bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrostatically Sprayed Manganese Oxide Films – from Pseudocapacitive Charge Storage Materials to 3D Microelectrode Integrands
Authors: Agrawal Richa , Adelowo Ebenezer , Rabiei Baboukani Amin , Villegas Michael Franc , Henriques Alexandra , Wang Chunlei
Published: February 2020

Electrochemical capacitors or “supercapacitors” essentially bridge the gap between traditional capacitors and rechargeable batteries with their high specific power and moderate energy densities. Commercial supercapacitors typically comprise activated carbon (AC) electrodes, which rely on electrostatic double layer charge storage mechanisms. Pseudocapacitors, on the other hand, benefit from surface redox reactions which lend them superior capacitance than their double layer counterparts. Conducting polymers and transitional metal oxides (TMOs) account for pseudocapacitors in general and among TMOs, manganese oxides have widely been investigated owing to their high specific capacitances, low cost, and environmental benignity. In this work, porous manganese oxide (MnOx) thin films were synthesized via electrostatic spray deposition (ESD) and evaluated as pseudocapacitive electrode materials in aqueous media. Very interestingly, the gravimetric specific capacitance of the ESD based MnOx electrodes underwent a marked enhancement upon electrochemical cycling, from 72Fg-1 to 225Fg-1, with a concomitant improvement in kinetics and conductivity. The change in capacitance and resistivity is attributed to a partial electrochemical phase transformation from the spinel type hausmannite Mn3O4 to the conducting layered birnessite MnO2. Furthermore, the films were able to retain 88.4% of the maximal capacitance after 1000 cycles. Upon verifying the viability of the manganese oxide films for pseudocapacitive applications, the thin films were integrated onto carbon micro-pillars created via carbon microelectromechanical systems (C-MEMS) for examining their application as potential microelectrode candidates. In a symmetric two-electrode cell setup, the MnOx/C-MEMS microelectrodes were able to deliver specific capacitances as high as 0.055 Fcm-2 and stack capacitances as high as 7.4Fcm-3, with maximal stack energy and power densities of 0.51 mWhcm-3 and 28.3 mWcm-3, respectively. The excellent areal capacitance of the MnOx-MEs is attributed to the pseudocapacitive MnOx as well as the three-dimensional architectural framework provided by the carbon micropillars.
Dynamics of Direct Hydrocarbon PEM Fuel Cells
Authors: Kong Eugene HyunJe , Ronney Paul D , Prakash G. K. Surya
Published: February 2020

Hydrocarbons have 50-100 times higher energy per unit weight compared to commercially available batteries, thus harvesting only 10% of the energy from hydrocarbons could provide a far lighter energy source for portable electronic devices. With this motivation, the feasibility of using Polymer Electrolyte Membrane (PEM) fuel cells with propane fuel, operating at low temperatures (< 100˚C), was explored. Nafion® membranes were used as electrolytes and platinum black was used as catalyst. At a catalyst loading of 15 mg/cm2 at anode and 8 mg/cm2 at cathode, a maximum steady-state power density of 7.5 mW/cm2 was observed. However, with hydrazine treatment of platinum black catalyst nearly doubled the power density of propane fuel and increased power by about 50% with hydrogen fuel.

It was interesting to note that there was a significant influence of the current history on the fuel cell performance. In particular, at higher current densities (> 24 mA/cm2) the power output gradually decreases then rapidly “extinguishes” (i.e., produces no power). However, by employing an unconventional operating mode (“load-interrupt”) where the current is shut off for a short period of time and then reapplied, the maximum average power density increased to 11.6 mW/cm2. For dimethyl ether (DME) and hydrogen, no significant effect of current history was observed.

It is proposed that the fuel cell “extinction” is associated with the formation of inactive intermediate species on the anode, blocking active sites. A simple model was developed in an effort to interpret “extinction” behavior. This model assumes all sites are in either an “active” or “inactive” state with heuristic kinetic relations to describe the rates of conversion of active to inactive sites and vice versa. This model was found to be in good qualitative agreement with the experiments when the rate of formation of inactive sites was proportional not only to the number of active sites but also the number of already-inactive sites, i.e. in a self-accelerating manner. Possible physical mechanisms for this heuristic model are discussed.
Combined Economic and Experimental Evaluation of Energy Storage for Grid Applications
Authors: Davies Daniel m , Verde Michael , Mnyshenko Oleksiy , Chen Ying-Ru , Rajeev Rohan , Meng Shirley , Elliott Graham
Published: February 2020

Batteries will undoubtedly play critical roles in modernizing energy grids, allowing greater penetration of renewable generation and providing services that help grids function. Applying storage technology to grid applications is a business decision that requires potential revenues to be accurately measured to determine economic viability. Using models of storage connected to the California energy grid, we simulate grid-scale applications to estimate such revenues under current market conditions. All calculations are undertaken over two full years of operation of the storage device where a simulation of the grid-connected battery is undertaken so that control and decision are made in real time. Control and decision are made with data available at the time and mimics actual use as it might have happened. The use of a long period of data provides precise estimates as to the values of different applications of the battery. Each simulation results in duty cycles (power profiles) on which the cell-level batteries are tested. We examine the effects of these differing duty cycles on the efficiencies of batteries with various chemsitries. For the first time, we reveal critical tradeoffs between the battery chemistries and the applicability of their energy content, and show that accurate revenue measurement can only be achieved if realistic battery operation in each application is taken into account. The findings in this work could call for a paradigm shift on how the true economic values of energy storage devices could be assessed.
The Design and Construction of Integrated Si-Based Proton Exchange Membrane Fuel Cells (PEMFCs) with Improved Performances
Authors: Li Jing
Published: February 2020

