bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Conversion of CO2 with Nanoporous Poly(styrene)-Polyvinylpyridine
Authors: Ghebremichael Habte , Sidorenko Alexander
Published: February 2020

The rise in global carbon dioxide emissions poses a grave danger to our society as a whole. The ability to mitigate these harmful emissions would prove invaluable. Electrocatalytic conversion of CO2 provides us a viable pathway for reducing and mitigating emissions. Pyridine moieties have have been to be highly effective at CO2 conversion. By taking advantage of the microphase separation phenomenon with block copolymers, we synthesize nanoporous polystyrene-polyvinylpyridine thin films. We present preliminary results of CO2 conversion within these nanoscale confined reaction vessels.
Impliciations of Transport and pH Effects on Electrocatalytic CO2 Reduction
Authors: Ringe Stefan , Chan Karen , Nørskov Jens
Published: February 2020

Electrocatalytic CO2 reduction has become a highly promising route to sustainable and economical carbon-neutral fuels. So far, however, a basic understanding of the underlying chemical processes is still lacking, mainly due to the highly complex, large reaction network involving a variety of C1 and C2 products. Experimental investigations are additionally aggravated by apparent transport limitations of CO2 to the surface which are also determined by buffer equilibria in solution. Additionally, pH gradients at the solid-liquid interface can be important to consider, since local pH effects have shown to critically influence product selectivities. Such effects overlay (electro-)chemical kinetics which can be modeled e.g. by Density Functional Theory (DFT) in combination with micro-kinetic modeling approaches. However, in order to utilize these methods for the transport limited regime, these need to be extended by equations governing diffusion and migration effects as well as chemical reactions in the electrolyte. Using a coupled kinetic-transport model based on Poisson-Nernst-Planck theory and ab initio calculations of reaction and activation energies, we show transport limitations to be crucial to determining C2 to C1 product selectivity. We present strategies for catalyst structural design to optimize the selectivity towards higher value C2 products.
(Invited) An Overview of H2@Scale and Water Splitting Protocol Development
Authors: Holladay Jamelyn , Pivovar Bryan S , Ayers Katherine E , Marina Olga A , Stechel Ellen B , Xiang Chengxiang("CX")
Published: February 2020

Supplying all of society’s growing energy demands is hard and has been limited to date to the fossil fuel based energy system in place since the start of the industrial age. Hydrogen, as a flexible, clean energy carrying intermediate, has the potential to be a centerpiece of a future energy system where aggressive market penetration of renewables (wind and solar) are coupled with traditional and renewable hydrogen production to increase the U.S. energy security and energy dominance, improve grid resiliency, and meet society’s demands for low cost energy.

A number of key recent changes are bringing hydrogen back into the spotlight: 1) Hydrogen is available from a wide variety of sources ranging from methane reforming to renewable powered water splitting increasing energy security. 2) Renewable energy is getting cheaper, and penetration levels are increasing at an exponential pace. Hydrogen production from curtailed renewables will be low cost and improve grid resiliency; 3) hydrogen uses in industry is increasing; and 4) commercial viability of fuel cell vehicle and other fuel cell technologies has been demonstrated (commercial vehicles being sold). Hydrogen, as an area of R&D interest (from either the federal or private sectors) has had its ups and downs over the past few decades. Hydrogen has suffered at times from being over-hyped or misunderstood. Claims of fuel cell commercialization, in particular, were in the past (early 2000’s) overly optimistic. The safety concerns of hydrogen have also often been poorly understood or overblown. These situations have arisen, in part, due to a lack of appreciation for the science and data of hydrogen and hydrogen systems. Finally, there is substantial efforts for production of hydrogen via water splitting process including: electrolysis, photoelectrochemical, and thermochemical cycles. To accelerate the development of these technologies there is a need for standardized protocols for material and component testing.

This presentation will focus on the role of hydrogen at (grid-)scale and the efforts of a large team assembled to evaluate the potential of hydrogen to play a critical role in our energy future. Facts about hydrogen will be shared, as will the vision of how it will fit into our future energy system. Finally, the presentation will discuss a newly initiated effort for the development of standard test protocols for water splitting using high and low temperature electrolysis, photoelectrochemical, and thermochemical cycles.
Highly Efficient Vitamin-B12 Pyrolyzed N-Co-C Electrocatalyst for Hydrogen Evolution Reaction
Authors: Sabhapathy Palani , Chen Wei-Fu , Shown Indrajit , Chou Tsu-Chin , Chen Kuei-Hsien , Chen Li-Chyong
Published: February 2020

Water splitting by electrocatalysis into hydrogen via the hydrogen evolution reaction (HER) offers a promising solution for green renewable energy generation1. In past several years, Pt and Pt based nanomaterials are the mostly served as an efficient electrocatalyst for HER; however, due to high-cost and low abundancy of Pt limits its vast utility for the commercial HER application. Therefore, it's highly needed to develop nonprecious metal based electrocatalyst for HER towards cost effective commercial application2. Over the past decades, tremendous efforts have been made for replacing the Pt based electrocatalysts for HER. Recent advances in carbon nanomaterials (RGO, CNT, etc.,) have shown their promising future in energy-related electrocatalytic reactions, such as ORR, OER, and HER. After heteroatom (such as N, B, P, and S) doping, the enhanced catalysis activity of carbon nanomaterials has been widely illustrated for ORR. Among all the reported electrocatalysts, the co-doping of trace transition metals on heteroatoms doped carbon materials leads to form metal complexes (Ex. Co-Nx), showing promising HER activity in the aqueous electrolyte. In addition, the reported density functional theory (DFT) simulation shows that when combining both coordinations into one complex, the optimized charge distribution results in an ideal value of ΔGH in Metal-Carbon-Nitrogen (M-C-N) hybrid system and which is much better than the single or mixture system of M-C and M-N3.

