li batteries, Nano Energy, 2020, 77, 105097. X. Li, J. Liang, N. Chen, J. Luo, K. R. Adair, C. Wang, M. Banis, T. Sham, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, X. Sun, Water-Mediated Synthesis of Superionic Halide Solid Electrolyte, Angew. Chem. Int. Ed., 2019, 58, 16427-16432. X. Li, J. Liang, K. R. Adair, J. Li, W. Li, F. Zhao, Y. Hu, T. Sham, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, N. Chen, X. Sun, “Origin of Superionic Li3Y1-xInxCl6 Halide Solid-Electrolytes with High Humidity Tolerance” Nano Lett., 2020, 20, 4384-4392. W. Li, J. Liang, M. Li, K. Adair, X. Li, Y. Hu, Q. Xiao, R. Feng, R. Li, L. Zhang, S. Lu, H. Huang, S. Zhao, T. Sham, X. Sun, Unraveling the Origin of Air Stability of Halide Solid-State Electrolytes by In situ and Operando Synchrotron X-ray analytical techniques, Chem. Mater., 2020, 32, 7019–7027. C. Wang, J. Liang, M. Jiang, X. Li, S. Mukherjee, K. Adair, M. Zheng, Y. Zhao, F. Zhao, S. Zhang, R. Li, H. Huang, S. Zhao, L. Zhang, S. Lu, C. Singh, X. Sun, Interface-Assisted In-situ Growth of Halide Electrolytes Eliminating Interfacial Challenges of All-Inorganic Solid-State Batteries. Nano Energy, 2020, 76, 105015. C. Zhao, J. Liang, X. Li, N. Holmes, C. Wang, J. Wang, F. Zhao, S. Li, Q. Sun, X. Yang, J. Liang, X. Lin, W. Li, R. Li, S. Zhao, H. Huang, L. Zhang, S. Lu, X. Sun, Halide-based solid-state electrolyte as an interfacial modifier for high performance solid-state Li–O2 batteries. Nano Energy, 2020, 75, 105036.

Predicted Impacts of Catalyst Layer Ionomer Microstructure and Distribution on PEMFC Performance

Electric vehicles powered by proton exchange membrane fuel cells (PEMFCs) are a promising means to reduce environmentally harmful emissions. PEMFCs offer low weight, high range (miles traveled before refueling), and quick refueling times; however, persistent technical challenges limit commercialization of fuel cell electric vehicles (FCEVs). In addition to system-level challenges such as an immature refueling infrastructure and H2 production, it remains challenging to manufacture low-cost PEMFCs that meet durability and performance requirements. Addressing the performance issues of low-cost PEMFCs has proven difficult due to a gap in understanding physiochemical resistances within the heterogeneous catalyst layer (CL).Electrochemical reactions occurring in the CL—and therefore PEMFC performance—depend in complex ways upon the CL microstructure. Reactants and products are transported to and from Pt catalysts through nano-thin films of Nafion ionomer, which coat carbon-dispersed Pt catalysts. Through the use of neutron reflectometry (NR) [1,2] and conductivity measurements [3], previous studies show that the structure and material transport properties of Nafion are linked and depend on multiple factors including film thickness, substrate interactions, temperature, and relative humidity. Previously [4], we developed pseudo-2D Newman-type computational models that incorporate novel structure-property relationships derived from these studies. The results concluded that increasing the ionomer film thickness surrounding Pt-covered carbon particles in the CL may lead to a higher PEMFC performance due to an increased conductivity caused by increased ionomer volume fraction and increased Nafion water absorption.In this presentation, we extend our previous model to further advance understanding of how ionomer structure and distribution influence PEMFC performance. The current modeling efforts include two-phase water transport to understand the role of flooding in performance limits under low-Pt loading. Additionally, structure-property relationships from our previous work are updated to include more relevant structures taken from NR experiments performed with Nafion on technologically relevant substrates (Pt and carbon). Presented results will demonstrate the predicted impacts of non-uniform ionomer distribution within the cathode CL, including novel design concepts such as ionomer-rich regions to enhance ion transport for increased catalyst utilization further from the membrane. These predicted impacts provide insight for future PEMFC design modifications to accelerate FCEV commercialization.[1] J. A. Dura, V. S. Murthi, M. Hartman, S. K. Satija, and C. F. Majkrzak, “Multilamellar Interface Structures in Nafion,” Macromolecules, vol. 42, no. 13, pp. 4769–4774, 2009.[2] S. C. DeCaluwe, A. M. Baker, P. Bhargava, J. E. Fischer, and J. A. Dura, “Structure-property relationships at Nafion thin-film interfaces: Thickness effects on hydration and anisotropic ion transport,” Nano Energy, vol. 46, pp. 91–100, 2018.[3] D. K. Paul, R. McCreery, and K. Karan, “Proton Transport Property in Supported Nafion Nanothin Films by Electrochemical Impedance Spectroscopy,” Journal of The Electrochemical Society, vol. 161, no. 14, 2014.[4] C. R. Randall and S. C. DeCaluwe, “Physically Based Modeling of PEMFC Cathode Catalyst Layers: Effective Microstructure and Ionomer Structure-Property Relationship Impacts,” Journal of Electrochemical Energy Conversion and Storage, vol. 17, no. 4, 2020.