Given the high power density and environmentally friendly, e.g. low emission and noise, proton exchange membrane fuel cells (PEMFCs) have been considered to be promising in applications to transportation, combined heat and power (CHP) systems and portable electronic devices.[1-4] Therefore, new strategies are highly demanded to keep promoting the performance enhancement and device integration in more compact manner. In this work, novel designs of the miniature flow fields and integrated PEMFCs were realized on Si wafers. In order to maintain the good mass/electron transfers for sufficient and efficient electrochemical conversion of the fuel, the vertical dot-type flow fields were fabricated by template-assisted dry etching cooperating with the dicing and deposition of Cr/Au conducting layers. Eventually, the integrated Si-based PEMFC were constructed by combining the commercial Pt/C catalysts (the load of Pt was 0.2 mg/cm2) and carbon black as gas diffusion layer (GDL) within the Si-based flow fields, in which a highest peak power of 354 mW/cm2 was accomplished. This work proposed a unique design and Si-compatible processing of the integrated FCs, which may present potential industrial applications.
Selective Ion Removal from Water Using Flow-through Electrode Capacitive Deionization (fteCDI)
Authors: Campbell Patrick G. , Hawks Steven A , Cerón Maira R. , Pham Tuan Anh , Shea Patrick , Wood Brandon C. , Stadermann Michael
Published: February 2020

Capacitive deionization (CDI) removes ions from solution using charged electrodes. CDI has demonstrated significant energy savings compared with reverse osmosis for removal of salt from brackish water. By tailoring electrode properties such as pore morphology and surface functionality, as well as cell operating parameters, selective separation of ions can be achieved (e.g., selective absorption of nitrate in the presence of chloride and sulfate ions). The selective removal of toxic ions from otherwise potable water has the potential to dramatically reduce the cost of water treatment. Here, we will present the latest work from Lawrence Livermore National Laboratory on selective ion removal using our unique flow-through electrode CDI platform, including the development of a multi-scale model (FE + QMD) to help elucidate the mechanism(s) for ion selectivity in CDI.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Measurements and Simulations of Lithium Isotopes Concentration Fluxes during Electrolytic Lithium -7 Enrichment
Authors: Sarswat Prashant , Free Michael L , Zhang Zongliang
Published: February 2020

Isotopes are utilized in many applications, including physical science analyses, food preservation, archaeology, biology, medicine, pharmaceuticals, national security, and agriculture. The purity is a key requirement for the isotope use. Many different technologies have been used to enrich and separate isotopes. Lithium isotope separation techniques are not very efficient and hence the supply of 7Li is limited. Natural lithium contains a mixture of the two isotopes 6Li and 7Li with abundances of ~ 7.5% and 92.5%, respectively. 7LiOH is often utilized for pH control in pressurized water reactors in the nuclear power industry. The effective separation can be improved to produce purified 7Li or 7Li enriched salt by careful control of diffusion and migration of these isotopes that differ due to their different atomic mass. A systematic study was conducted using computational and experimental techniques for achieving enhanced, environmentally friendly, and reliable 7Li production techniques.
Alkaline Plating and Striping of Metal-Amine Complexes for Amine Regeneration in Gas Scrubbing Processes
Authors: Wang Miao , Hariharan Subrahmaniam Bharadwaj , Massen-Hane Michael Edward , Shaw Ryan , Hatton T. Alan
Published: February 2020

Traditional thermal amine gas scrubbing technology can be energy and capital intensive owing to the enthalpy of formation of amine-CO2 complexes and the complexity in the process integration of a stripper column. An electrochemically mediated amine regeneration cycle in traditional gas scrubbing process has been proposed for post combustion CO2 capture.1
2 We take the advantage of competitive binding of amine with electroactive species, e.g. copper, to facilitate the desorption of CO2 and regeneration of amine in a modular electrochemical reactor.3 We investigated the energy efficiency of this electrochemical process via bulk electrolysis of the electrolyte. The charges applied in electrochemical metal dissolution are compared quantitatively to gas desorption in the electrolyte. Our controlled volume analysis validates the efficacy of the proposed cycle. We benchmarked the polarization of metal electrodes with different metal-amine complexes using a rotating disk electrode. The Tafel expression of the kinetic data assists in gauging the rate of metal dissolution/plating and provides insight into effects of various anions. We examined the quality of metal deposits at different operating conditions using XPS. The surface composition of the electrodes account for long-term stability of the electrodes. These thermo and kinetic data afford qualitative comparison of cell-level performance in the amine regeneration cycle.

References:

M. C. Stern, F. Simeon, H. Herzog, and T. A. Hatton, Energy Environ. Sci., 6, 2505 (2013) http://xlink.rsc.org/?DOI=c3ee41165f.