In this presentation, we will demonstrate a new HER electrocatalyst based on N-Co-C system. The N-Co-C catalysts are prepared by a one-step pyrolysis process at the high temperature in which vitamin-B12 used as a metal precursor together with reduced graphene oxide (RGO). We observed that the electrocatalytic activities of N-Co-C catalysts are strongly related with the pyrolysis temperature and metal loading. The N-Co-C catalyst pyrolyzed at 800oC showed the highest HER activity with lowest overpotential of 110 mV at a current density of 10 mA cm-2. It shows the optimum Tafel slope of 65 mV decade-1 and excellent stability over 20 h in acidic condition. The as synthesized catalyst was characterized by XRD, XPS and XAS. The results indicate that Co-corrin complexes (Vitamin B12) together with RGO have been decomposed at the high temperature to form N-Co-C structure. This conjugation induces that, downshift of the d-band center of cobalt, and thereby decreases its hydrogen binding energy. This, in turn, favors the electrochemical desorption of Hads and leads to a relatively moderate Co−H binding strength, resulting in the enhancement of the hydrogen evolution reaction. The comparison of HER activity and stability of N-Co-C electrocatalyst in alkaline electrolytes will be discussed at the meeting.
Highly Active and Durable Ir Catalyst for Oxygen Evolution Reaction for Proton Exchange Membrane Electrolysis
Authors: Xu Hui , Yan Litao , Zhao Shuai , More Karren L. , Stone Robert
Published: February 2020

In the proton exchange membrane (PEM) water electrolysis, iridium (Ir) or iridium oxide (IrOx) black is the primary catalyst for the oxygen reduction reaction (OER) at the anode. Changing Ir black to Ir nanoparticles (3-4 nm) could significantly increase the catalyst activity of the OER and thus lowering the Ir loading. Under harsh PEM water electrolysis operating conditions, it is challenging to find electrically conductive and electrochemically stable supports to deposit Ir or IrOx nanoparticles The high operating potential, oxidation atmosphere and strong acid conditions has limited the application of carbon black, a most common support used in PEM fuel cells. In this work, iridium nanoparticles with a conductive chain was formed and deposited on high surface area tungsten doped TiO2 support (Ti1-xWxO2), named as Ir/Ti1-xWxO2. The continuous conductive chain could be formed by manipulating the catalyst synthesis conditions. To demonstrate the significance of the conductive chain in the electrochemical test, the Ir/Ti1-xWxO2 catalyst modified with an additional layer of IrO2, named as Ir/IrO2/Ti1-xWxO2, was prepared. Partial amount of iridium nanoparticles without conductive chain was oxidized to iridium oxide, and subsequently, another layer of iridium nanoparticles was deposited on the IrO2/Ti1-xWxO2 support to form an iridium/iridium oxide conductive chain. The electrochemical tests demonstrated that these two categories of catalysts with conductive chain exhibited high initial performance and durability for OER in PEM electrolyzers.

The synthesized catalyst Ir/ WxTi1-xO2 demonstrated 5-time higher mass activity than industrial standard Ir black baseline, from rotating-disk electrodes (RDE) studies. While being tested in real water electrolyzers, the synthesized catalyst enabled to lower the Ir loading by an order of magnitude while retaining a similar electrolzyer performance of the baseline Ir black catalyst. The Ir/WxTi1-xO2 catalyst also demonstrated remarkable stability as only small voltage (<20 mV) increase was observed in a 3000-hour durability at a constant current density of 2000 mA/cm2.
(Invited) Experimental and Theoretical Approaches to High Performance, Robust HER and Oxygen Evolution Reaction (OER) Electrocatalysts for Proton Exchange Membrane Based Water Electrolysis
Authors: Kumta Prashant N
Published: February 2020

Water electrolysis is a well-known approach for the generation of clean and sustainable hydrogen via acid, alkaline and neutral mediated systems. Proton exchange membrane (PEM) based acid mediated water electrolysis is considered highly advantageous and one of the most reliable technologies for hydrogen generation and oxygen evolution among all other conventional hydrogen production approaches. However, the systems have yet to reach commercialization levels due to the use of highly expensive precious metal or platinum group metal (PGM) based electro-catalysts such as Pt, RuO2, and IrO2, all well-known for their excellent electrocatalytic activity and stability for both hydrogen and oxygen evolution reactions.