(Invited) High-Throughput Synthesis and Characterization of Fe-Based Oxygen Reduction Reaction Electrocatalysts and Perovskite Oxide Oxygen Evolution Electrocatalysts

The sluggish kinetics of oxygen electrocatalysis and the resulting high overpotentials necessary to achieve useful current densities limit the development of promising technologies, such as fuel cells, water and carbon dioxide electrolyzers, and metal–oxygen batteries.1 The best catalysts for both the oxygen reduction and oxygen evolution reactions (ORR and OER, respectively) are based on precious, platinum group metals, such as platinum and iridium, leading to limitations in the cost effective implementation of these technologies.2,3 The development of alternative catalysts, with comparable or higher activity and durability to the PGM catalysts and derived from earth-abundant materials has thus been an active research area for decades.Incredible progress has been made over the past decade in increasing both the ORR activity and durability of PGM-free polymer electrolyte fuel cell (PEFC) cathode catalysts.4 Likewise, impressive progress has been made in developing PGM-free electrocatalysts for the OER in alkaline environments, with perovskite oxides showing activities comparable to PGM-based catalysts.5,6 The class of catalysts demonstrating the highest ORR activities are those typically denoted as “Fe-N-C” and synthesized by heat treating iron salts and zinc-based zeolitic imidazolate frameworks (ZIFs) and/or phenanthroline, as carbon and nitrogen sources, or by heat treating iron-substituted ZIFs. For this class of PGM-free materials, it has been determined that variables such as the metal and carbon-nitrogen macrocycle content, as well as the temperature and atmosphere in which the composites are heat treated are important in determining the activity and stability of the resulting catalysts.7-10 Changing these variables and testing their effect on the resulting catalyst properties is a time-consuming process and only a limited portion of the composition and temperature space have been explored for this broad class of materials. Perovskite oxides are a very broad class of materials with the general formula of ABO3, where the B site is occupied by smaller transition metal ions and the A site by larger cations which have 12-fold coordination with O.5 Both the A sites and B sites can be occupied by multiple metal ions, leading to an even more expansive design space for this class of materials.This presentation will describe the development and application of high-throughput methodology to accelerate exploration of the effects of composition and synthesis parameters on the activity of iron-carbon-nitrogen acidic electrolyte ORR electrocatalysts and perovskite oxide alkaline electrolyte OER catalysts. A multi-channel flow double electrode (m-CFDE) cell and other cells were designed and constructed for simultaneous screening the ORR and OER activity of multiple materials. The structural characterization of the materials using X-ray absorption spectroscopy (XAS) and correlation of the atomic structure with ORR and OER activity will be described, as will the high-throughput testing and optimization of the electrode composition using a 25-electrode array fuel cell hardware.11 References H. Yang, X. Han, A.I. Douka, L. Huang, L. Gong, C. Xia, H.S. Park, and B.Y. Xia, Adv. Func. Mater., 31 (2021) 2007602.B. Pivovar, Nature Catalysis, 2 (2019) 562.S. Thompson and D. Papageorgopoulos, Nature Catalysis, 2 (2019) 558.L. Osmieri, J. Park, D.A. Cullen, P. Zelenay, D.J. Myers, and K.C. Neyerlin, Curr. Opin. Electrochem., 25 (2021) 100627.J. Hwang, R.R. Rao, L. Giordano, Y. Katayama, Y. Yu, and Y. Shao-Horn, Science 358 (2017) 751.J. Suntivich, K.J. May, H.A. Gasteiger, J.B. Goodenough, Y. Shao-Horn, Science, 334 (2011) 1383.X. Wang, H. Zhang, H. Lin, S. Gupta, C. Wang, Z. Tao, H. Fu, T. Wang, J. Zheng, G. Wu, and X. Li, Nano Energy, 25 (2016) 110.H. Zhang, S. Hwang, M. Wang, Z. Feng, S. Karakalos, L. Luo, Z. Qiao, X. Xie, C. Wang, D. Su, Y. Shao, and G. Wu, J. Am. Chem. Soc., 139 (2017) 14143-14149.E. Proietti, F. Jaouen, M. Lefevre, N. Larouche, J. Tian, J. Herranz, and J.-P. Dodelet, Nature Comm. 2 (2011) 1.A. Zitolo, V. Goellner, V. Armel, M.-T. Sougrati, T. Mineva, L. Stievano, E. Fonda, and F. Jaouen, Nature Materials, 14 (2015) 937.J. Park and D.J. Myers, J. Power Sources, 480 (2020) 228801. AcknowledgementsThis work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat). This work was also supported by DOE, Advanced Research Projects Agency-Energy (ARPA-E) under the DIFFERENTIATE program. This work utilized the resources of the Advanced Photon Source, a DOE Office of Science user facility operated by Argonne National Laboratory for DOE Office and was authored by Argonne, a DOE Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.