M. C. Stern and T. A. Hatton, RSC Adv., 4, 5906 (2014) http://xlink.rsc.org/?DOI=c3ra46774k.

N. Jemaa, H. J. Walls, R. D. Noble, D. E. Wedman, and C. A. Koval, AIChE J., 39, 867–875 (1993).
(Invited) Toward Wireless Biosensing Using Transparent Graphene Electronics
Authors: Chen Pai-Yen , Cheng Mark Ming-Cheng
Published: February 2020

We present a new type of self-powered, low- interference wireless sensors based on graphene circuits, which can have dual functions: chemical sensing at the molecular level and radio-frequency (RF) modulation. . We have designed two different types of circuits comprising back-gate graphene field-effect transistors (GFETs) and compared in detail their performance and implementation complexity. We have also proposed a reliable readout method based on the machine learning for extracting the mean value and the fluctuation of chemical doping levels in GFETs. We demonstrate that a fully passive, graphene-based harmonic (transponder) sensor can display a chemically sensitive frequency multiplication effect, which, when linked to a hybrid-fed small antenna, can realize an ultrasensitive, low-profile, light-weight, and potentially flexible RF sensor.
(Invited) Use of Discrete Liquid-Solid Contact Electrification As Ways of Self-Powered Sensing
Authors: Kim Dong Sung
Published: February 2020

In this presentation, the concept of “discrete liquid-solid contact electrification”, which is result of sequential process of the liquid contact on the solid surface and successive detachment of contact liquid from the solid surface, is reported. After the first report on discrete liquid-solid contact electrification inside the conventional pipet tip surface, the phenomenon is deeply investigated and explored with the help of utilization on a hydrophobic surfaces, which enables easy detachment of liquid from its surface. As a result, the phenomenon can be intentionally suppressed and/or enhanced.

Recently, discrete liquid-solid contact electrification has been utilized as a fundamental operation mechanism of the self-powered sensor, which utilizes the contact electrification phenomenon with electrical induction to efficiently convert ambient mechanical energy to electrical energy. In this paper, the fabrication of the self-powered sensor utilizing discrete liquid-solid contact electrification is introduced to help its understanding.

With the fact that ordinary pipetting procedure always involves spontaneous discrete liquid-solid contact electrification resulting in generation of net electrical charges on the inner surface of the polymeric pipet tip, in this study, a concept of a smart pipet tip is newly proposed to evaluate the electrolyte concentration of the dispensed solution. The smart pipet tip possessing triboelectricity and thermoelectricity detecting modules is advantageous as it performs in situ evaluation of solution characteristics without any subsidiary solution handling process. The spontaneously generated electric signals are intensively investigated with the theoretical analyses. The proof-of-concept demonstration of the present smart pipet tip is shown for in situ prediction of morphology of nanoparticles during their synthetic reaction, which critically determines their catalytic activity. The present study would broaden the applications of discrete liquid-solid contact electrification, which is ubiquitous but previously inconspicuous in our daily life.
Development of Thermal Nanoimprinting Process for the Fabrication of Tailored-Triboelectric Nanogenerator
Authors: Yoo Donghyeon , Choi Dongwhi , Kim Dong Sung
Published: February 2020

Recently, triboelectric nanogenerator (TENG), working based on triboelectric effect and electrical induction, emerge as one kind of energy harvesting technology. The TENG is mainly composed of dielectric layer where frictional contact occurs and conductive layer where current flows. Because of the characteristic of triboelectric effect, strategies to make efficient TENG are focused on material selection and effective contact area increment. Given materials, micro/nanostructure fabrication corresponds to the latter strategy. Several fabrication methods are already reported such as surface etching with nanoparticle and surface replication, but they require high fabrication cost. Furthermore, they need additional process such as integration micro/nanotophographical layer with conductive layer, resulting in a multistep fabrication. The fabrication environment hinders high productivity and commercialization of TENG.

In this study, we used thermal nanoimprinting to fabricate a transparent and flexible TENG named a Pattern Assisted TriboElectric Replicable Nanogenerator (PATERN). From the method, we can achieve nanostructure replication and integration with conductive layer simultaneously, which are two essential steps to fabricate high performance TENG. The fabrication cycle was within 6 min. The PATERN has maximum transmittance about 88% at the 850-1600 nm range, and bending radius about 3.2 mm. From modifying the shape of electrode layer, we can also achieve a bi-directional mechanical energy harvesting ability, which is essential for efficiently harvest the energy from complex real mechanical motions. Given that TENG can be cost-effectively fabricated by utilizing conventionally available films (less than $1) with fast fabrication process, we believed the technology lead a new concept of disposable TENG and its accompanying application, such as hybrid energy harvester or biomechanical energy harvester.

Figure 1
(Invited) Photodetection from Mid-IR to UV Using Semiconductor Heterostructures
Authors: Wu Tom
Published: February 2020

I will discuss the use of semiconductor heterostructures with proper bandgaps and architectures to detect photons with different wavelengths. First, for the most pursued visible light detection, hybrid perovskites have aroused lots of interest because of their exceptional properties, such as low-cost solution processing, tunable direct bandgap, high light absorption and long carrier diffusion length. Our experiments demonstrate that combining 3D perovskites with high-mobility 1D carbon nanotubes or 2D two-dimensional metal dichalcogenides significantly enhances charge transport and device performance. Second, we demonstrate a mid-infrared hybrid graphene photodetector enabled via coupling graphene with a narrow bandgap semiconductor Ti2O3. This hybrid photodetector achieves high responsivity of ~200 A/W in a broadband wavelength range up to 10 μm. Finally, using epitaxial ferroelectric/semiconductor junctions with a current-perpendicular-to-plane geometry, we achieve a colossal X-ray-induced photoconductivity with a magnitude of six orders. This X-ray-induced persistent photoconductivity persists for days with negligible decay. This new device scheme open a new route towards X-ray sensing and imaging applications.
Electrochemical UV Sensor Using Carbon Quantum Dot/Graphene Semiconductor
Authors: Wang Yuxuan , Myers Morgan , Staser John A.
Published: February 2020

Skin cancer is a pressing public health issue, especially in rural communities like Appalachia.1 Increasing public awareness about the risk of exposure to UV radiation and its correlation to the prevalence of skin cancer could change public behavior in a positive way. Such behavioral changes could ultimately reduce the rate of skin cancer and directly address public health.