There is a considerable need for the identification of non-noble metal based electrocatalysts for acid mediated water electrolysis. Over the years, we have focused our efforts at generation of novel transition metal based oxide solid solutions containing reduced amounts of noble metal oxide species. First principles density functional theoretical (DFT) based calculations largely aided by the use of the Vienna ab-initio simulation package (VASP) have been utilized to identify these novel solid solutions largely mimicking the electronic structure of the noble metal electrocatalyst systems. These theoretical calculations formed the basis for the identification of various reduced noble metal oxide containing solid solutions. These initial studies and theoretical understanding of the reaction mechanisms formed the basis for eventually identifying completely non-noble metal containing compositions. All of these systems display electrochemical activity comparable or even superior to the noble metal counterparts. Chronoamperometry studies in fact, indicate the systems to show even more robust electrocatalytic performance under primarily acid mediated conditions while being equally effective under basic and neutral pH conditions as well.

This presentation will outline and summarize the collective efforts undertaken by my group over the years to identify low noble metal containing electrocatalysts as well as our recent findings of a completely non-noble metal based ternary transition metal oxide solid solution containing electronegative anion such as fluorine and its promising electrocatalytic response for water electrolysis and oxygen evolution reactions. Results of the studies conducted over the years will be presented while outlining future plans and strategies for the identification of such non-noble metal and non PGM based electrocatalysts for acid mediated water electrolysis.
Tracking Feni Nanoparticle Surface Inclusions after Electrochemical Aging for the Oxygen Evolution Reaction
Authors: Taylor Audrey K. , Louie Mikayla E. , Andreu Irene , Paul Michael T.Y. , Gates Byron D.
Published: February 2020

Improving the efficiency of the oxygen evolution reaction (OER) could be highly beneficial to a variety of clean energy applications. Technologies that include fuel cells, electrolyzers, and metal-air batteries are often limited by the cost and scarcity of precious metal catalysts. There is, therefore, a desire to identify earth-abundant electrocatalysts that exhibit reduced overpotentials and to prepare nanocatalyst structures that both efficiently utilize and increase the active surface area of these materials. Recently, the intentional inclusion of Fe into Ni oxide thin films to prepare electrodes of a homogenous composition have exhibited a reduction in their overpotentials and improved overall catalytic activity. The incorporation of discreet FeNi nanoparticles (NPs) into the surfaces of Ni electrodes has not, as of yet, been fully explored and is of interest to assess how these surface inclusions and morphologies may change with prolonged electrochemical aging.

In this work, dimpled Ni electrodes supporting FeNi NPs were prepared by electroplating around spherical poly(styrene) (PS) templates (500-nm in diameter). The PS spheres were coated with FeNi NPs using solution-phase assembly techniques. The NP coated PS spheres served two functions: (i) creating regular dimpled features for tracking the electrode morphology; and (ii) positioning the FeNi NPs at the electrode surfaces within these dimpled features. Alkaline electrochemical aging by cyclic voltammetry (CV) was conducted to achieve an adequately stable Ni oxy-hydroxide phase prior to the OER measurements. Changes to the composition and morphology of these electrodes, both before and after electrochemical measurements, were monitored by scanning and transmission electron microscopy techniques including correlative energy dispersive X-ray spectroscopy. The FeNi NPs coated on Ni electrodes demonstrated a higher electrochemical activity for the OER than dimpled Ni electrodes without the FeNi NPs.
Nanostructured Nickel Selenides for High Efficiency Water Oxidation Electrocatalysis
Authors: De Silva Umanga , Allada Diya , Masud Jahangir , Nath Manashi
Published: February 2020

While oxygen evolution reaction (OER) taking place at the anode during water splitting reaction, is a very promising route towards clean and renewable energy, synthesis of highly efficient OER catalysts from earth-abundant, precious metal-free resources is the most challenging aspect of the field. We have synthesized a series of nanostructured nickel selenides, NiSe, NiSe2, Ni3Se2 and Ni3Se4 as active catalytic materials for the OER in alkaline medium. While Ni has been proven to show promising catalytic activity, the significant improvement in efficiency observed in this series towards OER can also be partly due to the formed nanostructured interface which increases the exposed surface area of the catalyst. These pure nickel selenides were synthesized by hydrothermal reactions and showed low overpotential at 10 mA cm-2 current density, early onset of catalytic activity, as well as high overall current density during the OER electrocatalytic activity in 1.0 M KOH. The overpotentials at 10 mA cm-2 current density for the above series of nickel selenides are 220, 200, 240 and 250 mV, for NiSe, NiSe2, Ni­3Se2 and Ni3Se4, respectively. Additionally, we have also investigated the stability of this catalyst during long-term OER conditions under 1.0 M KOH, which confirmed that these electrocatalysts maintained their structural and compositional integrity under operational condition for extended period of time. In this presentation we will discuss about the effect of nanostructured morphology on electrocatalytic performance and will offer some insight about designing better electrocatalysts incorporating morphology control. The synthesis of nanostructured electrocatalysts, characterization techniques such as XRD, SEM, TEM and STEM, and detailed electrochemical investigations for catalytic activity will be also discussed.
Exceptional Electrocatalytic Oxygen Evolution Via Tunable Charge Transfer Interactions in Perovskites and Perovskite Derivatives
Authors: Forslund Robin , Hardin William G. , Johnston Keith P. , Stevenson Keith J
Published: February 2020