Platinum Nanowire Based Electrodes with Boosted Catalyst Utilization for Efficient Hydrogen Production in PEM Electrolyzer Cells

Due to the limited triple phase boundary (TPB) sites caused by the intrinsically low electrochemical active surface area (ECSA) of catalysts and poor interfacial contact between a catalyst layer and a porous transport layer, high noble metal catalyst loadings are generally required to achieve high-efficiency hydrogen production in low-temperature proton exchange membrane electrolyzer cells (PEMECs). Our recent studies have demonstrated that direct deposition of platinum nanoparticles onto 25-µm-thick titanium liquid/gas diffusion layers (LGDLs) can significantly reduce the cathode catalyst waste.1-3 To further lower the cost of both catalysts and electrode fabrication, for the first time, we develop a green chemical synthesis approach at room temperature to fabricate ultrathin electrodes composed of platinum nanowires (PtNW) in-situ grown on thin titanium LGDLs.4 Our developed high-speed micro-scale visualization system reveals that ultrathin Pt nanowires display more uniform reaction sites and favorable bubble detachment compared to conventional Pt nanoparticles. Impressively, when integrated into a PEMEC, the PtNW electrode with a low catalyst loading of 0.2 mg cm−2 can achieve a low cell voltage of 1.643 V and high efficiency of 90.08% at 1000 mA cm−2, which significantly surpasses conventional electrodes with high loadings. Such performance enhancement is mainly attributed to the high ECSA of catalysts, favorable hydrogen bubble detachment, and good conductivity of the whole electrode. References Z.Y. Kang, G.Q. Yang, J.K. Mo, Y.F. Li, S.L.Yu, D.A. Cullen, S.T. Retterer, T.J. Toops, G. Bender, B.S. Pivovar, J.B. Green Jr, and F.Y. Zhang. "Novel thin/tunable gas diffusion electrodes with ultra-low catalyst loading for hydrogen evolution reactions in proton exchange membrane electrolyzer cells." Nano Energy. 47, 434-441 (2018).J.K. Mo, Z.Y. Kang, S.T. Retterer, D.A. Cullen, T.J. Toops, J.B. Green Jr, M.M. Mench, and F.Y. Zhang. “Discovery of true electrochemical reactions for ultrahigh catalyst mass activity in water splitting.” Science Advances, 2, 1600690 (2016).Z.Y. Kang, J.K. Mo, G.Q. Yang, S.T. Retterer, D.A. Cullen, T.J. Toops, J.B. Green Jr, M.M. Mench, and F.Y. Zhang. “Investigation of thin/well-tunable liquid/gas diffusion layers exhibiting superior multifunctional performance in low-temperature electrolytic water splitting.” Energy & Environmental Science, 10, 166-175 (2017).Z.Q. Xie, S.L. Yu, G.Q. Yang, K. Li, L. Ding, W.T. Wang, D.A. Cullen, H.M. Meyer III, S.T. Retterer, Z.L. Wu, P.X. Gao and F.Y. Zhang. "Ultrathin platinum nanowire based electrodes for high-efficiency hydrogen generation in practical electrolyzer cells." Chemical Engineering Journal. 410, 128333 (2021).