Wearable UV sensors that provide easy-to-understand, accurate and reproducible results is one possible avenue to impact public awareness and behavior. Our group has developed nitrogen-doped carbon quantum dot/graphene (N-CQD/graphene) photoactive electrodes that generate a sustained photocurrent upon illumination with UV radiation.

The sensor consists of the N-CQD/graphene photoactive electrode and a nonphotoactive graphene electrode sandwiching a Nafion® polymer electrolyte membrane. Critically, the magnitude of the photocurrent response is proportional to the intensity of the incident UV radiation.2

Incorporating the photoactive electrode into a sensor using a solid polymer electrode could lead to flexible UV sensors ideal for wearable applications by the general public.

This presentation will detail synthesis and evaluation procedures for the electrochemical UV sensor. We will discuss current limitations that must be overcome before such a wearable device can be made technically feasible.

[1]. Appalachia Community Cancer Network. Addressing the Cancer Burden in Appalachian Communities, 2010. Retrieved from http://www.accnweb.com/pages/cancer-burden-app.pdf

[2]. Y. Wang, M. Myers and J.A. Staser, J. Electrochem. Soc., 164: H3001-H3007 (2018).
(Invited) Electrical Energy Generation Via Reversible Chemical Doping on Carbon Nanotube Fibers – a Wearable All-Carbon Voltage Generator
Authors: Liu Albert Tianxiang , Kunai Yuichiro , Liu Pingwei , Kaplan Amir , Cottrill Anton , Strano Michael S
Published: February 2020

Chemically modified carbon nanotube fibers enable unique power sources driven entirely by a chemical potential gradient. Electrical current (11.9 μA mg−1) and potential (525 mV) are reversibly produced by localized acetonitrile doping under ambient conditions. An inverse length-scaling of the maximum power as L−1.03 that creates specific powers as large as 30.0 kW kg−1 highlights the potential for microscale energy generation. We demonstrate that this Asymmetric Chemical Doping (ACD) electricity induction method can be scaled using a printing/patterning technique for the carbon nanotube fiber generators. This allows us to develop a conformable carbon based voltage generator that can be grafted onto human skin in a facile manner.

Reference: Advanced Materials, 2016, 28, 9752-9757
Mg-Ion Battery Electrode: An Organic Solid’s Herring Bone Structure Squeezed upon Mg-Ion Insertion
Authors: Rodríguez Pérez Ismael Antonio , Yuan Yifei , Bommier Clement , Wang Xingfeng , Ma Lu , Leonard Daniel Philip , Lerner Michael M. , Carter Rich G. , Wu Tianpin , Greaney P. Alex , Lu Jun , Ji Xiulei
Published: February 2020

We report that crystalline 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), an organic solid, is highly amenable to host divalent metal ions, i.e., Mg2+ and Ca2+, in aqueous electrolytes, where the van der Waals structure is intrinsically superior in hosting charge-dense ions. We observe that the divalency nature of Mg2+ causes never-reported unique squeezing deformation of the electrode structure, where it contracts and expands in different crystallographic directions when hosting inserted Mg-ions. This phenomenon is revealed experimentally by ex situ x-ray diffraction and transmission electron microscopy, and is investigated theoretically by first-principles calculations. Interestingly, hosting one Mg2+ ion requires the coordination from three PTCDA molecules in adjacent columns of stacked molecules, which rotates the columns, thus reducing the (011) spacing but increasing the (021) spacing. We demonstrate that a PTCDA Mg-ion electrode delivers a reversible capacity of 125 mA h g-1, which may include a minor contribution of hydronium storage, a good rate capability of retaining 75 mA h g-1 at 500 mA g-1 (or 3.7 C), and stable cycle life. We also report Ca2+ storage in PTCDA, where a reversible capacity of over 80 mA h g-1 is delivered.
Slurry Model for Understanding Fabrication of Li-Ion Battery Electrodes
Authors: Nikpour Mojdeh , Cordon Joshua , Wheeler Dean R. , Mazzeo Brian
Published: February 2020

Battery performance in part relies on the microstructure of each electrode, which is determined by the electrode composition and fabrication process. Accurate and direct experimental measurement of electrode properties is challenging due to the thickness of electrode films (30-80 µm), yet those properties are needed to generate cell-level performance models and to improve manufacturing processes. Therefore, a realistic microstructure prediction model is necessary for designing and manufacturing better batteries. In our model, we consider all the fabrication steps that would determine the final electrode microstructure in a predictive fashion.

We are not aware of any prior slurry models that can simulate the multi-phase nature of the Li-ion electrode fabrication process. We have been developing a series of particle-based microstructure models using LAMMPS (a particle simulator) [1]. In the most recent model, the governing equations are based on the smooth particle hydrodynamics (SPH) method. The major benefit of SPH is its Lagrangian formulation of the Navier-Stokes equations that would eliminate the need for mesh in our simulation.