Efficiency of both water electrolyzers for low cost hydrogen generation as well as rechargeable metal-air batteries needs to be increased to further the pragmatic development of these key technologies. Given that the efficiencies of these technologies are limited primarily by the sluggish kinetics of the oxygen evolution reaction (OER), great efforts have been made to reduce the overpotentials for the OER in alkaline media with advanced catalysts. While precious metals such as Ir and Ru are standard OER catalysts in acidic electrolytes, alkaline electrolytes enable the use of earth-abundant, non-precious metals. Using selective substitution of A and B-sites within perovskite and perovskite derivatives to control the extent of hybridization between transition metal e
g
and p(O) bands, we demonstrate exceptional OER activity. Furthermore, the enhanced covalency achieved through these substitutions leads to a new OER mechanism that utilizes lattice oxygen while the oxygen reduction activity is improved via increased contributions from the catalyst support.
Electrochemical Preparation of Copper-Cobalt Oxide Nanosheets Array on Nickel Foam As the Catalyst for Oxygen Evolution Reaction
Authors: Choi Woo-Sung , Jang Myeong Je , Park Yoo Sei , Lee Kyu Hwan , Choi Sung Mook
Published: February 2020

Development of sustainable energy has recalled highly efficient energy storage technology because it generates the electricity stochastically from the sources such as solar and wind. The water electrolysis has been considered as the one of the promising options to convert and store electrical energy as the form of hydrogen. However, relatively large overpotential from anodic half reaction, that is, oxygen evolution reaction (OER) has hindered commercial use of hydropower.

The recent studies about OER have focused on finding out non-noble metal catalyst because the RuO2 and IrO2, ideal catalysts for OER, are scarce and expensive. Among the non-noble metal oxides, cobalt (III, IV) oxide has been received great attention since it is anticipated to be second best ideal catalyst for OER from theoretical calculations. With this respect, the number of nano-sized cobalt oxide electrodes with different morphologies have been prepared and utilized as the anode of electrolytic water splitting system.

In this work, copper-cobalt oxides nanosheets catalyst layer was electrochemically prepared on the nickel foam substrate. To achieve nano-porous morphology of deposit, cobalt oxide was co-deposited with copper oxide. The structural and spectroscopic analyses revealed that cobalt-copper oxides nanosheet array consists of mixture of Co3O4 and CuxCo3-xO4. As the catalyst for OER, the resulting catalyst showed exceptional catalytic activity thanks to its nano- to micro-porous structure, which allows facile transport of active species. Furthermore, it showed great long-term stability.

In this presentation, the catalytic activity of cobalt-copper oxides will be discussed in terms of electrochemical properties. In particular, several electrochemical parameters such as anodic Tafel slopes and overpotentials at different current densities will be suggested and compared to that of other nanostructured catalysts reported in literature. Furthermore, the effect co-deposition of copper and cobalt oxides on growth habit of overall deposit and its OER performance will be discussed.
Activity and Stability Trend of Transition Metal Hydr(oxy)Oxide for Oxygen Evolution Reaction
Authors: Chung Dong Young , Martins Pedro F. B. D. , Lopes Pietro Papa , Strmcnik Dusan , Stamenkovic Vojislav , Markovic Nenad M
Published: February 2020

Electrocatalyst for water electrolyser is one of the promising research fields for various renewable energy applications due to current energy problem. Although recent advances in developing efficient electrocatalysts have been achieved by various strategies including alloy, doping and shape control, there still remain large gaps to be resolved. To address these issues, fundamental understanding of functional links between activity and durability is timely urgent. In this talk, discussions on the activity and durability trend of transition metal based hydr(oxy)oxide electrocatalyst in alkaline media will be covered. Based on the fundamental understanding of functional relationship, effective material design strategies for durable and active electrocatalyst and discussion the role of each design principles for durability enhancement will be presented.
(Invited) Enhancing HER and OER Electrocatalysis
Authors: Lopes Pietro Papa , Strmcnik Dusan , Li Dongguo , Markovic Nenad M , Stamenkovic Vojislav
Published: February 2020

Fundamental understanding of the processes involved in that are behind the mechanism for electrochemical evolution of hydrogen and oxygen from water is considered critical in for further advancement of materials that could be implemented in electrolyzers,. Atomic scale insight at the electrified solid-liquid interfaces provides invaluable guidance to overcome limitations that cause a lower than desired operating efficiency of the devices. All of that highlights the need for development of more active, durable and cost effective oxygen evolution (OER) and hydrogen evolution (HER) reaction catalysts. While the majority of research is placed on the catalyst design and synthesis aiming to improve their efficiency, not too much less has been done to resolve and understand a the impact of the liquid phase of the interface at which reaction is taking place. In addition to surface structure, surface and subsurface composition and electronic properties, the role of liquid phase which is influencing the overall performance of an electrified interface is being investigated. Molecular species from the electrolyte and the nature of their interaction with the catalyst surface will be discussed. The knowledge acquired from two-dimensional surfaces has been employed to create real-world catalysts with superior properties.
Hydrogen Bubble Templating of Fractal Ni Foams for Water Oxidation in Alkaline Media
Authors: Garbarino Sebastien , Charbonneau Valérie , Nzone Fomena Nadège , Gaudet Julie , Bruce David R , Guay Daniel
Published: February 2020

Dynamic Hydrogen Bubble Templating of Ni electrodes (NiDHBT) is applied to form fractal macroporous structures and their properties towards oxygen evolution reaction (OER) is assessed. Upon varying Ni electrodeposition conditions, morphological features with percolating porosity were finely tuned and electrochemical activity towards O2 evolution reaction (OER) in 1M KOH were enhanced. As demonstrated by cyclic voltammetry, NiDHBT electrochemical features displayed a tremendous increase (x 250) of the electrochemically active Ni surface atoms, with strong mechanical adherence to the underlying substrate.

Under constant electrolysis (0.25 A cm-2), OER potentials remained stable and occurred at lower potentials (shifted by ca. 300 mV) as compared to a bare Ni plate. Contact angle measurements confirm the super-aerophobic nature of the fractal Ni films, which leads to fast and sustainable release of O2 bubbles during potentiostatic measurements. Due to the versatility of the DHBT method, fractal Ni-based, e.g. NixFe1-x, electrodes for use in advanced electrolysis cell configurations can be envisioned, to further examine transport enhancement in relevant industrial systems and its tolerance to commercial alkaline solutions.
Tuning Ni Surfaces for Enhanced Oxygen Evolution Reaction in Alkaline pH
Authors: Kendrick Ian , Bates Michael , Jia Qingying , Doan Huong , Liang Wentao , Mukerjee Sanjeev
Published: February 2020

Mixed-metal oxide (MMO) films consisting of Ni-Fe and Ni-Co-Fe were investigated as electrocatalysts for the oxygen evolution reaction (OER) under alkaline conditions.[1] High surface area Ni-Fe-Co films on a Raney nickel support were produced by using aniline as a capping agent to optimize the catalyst morphology. The Raney nickel support provides excellent catalyst dispersion which results in high-active site utilization. This catalyst shows enhanced mass activity when compared to other Ni-Fe OER electrocatalysts.[2-4] Cyclic voltammetry of binary MMO catalysts shows changes in the Ni2+/3+
transitions in films containing Fe or Co. In-situ X-ray absorption spectroscopy (XAS) analysis verifies the hypothesis that Fe stabilizes Ni in the 2+ oxidation state while Co facilitates oxidation to the 3+ state. The enhancement of the OER from the Ni-Fe-Co catalyst is a result of two effects (1) the presence of Co effectively “shrinks” the Ni and Fe local geometry resulting in an optimized Fe-OH/OOH bond strength and (2) the formation of a conductive NiIIIOOH phase at a lower overpotential as a result of charge transfer effects from Co. This conductive phase activates Fe sites which are inaccessible to electron transfer in the nonconductive NiII(OH)2 lattice. Heat treatment studies of films at 400 oC in the presence of air show an improvement the OER activity of the Ni-Fe-Co catalyst but deactivates the Ni-Fe. This presentation will entail detailed correlation of electrochemical data (RDE and single cell) with in situ spectroscopy obtained using Raman and Synchrotron x-ray absorption.

Acknowledgements:

The authors gratefully acknowledge the financial support of the Department of Energy (DOE) via Energy Efficiency and Renewable Energy (EERE), under the auspices of an incubator effort lead by Proton On-Site and a new grant (DE-EE0006958 ) under the HydroGen initiative. Authors also acknowledge the support from arpa.e under their open initiative via a grant lead by Pajarito Powders, Albuquerque (DE-AR0000688). The support from (DOE) office of science under contract no DE-SC0012704 for building and maintaining the National Synchrotron Light Source-II (NSLS-II) at Brookhaven National Laboratory (BNL), Upton, NY and Thermo Fisher for instrumental support is gratefully acknowledged.

References

Bates, M.K., et al., Charge-Transfer Effects in Ni–Fe and Ni–Fe–Co Mixed-Metal Oxides for the Alkaline Oxygen Evolution Reaction. ACS Catalysis, 2016. 6(1): p. 155-161.

Song, F. and X. Hu, Exfoliation of layered double hydroxides for enhanced oxygen evolution catalysis. Nature communications, 2014. 5.

Gong, M., et al., An Advanced Ni–Fe Layered Double Hydroxide Electrocatalyst for Water Oxidation. Journal of the American Chemical Society, 2013. 135(23): p. 8452-8455.