We propose a model that imitates the microstructure of a commercial electrode like Toda NMC 523 in terms of composition and active material particle shapes (based on SEM images). We consider each component as a clump of a certain number of particles with a certain size; we also assign density, smoothing length and viscosity as the factors that would affect the interaction between particles.

In this presentation we will discuss the new model, including validation efforts. We use fluid viscosity, interactions between particles, and interfacial behavior as some indicators of our model accuracy. We also will show how the model predicts coating behavior in a slot die coating process. Our hope is to also use the model later to predict behavior during the drying and calendering steps, leading to the final microstructure of the film. The completed model will be used to explore the factors that create such microstructure and how we can control them to manufacture better batteries.

Figure 1: Simulation box model of slurry containing Toda 523; carbon domain is red, active material is yellow, and solvent particles are blue.

Reference

[1]
M. Forouzan et al., J. Power Sources 312, 172-183 (2016).

Figure 1
A Binder-Free Snowflake Grown Microcube Prussian Blue Particles As Possible Electrode for Supercapacitor and Sodium Ion Battery Applications
Authors: vijaya Sankar Kalimuthu , Seo Youngho , Jun Seong Chan
Published: February 2020

For constructing high energy storage devices, designing of electrode materials with high performance is a great challenge for the past decades. So far, various materials were employed as suitable electrode for supercapacitor and sodium ion batteries. Such as nickel, cobalt, tin, vanadium, ferrite and bismuth oxides/hydroxides/sulfides/phosphide/nitrides, conducting polymers, 2D-materials and its composites are subjected as possible electrode materials. However, limited reports are available for anode materials for energy storage applications. Recently, the Prussian Blue has received more attention because of its wide applications in various fields. Herein, a binder-free Prussian blue is synthesized by a facile hydrothermal method and employed as anode, for the first time to our knowledge. The x-ray diffraction and Fourier transform infrared spectroscopy results reveals that the single and phase purity of the sample. The microscopic image reveals that the snowflake grows from microcupe, which more favor for large energy storage. The Prussian Blue exhibited the maximum specific capacitance (166 mF cm-2 at 5 mV s-1) and good lifespan over 5000 cycles in 1MKOH electrolyte. Likewise, the Prussian Blue tested as anode for sodium ion battery and delivered the specific capacity of 250 mAh g-1 (first cycle) at a current of 1 mA. Our results suggest the novel design of materials holds a great promise for potential application toward next-generation energy storage.

Figs. 1 represent the FESEM images of Prussian Blue at different magnifications.

Figure 1
Rate Performance of Silicon Alloy in Blended Lithium-Ion Battery Anode with Graphite
Authors: Cao Lei , Yang Chuanbo , Santhanagopalan Shriram
Published: February 2020

Incorporation of silicon based materials to graphite anode has been a promising strategy to boost anode specific capacity. Due to the distinct difference between open circuit potential (OCP) of the two material, participation of silicon alloy was in later stage of delithiation under slow C-rate condition, as shown by our previous study. 1 The present work expands silicon alloy contribution study into C-rate performance combing both experimental and Multi-Scale Multi-Dimensional modeling2 efforts. Diffusion overpotential drastically increases at high C-rates as diffusion coefficient of silicon alloy is smaller by one to two orders of magnitude than that of graphite1. We are able to track evolution of Si alloy exchange current density along charging and discharging process, and quantify contribution of silicon alloy in different C-rates. A critical C-rate level is also suggested, depending on blending ratio with graphite, beyond which enhancement of silicon alloy is diminished.

Cao, L.; Yang, C.; Santhanagopalan, S.; Inman, K.; Pesaran, A., Evaluation of Silicon Alloy Contribution in Blended Lithium-Ion Battery Anode with Graphite. Meeting Abstracts
2017,
MA2017-01 (1), 27.

Kim, G.-H.; Smith, K.; Lawrence-Simon, J.; Yang, C., Efficient and Extensible Quasi-Explicit Modular Nonlinear Multiscale Battery Model: GH-MSMD. Journal of The Electrochemical Society
2017,
164 (6), A1076-A1088.
Fundamental Investigations into Na+ Behavior in Aqueous and Non-Aqueous Electrolytes
Authors: Cresce Arthur v. , Borodin Oleg , Rogers Reginald , Xu Kang
Published: February 2020

Sodium ion batteries present a meaningful opportunity to apply knowledge gained from lithium ion batteries. In order to produce functional sodium ion batteries that present real advantages compared to today’s commercial lithium ion batteries, the sodium ion and its interactions in solution must be exploited. From previous work on the subject, our work has shown fundamental differences in the solvation of Na+ as compared to Li+. Specifically, we were able to show that Na+ experiences weaker attractive forces and longer bond lengths between itself and its solvent molecules in organic and aqueous solution, which affects contact ion pairing and aggregation behavior. In this work, we will explore the relationship between ion-solvent interactions as they relate to the transference number and electrochemical stability of sodium organic and aqueous electrolytes. Ion interaction has a significant effect on the reduction potential of both solvent molecules and anions, and so there may be opportunities to take advantage of Na+ to affect both transference number and stability with the goal of producing effective electrolytes for sodium ion batteries.
Tailoring the Kinetics of Sn Anodes for High Power Energy Storage Devices
Authors: Cui Jiang , Yao Shanshan , Kim Jang-Kyo
Published: February 2020