Tang, D., et al., Carbon Quantum Dot/NiFe Layered Double-Hydroxide Composite as a Highly Efficient Electrocatalyst for Water Oxidation. ACS Applied Materials & Interfaces, 2014. 6(10): p. 7918-7925.
Bioinspired Mo2c-Based Catalyst with the Optimized P and S Heteroatom Incorporation for Efficient Hydrogen Production in Alkaline Media
Authors: Ahn Taeyong , Sim Uk
Published: February 2020

The development of efficient and low-cost catalysts for water splitting is a fundamental challenge for electrochemical hydrogen production. For commercialization of water electrolyzer, highly efficient catalyst for hydrogen evolution reaction (HER) under basic condition is required. Low-cost molybdenum-based catalysts have attracted much attention, but they have not proven to be sufficiently active or stable in alkaline media. Inspired by biomolecular systems, we now present our successful use of polydopamines, a component of adhesive proteins secreted by marine mussels, to synthesize a new, enhanced molybdenum-based catalyst. Moreover, through combinatorial controlling P and S heteroatom elements, further enhanced electrochemical performance was realized.

Firstly, to study the effect of P incorporation, we synthesized Mo2C:P using a hydrothermal process. Dopamine (2 mg) was used as a monomer and mixed in tris-(hydroxy-methyl) aminomethane solution (10 mM, pH 8.5). Mo precursors in ammonium heptamolybate (3 mM) and the P precursors in ammonium phosphate (0 to 100 mM) were introduced into the dopamine solution. In order to carbonize the solution, it was dried and then thermally treated in a nitrogen-rich tube furnace at 800 ℃. The electrocatalytic activity of the catalyst was measured using cyclic voltammetry with a rotating disk electrode system in a three-electrode cell at 1M KOH. The 50mM of P sample showed optimal HER catalytic activity, showing the overpotential of 133 mV to attain a current density of 10 mA/cm2.

Further improvement could be achieved via S incorporation into the optimized Mo2C:P catalyst. To find optimal concentration of S element, S precursors in sodium sulfide (0 to 50 mM) were introduced into the dopamine solution with Mo and P precursors and the solution was dried and carbonized at 800 ℃. From the current-potential plot, the overpotential was further decreased (113 mV). From XRD, TEM and XPS analysis, we also identified that the incorporation of S and P changed the crystallinity and electronic structure on the surface, possibly resulting in the improved electrochemical performance.

In conclusion, we have designed a new bio-mimetic Mo2C:S:P catalyst with enhanced HER properties. The significant catalytic enhancement achieved in this study emphasizes the potential to be explored in strategies applying bioinspired materials as HER catalysts.
The Effect of Different Mixing Processes on the Ionic and Electronic Conductivities of Li-Ion Battery Electrodes
Authors: Pouraghajan Fezzeh , Thompson Andrea I , Vogel John E , Mazzeo Brian A , Wheeler Dean R.
Published: February 2020

In addition to the characteristics of the materials that make up the electrode (such as active material and additives) and the ratios in which the materials are combined, the electrode fabrication process itself plays an important role in the cell performance. This is because the fabrication process is a contributing factor in determining the distribution of particles and the microstructure of the electrode. The first step to making a uniform electrode structure is making a well-mixed slurry. Generally it is believed that too obtain a reliable, high quality electrode, it is essential to avoid agglomeration of the active materials and conductive additives since agglomeration could result in poor transport behavior in the electrode. Highly energetic mixing has been observed to improve cell performance in some cases [1].

In this work, the effect of mixing processes on the microstructure of porous Li-ion battery electrodes is studied through directly measuring electrode tortuosity and local electronic conductivity. Different types of mixing processes were performed by varying, for instance, the speed of mixing. For measuring tortuosity the blocking electrolyte method is used [2]. This method is based on an AC-impedance measurement of the electrode sample using a non-intercalating or blocking electrolyte. For electronic conductivity measurements, a flexible surface conductivity probe was used [3]

This research was funded by the BMR program of the US Department of Energy.

[1] Dreger et al., Abstract 326, PRiME 2016, Honolulu, HI.

[2] Landesfeind et al., J. Electrochem. Soc. 163, A1373, (2016).

[3] Hardy et al., Abstract 113, 231st Meeting of the Electrochemical Society, New Orleans, LA, (2017)
Ultrathin Polyelectrolytes for Solid State 3D Lithium Microbatteries
Authors: Gao Yifan , Tenhaeff Wyatt
Published: February 2020

Lithium ion batteries are widely used for portable electronics, particularly laptops and mobile phones, due to their superior energy and power densities. As modern microelectronic devices and microelectronic mechanical systems (MEMS) advance further, the bottleneck to further miniaturization is often energy storage.1 While solid state thin film batteries offer remarkable electrochemical performance and long term stability, they are limited by areal capacity (mAh/cm2).2 Solid state three dimensional lithium ion micro-batteries (3D micro-batteries, for short) are an attempt to realize the exceptional electrochemical performance of thin film batteries by fabricating solid state lithium ion cells on high specific surface area. The challenge to realizing these battery designs is the preparation of conformal, ultrathin solid-state electrolytes that physically separate the two electrodes while allowing rapid ion transport. Using initiated chemical vapor deposition, 1µm-thick crosslinked polymer thin films composed of poly (methacrylic acid-co-ethylene glycol diacrylate) were synthesized. These films were transformed to lithium-bearing polyelectrolytes through H+/Li+ ion exchange in a 1M LiOCH3 solution in methanol. Fourier transform infrared spectroscopy (FTIR) characterization was used to determine the chemical composition of the copolymer film and confirm successful ion exchange through analysis of the vibrational stretch of the carbonyl (C=O) bonds in the acidic and salt forms of the polymer electrolyte. The effect of crosslinking densities in these films (the mole fraction of ethylene glycol diacrylate) on electrochemical properties was studied. The optimal ionic conductivity of the Li+-exchanged polymer was determined to be 3.75x10-7 S/cm at 60°C with an activation energy of 0.8785eV. The electrochemical stability of this electrolyte is still under investigation through cycling in thin film cells where vapor-deposited lithium metal as the anode and Au as the working electrode. Current efforts to further enhance ionic conductivity and to integrate these materials into full solid state lithium metal batteries will also be presented.