Alkali ion batteries, such as Li-ion batteries (LIBs) and Na-ion batteries (NIBs), have recently drawn much attention due to their high energy densities, high Coulombic efficiencies and low self-discharge rates, making them useful in electronics, electric vehicles and grid-scale energy storage. One of the major obstacles to widespread applications of these rechargeable batteries, however, is their poor electrochemical performance under high power densities. The obstacle is attributed to the sluggish electrochemical kinetics, including slow diffusion rate of alkali ions in solid electrodes, low electrical conductivity and undesired phase transformation. Sn-based anodes having both high gravimetric and volumetric capacities are considered a promising candidate for next-generation LIBs and NIBs, but they also face the same challenge. Herein, we demonstrate that the electrochemical kinetics of Sn-based anodes, such as SnO2 and SnS2, can be largely enhanced by amorphization, doping of heteroatoms and facilitating the pseudocapacitive charge storage. The mechanistic insight of the enhanced kinetics is revealed by combining the electrochemical measurements with in situ TEM characterization and the first-principles calculations. Thanks to the new findings, we successfully fabricate Sb-doped SnO2/graphene-CNT aerogel anodes which deliver a high areal capacity of 2.6 mAh cm-2 at a high current density of 8 mA cm-2 in LIBs. The Na hybrid capacitor consisting of an activated carbon cathode and a SnS2/graphene-CNT aerogel anode is further developed for applications requiring high power densities and low costs. The as-assembled hybrid capacitor delivers an exceptional energy density of 26.9 Wh kg−1 at an ultrahigh power density of 6053 W kg−1. The implications of these discoveries for both fundamental understanding and practical applications are discussed.

References:

[1] J. Cui, S. Yao, J.K. Kim, Energy Storage Mater. 7 (2017) 64-114.

[2] J. Cui, Z.L. Xu, S. Yao, J. Huang, J.Q. Huang, S. Abouali, M. Akbari Garakani, X. Ning, J.K. Kim, J. Mater. Chem. A 4 (2016) 10964–10973.

[3] J. Cui, S. Yao, J.Q. Huang, L. Qin, W.G. Chong, Z. Sadighi, J. Huang, Z. Wang, J.K. Kim, Energy Storage Mater. 9 (2017) 85-95.

[4] J. Cui, S. Yao, Z. Lu, J.Q. Huang, W.G. Chong, F. Ciucci, J.K. Kim, Adv. Energy Mater. (2017) 201702488.
Flame Made Nanopowder Processing Results in Low Temperature Sintering of β'’-Al2O3 Thin Films (50 µm) with TiO2 and ZrO2 Addition
Authors: Laine Richard , Yi Eongyu , Temeche Eleni
Published: February 2020

β’’-Al2O3 is used commercially as a Na+ conducting ceramic electrolyte for its high ionic conductivity (0.2-0.3 S cm-1 at 300°C) and low materials’ costs. However, for batteries using β'’-Al2O3, about half of the cell resistance arises from the electrolyte itself because traditionally processed electrolyte materials are 1-2 mm thick. One can anticipate dramatic drops in cell resistance at <100 µm. However, traditional high sintering temperatures of 1600 °C/0-4 h cause rapid and excessive Na2O loss driving formation of the β- rather than β'’-Al2O3 phase lowering ionic conductivities limiting final properties. Known methods of β'’-Al2O3 sintering commonly involve covering the sample with the same powder to reduce Na2O loss. The quality (phase, particle size, particle morphology, etc.) of the starting powder has been shown to have a strong effect on β’’-Al2O3 sintering behavior.

In line with our latest success of using flame made nanopowders (NPs) to minimize the external energy input for sintering Li7La3Zr2O12, Li+ conducting ceramic electrolyte known for its difficulty in sintering, we show that the same can be achieved for β’’-Al2O3. In this study, β’’-Al2O3, TiO2 and ZrO2 NPs were produced by liquid-feed flame spray pyrolysis (LF-FSP). The NPs were then processed to green films (80 µm) by tape casting such that β'’-Al2O3 with 0, 1, 2, and 3 wt.% of TiO2 addition is produced. TiO2 was selected to aid sintering as Al3+ vacancies generated by Ti4+
doping promote the sintering process. Furthermore, low melting point (1050-1150 °C) Na2O-TiO­2 line compounds form inducing liquid phase sintering.

As expected, superior densification of β'’-Al2O3 films occurs with increasing TiO2 wt. %. Near full densities are reached at ≥ 1360 °C/2 h with 2 and 3 wt. % added TiO2. However β’’-Al2O3 content reaches only ~65 wt.% and the orientation of the c-axis is perpendicular to the film surface per XRD. The preferred conduction plane is perpendicular to the c-axis reducing net conductivity. Also, the large grain sizes seen in the 2 and 3 wt. % TiO2 samples suggest liquid phase sintering. To perturb grain reorientation during liquid phase sintering, and also pin grain boundaries to reduce grain growth, we introduced 10 wt. % of ZrO2 with 2 and 3 wt.% TiO2. The added ZrO2 may also reduce Na2O loss rate by reducing surface exposure of β’’-Al2O3.

Sintering of the aforementioned samples both reduces final grain sizes and degrees of c-axis orientation. Furthermore, nearly full densities could be accessed at 1320 °C/2 h with 85 wt.% β'’-Al2O3. Ionic conductivities obtained equal those reported by others. Our approach is scalable and economical for mass producing β'’-Al2O3 films. Furthermore, the combination of nanopowders with selected additives allows sintering β'’-Al2O3 at 1320 °C, the lowest ever reported.

Work supported on NSF subcontract from Na4B to University of Michigan and by a give from Mercedes-Daimler.
Highly Stable Sodium Metal Batteries Enabled By High Efficiency Electrolytes
Authors: Zheng Jianming , Chen Shuru , Zhao Wengao , Engelhard Mark H , Zhang Jason
Published: February 2020

Lithium ion batteries (LIBs) have been widely applied in consumer electronic devices and are currently expanding their applications in electric vehicles (EVs). However, the increasing concern about the limitation of Li resources has stimulated the development of alternative energy storage systems. In this regard, sodium (Na) ion batteries (SIBs) are now emerging as a promising alternative to LIBs, due to the natural abundance of Na resources. In recent years, a lot of researches have been focused on the identification of non-graphitic carbonaceous anode materials as anodes for SIBs, but the working voltage of those anodes is mostly well above that of the Na/Na+ couple, leading to a lower battery operating voltage and hence a much lower energy density in comparison with LIBs. The direct use of Na metal as a battery anode would therefore be highly advantageous as it exhibits the highest specific capacity (1165 mAh g-1) and the lowest redox potential (-2.714 V vs. standard hydrogen electrode) in SIB system. However, a critical challenge that still hinders direct use of Na metal as anode for sodium metal batteries (SMBs) is the high reactivity of Na metal with electrolytes, which primarily leads to the low coulombic efficiency (CE) of Na depostion/stripping and the poor cycling of SMBs. Here, we report the high rate, high efficiency operation of SMBs using a novel electrolyte using sodium bis(fluorosulfonyl)imide (NaFSI) salt. The electrolyte with 1.5 M NaFSI has been demonstrated to ensure the dendrite-free Na deposition with high CE of > 99%, and fast-charging (20C) and long cycle life (95% retention after 10,000 cycles) of SMBs. More details about this investigation will be provided and discussed in this presentation.
Improving the Electrochemical Properties By Adding a Catalyst-Embedded Interlayer in the Lithium Sulfur Batteries
Authors: Cho Sung Ho , Yoon Woo Young
Published: February 2020

Lithium Sulfur (Li-S) battery has a theoretically high specific capacity of 1675 mAh/g, which one of the most promising energy source for electric vehicles (EVs), hybrid electric vehicles (HEVs). However, Li-S batteries have problems resulting from the polysulfides dissolution into the electrolyte, volumetric extension of sulfur and insulating property of elemental sulfur. These causes make the loss of active materials and the capacity fading phenomenon. Previous studies show adding the interlayer is a simple and effective way for improving electrical performance of lithium sulfur batteries. In this research, we synthesize the catalyst-embedded interlayer by using catalyst-synthesized multi-walled carbon nanotubes. To confirm the catalyst on the multi-walled carbon nanotubes, transmission electron microscopy and X-ray diffraction are used. Cells were tested at the current densities of 0.2 C-rate with 1.7V to 2.8V. The electrochemical properties of catalyst-embedded interlayer are improved rather than the pristine cell.
Sulfone-Based Electrolytes for Highly-Efficient and Stable Lithium Metal Anode
Authors: Ren Xiaodi , Chen Shuru , Engelhard Mark H , Burton Sarah D , Li Qiuyan , Ding Michael S , Schroeder Marshall , Alvarado Judith , Xu Kang , Liu Jun , Zhang Ji-Guang , Xu Wu
Published: February 2020

Lithium (Li) metal batteries (LMBs) have been regarded as a very promising next-generation energy storage system because of the high theoretical specific capacity, the lowest electrochemical potential and the very low gravimetric density of the Li metal anode. Electrolytes that have high Li metal Coulombic efficiency (CE) and high anodic stability on cathodes play a major role to enable the long-term cycling stability of LMBs. Sulfones are known for their high dielectric constants, low flammability and good oxidation stability, but their application in LMBs is restricted due to their poor compatibility with Li metal anode. Uncontrolled Li platting can result in poor Li CE and induce battery short-circuit. Moreover, their high viscosity and poor wettability towards electrodes and separators are serious issues for practical applications. Here, we demonstrate that nodule-shaped instead of dendritic Li deposition and stable Li plating/stripping cycles can be achieved in concentrated sulfone-based electrolytes with a high CE over 98%. Furthermore, with the addition of selected co-solvents, not only the Li metal CE can be further improved, but also the viscosity and wettability issues are solved, enabling high rate Li||NMC cells cycling at a wide temperature range. As a result, improved cycling performance of Li||NMC cells using sulfone-based electrolytes has been realized.
Stable and Dense Sodium Metal Deposition Using a Fluorination Solvent Containing Electrolyte with a 1 M Salt Concentration
Authors: Lee Yongwon
Published: February 2020