1. Letiche, M.; Eustache, E.; Freixas, J.; Demortiere, A.; De Andrade, V.; Morgenroth, L.; Tilmant, P.; Vaurette, F.; Troadec, D.; Roussel, P.; Brousse, T.; Lethien, C., Atomic Layer Deposition of Functional Layers for on Chip 3D Li-Ion All Solid State Microbattery. Adv. Energy Mater.
2017,
7 (2), 12.

2. Ferrari, S.; Loveridge, M.; Beattie, S. D.; Jahn, M.; Dashwood, R. J.; Bhagat, R., Latest advances in the manufacturing of 3D rechargeable lithium microbatteries. Journal of Power Sources
2015,
286, 25-46.
New Avenues into Fluorinated Organic Electrolytes for Li-S Cells
Authors: Meisner Quinton James , Glossmann Tobias , Hintennach Andreas , Zhu Lei , Zhang Lu , Zhang Zhengcheng
Published: February 2020

Lithium-sulfur batteries are considered as one of the most promising battery chemistries for the next generation electrochemical energy storage. Due to remaining challenges with respect to lithium polysulfide dissolution and subsequent redox shuttling/active material loss, current lithium-sulfur batteries remain unviable for wide applications in both electric vehicle and stationary electrical grid. In the recent years, several electrolytes and electrolyte additives have been reported using a fluorinated ether based compound to address the issues associated with polysulfide dissolution/shuttling and fast capacity fading, however the exact function and the structure-property correlation of these fluorinated ethers remain largely unknown. Current efforts from our group in this area have expanded to new fluorinated ethers with different degrees and patterns of fluorination and various skeletal structures of substitutions. One area is the fluorinated aliphatic ether based solvents with inspiration drawn from previously reported 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE). A quick overview of the research into a newly designed fluorinated benzyl ether based solvents will also be presented which have been investigated by our group to further mitigate the polysulfide dissolution due to the strong interaction between the fluorinated benzyl group and the polysulfide anions.

Figure 1
Fast Formation Cycling for Nickel-Rich NMC/Graphite Lithium Ion Batteries
Authors: Mao Chengyu , Ruther Rose E. , Wood David L
Published: February 2020

The development of nickel-rich NMC cathodes (LiNixMnyCo1-x-yO2 with x > 0.5) is among the most promising routes to deliver lithium-ion cells with energy densities that significantly exceed 250 Wh/kg. The capacity decay in the long-term cycling has been attributed to several factors including electrolyte decomposition and cross-talk between the anode and cathode. Forming a stable solid electrolyte interface (SEI) layer at the graphite anode is indispensable preventing irreversible consumption of electrolyte and lithium ions. However, the process to form such passivation layers for lithium ion batteries typically takes several days, or even up to a week, resulting in either lower LIB production rates or excessive capital cost for battery cyclers. In this study, we propose a fast and effective formation protocol that could significantly reduce the formation time for LiNi0.8Mn0.1Co0.1O2 / graphite full cells. We show that cells formed over a reduced time exhibit similar rate performance to cells that undergo a much longer formation protocol. Moreover, better capacity retention after long-term cycling is achieved with the shorter formation time. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and impedance spectroscopy reveal the impact of formation protocol on SEI chemistry and impedance growth. Finally, this study shows that there is an optimal formation time below which severe lithium plating and faster capacity fade are observed. Our study illustrates a viable route to reduce the time and cost to form a robust and chemically stable SEI layer and enable a long cycle life for lithium ion batteries with nickel-rich NMC cathodes.
Sion Power's Licerion
® Batteries
Authors: Mikhaylik Yuriy , Kovalev Igor , Scordilis-Kelley Charlie , Liao Lily , Laramie Michael , Schoop Urs , Kelley Tracy
Published: February 2020

Sion Power known as developer of high energy Li-S battery is extending its new Licerion®
technology to other electrochemical systems including Li - Intercalation Cathodes. The core of Licerion®
technology is protected metallic lithium anode with several levels of physical and chemical protection. Physical protection is based on ceramic-polymer composite membranes and is combined with specialized cell design and electrolyte systems providing smooth, dendrite-free lithium deposition and chemical protection of exposed metallic lithium surface. This approach addresses safety and cycle life problems that have historically plagued lithium metal electrodes. Sion Power Corporation in collaboration with BASF is working aggressively on realizing the impressive potential of the Licerion®

technology. Current state of development offers highest combination of energy density, specific energy and cycle life: exceeding 1000 Wh/L, 500 Wh/kg and over 350 cycles. Sion Power's new Licerion®
technology is a solution beyond Li-Ion and beyond Li-S and offers diverse battery applications from electric vehicles to stratospheric drones and urban air transportation.