Extensive academic and industrial efforts have been dedicated to developing battery-based energy storage technologies with high energy density, low cost, long cycle life, high energy efficiency, and ease of deployment in daily life. In particular, for large-scale electrical energy storage, attention has shifted to sodium (Na) metal batteries owing to the highest specific capacity and the lowest redox potential of metallic Na and the natural abundance of Na resources. Nevertheless, the exceedingly high electrochemical and chemical reactivity of Na metal electrodes toward organic liquid electrolytes and severe Na dendrite formation limit their commercialization. Since most Na deposition occurs at the interface between the anode (or the current collector) and the electrolyte, the discovery of a stable electrolyte is essential for utilizing Na metal anodes in practical applications. In this study, we demonstrate that fluorination solvent containing electrolyte dramatically enhances the reversibility of Na plating and stripping reactions in Na/Cu cells, realizes dense Na deposition, and leads to improved cycling stability at high current densities. By examining the detailed mechanism of the novel electrolyte system, we have found that the interfacial layer contains NaF, which has a high shear modulus and enhances the mechanical integrity of the interlayer by the attractive interaction between the F- ions and Na+ ions of ionic compounds such as Na2CO3 and sodium alkylcarbonates (NaO2CO-R-), resulting in the formation of mechanically strong and ion-permeable interlayers that suppress uncontrolled Na metal plating. The discovery of this work represents a step forward in the electrolyte design of Na metal anodes.
Development of Transparent Secondary Zinc Air Batteries with Extreme Mechanical Robustness
Authors: Kwon Oh Chan , Hwang Ho Jung , Ji Yunseong , Jeon Oksung , Kim Jeong Pil , Lee Chan Min , Shul Yong Gun
Published: February 2020

The dynamics and trends of the portable electronics market drives researches to develop energy sources with newer properties. The advancement of augmented reality has opened windows of opportunities for optical modification of batteries to be implemented in transparent devices similar to the heads-up display. While realization of products is still in its infant ages, it is without question that technology will pursue such directions. Zinc air batteries hold numerous strongholds that advertise itself as the post lithium ion technology. The system’s abundant energy density along with advantages such as cheaper materials cost and environmentally friendliness has prompted this study to further investigate its potentials.

In this presented work, we report the first ever fabrication of transparent secondary zinc air batteries. The system utilizes a commercial transparent stainless-steel mesh as the current collectors. Owning to the unique structure of the battery, the cell exhibits extreme mechanical versatility as free bending without tariffing the cell performance is possible. The average transparency in the visible light region was recorded at 48.8%. Electrochemical analysis revealed stable galvanostatic discharge-charge cycle operations, exceeding more than 100 turnovers for every bended angle. Electrochemical Impedance Spectroscopy results observed minimal deviation between the conformational states.

This research’s potential lies in the simple technique to achieve optical properties in power sources that can be extended to further areas. Mass scale production is also opportunistic as the process utilized are favorable enough for large productions.
Initial Formation of the Solid Electrolyte Interphase in Li Metal Batteries
Authors: Kasse Robert M , Geise Natalie R , Toney Michael F
Published: February 2020

Advances in energy storage technology beyond traditional lithium ion battery (LIB) materials are necessary to meet future energy demands. These include the growing number of electric vehicles and grid storage applications. Next generation technologies such as Li-S and Li-O2 batteries employ metallic lithium as an anode material due to its high specific capacity and low electrochemical potential. However, lithium presents a number of challenges including uncontrolled electrolyte consumption, formation of dendrites and “dead” lithium, as well as formation of a non-passivating and inhomogeneous solid electrolyte interphase (SEI). The composition, morphology, and electrical properties of the SEI are critical to overall battery performance and lifetime. Nevertheless, there exists a lack of fundamental understanding regarding its initial formation and how these early processes relate to cell performance after many cycles.

In this work, we use soft X-ray absorption spectroscopy (XAS) and electrochemical measurements to study the initial stages of SEI formation in Li-Cu cells as a function of cycling parameters in different electrolytes. Using these methods, the potential and rate dependence of electrolyte decomposition and the corresponding SEI formation is illuminated and the effects on initial Li metal plating are investigated. Further, the continued evolution of the SEI during the first several plating and stripping half cycles is studied. Controlled formation of the SEI during the first several half cycles may lead to large effects on the long-term composition and structure of the SEI and determine overall battery performance and cycle life.
DFT Analysis of N2 Electroreduction Kinetics at the Electrode-Electrolyte Interface
Authors: Janik Michael John , Rostamikia Gholamreza , Li Yawei , Maheshwari Sharad
Published: February 2020

Active and selective nitrogen electroreduction is challenged by the need to activate the inert N-N triple bond and the competition with hydrogen evolution. Density functional theory has been used to argue that metal surfaces will inherently be non-selective and offer large overpotentials, due to scaling relationships that correlate all intermediate binding energies with a metal’s N adsorption energy [1-2]. In this talk, we will apply DFT to investigate the elementary kinetics of N2 reduction on metal and metal-oxide surfaces. We will consider elementary kinetics across late transition metal surfaces to examine how the inclusion of kinetic consideration alters the trade-offs between the ability to activate N2 and to reduce eventual NHx species to ammonia. We then consider how electrolyte composition, including proton-transfer co-catalysts, alter the kinetics of reduction of surface bound intermediates on metal surfaces. We apply ab initio thermodynamics to determine the stability of oxide surfaces under N2 reductions, then examine the elementary steps on the (partial reduced) oxide surfaces. We will present possible mechanistic avenues to using metal oxides and electrolyte/surface additives to alter the activity and selectivity of N2 reduction electrocatalysts.

[1] Skulason et al. Physical Chemistry Chemical Physics, 2012, 14, 1235.

[2] Montoya et al. ChemSusChem 2015, 8, 2180-2186.