This presentation will discuss:

Failure mechanisms of rechargeable batteries with metallic lithium anode.

Approaches pursued by Sion Power in collaboration with BASF towards next generation of Licerion®
- Sulfur and Licerion®
- Ion batteries.

Current status of Licerion®
batteries: their energy, cycle life, high power performance and thermal stability.
Reversibility of Ni-Rich Layered Cathode Material Revealed By Structural, Spectroscopic and Imaging Characterizations
Authors: Hu Enyuan , Shadike Zulipiya , WANG Xuelong , Lee Hung-Sui , Yang Xiao-Qing
Published: February 2020

Ni-rich layered cathode materials are important candidates for lithium-ion batteries used for high energy density applications, such as electric vehicles. However, its capacity fades during cycling, especially when a high cut off charge voltage is applied (>4.4 V). To understand the origin of this capacity fade, comprehensive diagnostic tools are applied to understand their structure, chemical and morphological properties during cycling. X-ray diffraction results show that while the LiNi0.6Mn0.2Co0.2O2 (NMC622) can mostly recover its original structure at fully discharged state, even after 0.95 Li is extracted (charged to 5.2 V), it does undergo slab sliding that leads to stacking fault (O1 type) which does not go away during cycling. In addition, transmission X-ray imaging (TXM) results indicate that cycling can induces Li content inhomogeneity within the particle. As a result, the strain builds up and is directly responsible for the cracking of primary and secondary particles. Hard X-ray absorption spectroscopy (XAS) results indicate that both Ni and Co contribute to the capacity by going through the Ni3+/Ni4+ and Co3+/Co4+ redox couples. A comparison is made between Ni-rich and the Li-rich layered materials, which is well known for the problem of oxygen release. It is found that for the Ni-rich system, the oxidization state of transition metals (bulk) are well maintained during cycling, whereas for the Li-rich system the average oxidization states keep decreasing (lower oxidation states at both fully charged and fully discharged states after cycling than the pristine sample), suggesting at least the bulk of Ni-rich material is robust against oxygen release. Soft XAS that differentiates the surface chemical information from the bulk indicates that inactive rock salt phase is formed during cycling. These results show that cycling induced strain, stacking fault and surface reconstruction are the main issues to be addressed for further improvement of this material.

Acknowledgement

This project was supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies through Advanced Battery Material Research (BMR) program (Battery500 consortium) under Contract No. DESC0012704. This research used resources 8-ID and 28-ID-2 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The authors would also like to acknowledge the use of beamline 6-2c of Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515.
Boron-Doped Ni-Rich Layered Cathodes with Enhanced Cycling Stability
Authors: Park Kang-Joon , Sun Yang-Kook
Published: February 2020

Lithium-ion batteries (LIBs) are emerging as one of the most promising power sources for portable devices, as well as electric vehicles (EVs) and large energy storage systems (ESS), owing to their high energy density and excellent cycle life. However, the application of LIBs in EVs to reduce CO2 emissions in internal combustion engine vehicles (ICEVs) involves some critical technical challenges, such as the driving range, safety, and cost concerns due to the properties of LIBs.1-3 For this reason, research interests and industrial efforts have focused on developing low-cost, high-energy, and safe cathode materials, which are the main component determining LIB performance and cost. Transition metal layered oxides belonging to the LiNixCoyAlzO2 (NCA) or LiNixCoyMnzO2 (NCM) family, which can increase their intrinsic capacity (above 200 mAh g-1) by increasing Ni content, are emerging as promising new cathode materials.4 However, the intrinsic drawbacks of Ni-rich cathodes, such as low Li intercalation stability over extended cycles, should be improved. In this study, we present the first successful boron doping strategy for a Ni-rich cathode material with very high Ni content. For the boron doping, we used a simple method where only a small amount of B2O3 was added during the calcination process. In addition, the structural and morphological stability of the boron-doped Ni-rich NCM cathode material was investigated before and after testing to evaluate the improved electrochemical performance; specifically, the significantly enhanced cycle performance. Thus, we conclude that the boron doping strategy is an effective and simple way to mitigate the poor stability problem of Ni-rich cathode materials for high-energy and stable LIBs.

References

D.-W. Jun, C. S. Yoon, U.-H. Kim, Y.-K. Sun, Chem. Mater.
2017, 29, 5048.

J. H. Lee, C. S. Yoon, J.-Y. Hwang, S.-J. Kim, F. Maglia, P. Lamp, S.-T. Myung, Y.-K. Sun, Energy Environ. Sci.
2016, 9, 2152.

S.-T. Myung, F. Maglia, K.-J. Park, C. S. Yoon, P. Lamp, S.-J. Kim, Y.-K. Sun, ACS Energy Lett.
2017, 2, 196.

4. K.-S. Lee, S.-T. Myung, K. Amine, H. Yashiro, Y.-K. Sun, J. Electrochem. Soc.
2007, 154, A971.