bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Experience from Li-Ion Bess Delivering Primary Frequency Regulation in the Danish Energy Market
Authors: Swierczynski Maciej , Stroe Daniel Ioan , Teodorescu Remus , Laerke Rasmus , Kjaer Philip Carne 
Published: February 2020

Introduction

Li-ion batteries, after dominating the sector of portable electronics, are currently entering into a new market of the short and medium time stationary energy storage applications. Energy storage systems (ESSs) are considered to play a key role in the integration of the renewables in the grids of the high wind energy penetration and to participate in the future grids ancillary services. Nevertheless, they are currently missing market mechanisms and incentives for ESSs, which could attract potential investors and be economic viable.
This paper will present results and one year field experience gained from operation of the 1.6MW /0.4MWh Li-ion battery energy storage (BESS) demonstrator used for providing primary frequency regulation on the Danish market. Moreover, the results from the periodic check-ups of the Li-ion BESS performance degradation and ageing will be presented.

System description

The ESS, located in Western Denmark, is composed of two Li-ion battery containers connected in parallel, through the power converter system, to the MV bus of the transformer, as illustrated in Fig. 1. The first ESS (ESS1) is based on lithium iron phosphate (LiFePO4/C) battery cells (3.3V/2.3Ah) and it can deliver 0.4 MW/ 0.1MWh. The second ESS (ESS2) is based on lithium titanate oxide (LMO2/Li4Ti5O12) battery cells (2.3V/60Ah) and it can deliver 1.2 MW/ 0.3MWh.

Lifetime

Periodical reference performance tests of the both Li-ion BESSs were performed for a period of one year in order to determine and analyze the performance degradation, which is caused by delivering the PFR service. The reference performance tests consists of capacity test, hybrid pulse power characterization (HPPC test) and electrochemical impedance spectroscopy measurements performed on some battery modules removed from the BESS for a duration of the reference performance tests.

Economic analyses

High prices of the primary frequency regulation service, low BESS utilization factor and low depth of discharge cycles (Fig. 2) are making this service potentially economic viable on the Danish market. Thus, economic calculations will be provided including revenues, predicted lifetime of the BESSs and auxiliary power consumption (cooling systems of the BESS, cooling of the converter, etc).
Modeling and Lifetime Assessment of Lithium-Ion Batteries Used for Solar Firming Applications and Grid Storage
Authors: Lawder Matthew T , Northrop Paul W. C. , Subramanian Venkat R. 
Published: February 2020

The intermittent nature of many renewable power sources inhibits their implementation in the electric grid (1). Consumers demand an uninterrupted power supply and the unpredictable nature of renewables means that only a portion of the electric grid’s energy portfolio can come from these sources. However adding an energy storage device to renewable power sources can stabilize the source’s intermittency.
A coupled system can supply a constant level of power to the grid (below the system’s peak generation rating) by storing part of the energy created during peak generation hours and releasing that energy during periods of low or no power generation (see figure 1).
Our study utilizes a model of a photovoltaic solar cell coupled with a Lithium-ion battery. The system charges the battery anytime power generation exceeds the goal constant output and discharges the battery when the solar power output falls below the goal output. This protocol will control the system with the goal of generating the highest constant power output while still protecting the battery from degradation. Stabilizing the power source inevitably leads to sub-optimal charging and discharging patterns for the Li-ion battery and additionally can lead to intermittent cycling (small depth of discharge or small charging percentages). Our control strategy will seek to optimize both systems for single cycle and lifetime results.
The hybrid system will involve an electrochemical and transport based Li-ion battery model (2-5). Intermittent charging patterns obtained from solar insolation variations will be studied and their effects on capacity fade will be analyzed. The study will focus on the lifetime benefit that can be obtained from a battery during implementation into a solar firming application and seeks to understand the dynamics associated with coupled solar-battery system.

Acknowledgements

The authors acknowledge financial support from the U.S. Department of Energy’s Advanced Research Projects Agency- Energy (ARPA-E), and the Solar Energy Research Institute in India and the United States (SERIIUS), as well as, Washington University in St. Louis’ McDonnell Academy Global Energy and Environmental Partnership (MAGEEP)

References

1. Gopstein, A. M. Proceedings of the IEEE.,
100:2, 311 (2012).
2. Santhanagopalan, S., Guo, Q., Ramadass, P., and White, R. E. . J. of Power Sources., 156, 620 (2006).
3. Doyle, M., Fuller, T. F., and Newman, J. J. of the Electrochemical Society., 140, 1526 (1993).
4. Fuller, T. F., Doyle, M., and Newman, J. J. of the Electrochemical Society., 141,1 (1994).
5. Northrop, P. W. C., Ramadesigan, V., De, S., and Subramanian, V. R. J. of the Electrochemical Society., 158, A1461 (2011).
Hybrid Energy Storage System for Stationary Applications
Authors: Zhuk Andrey Zinovievich , Denshchikov Konstantin Konstantinovich , Fortov Vladimir Evgenievich , Sheindlin Alexander Efimovich 
Published: February 2020

Energy storage systems have a wide spectrum of functions. They must provide power quality, shaving of load change, matching in distributed power systems, bulk energy storage, and end-user reliability, e.g., uninterrupted power supply. Storage devices based on high-capacity batteries have a number of advantages: i) modular design and relatively compact size; ii) functional flexibility; iii) easy control and maintenance; iv) simple integration into Smart Grids. It is also well known that batteries have a number of unsolved problems, e.g.: i) high specific cost of stored energy; ii) insufficient cycle life (500 – 3 000 charge/discharge cycles); iii) significant decrease of cycle life at high charge/discharge current; iv) problem of depth discharge.
To solve the above mentioned problems, we propose the Hybrid Energy Storage system (HESS) incorporating supercapacitors in addition to batteries. Cost analysis of electrochemical storage systems based on batteries of different types, supercapacitors and their combination has also been carried out.
To verify the main principles of the proposal, we have designed and developed a HESS prototype. The main functional characteristics of the developed HESS were studied experimentally.
The prototype bases on Li-ion batteries and supercapacitors. Such energy storage system includes three main components: Li-ion batteries, supercapacitors, and grid interconnection consisting of two invertors and control and monitoring system. Energy storage capacity of developed HESS prototype is 100 kWh, nominal power—100 kW, peak power—200 kW. HESS was created and tested within the experimental facility including 1.5 MW gas turbine power plant, 200 kW controllable active and reactive loads, and a control and measurement system.
Experimental results showed that HESS successfully provides the following functions: (i) suppression of voltage, current, and frequency disturbances in the grid; (ii) compensation of reactive power in the circuit; (iii) uninterrupted power supply. In comparison with battery storage system without supercapacitors, HESS shows lower cost, and higher peak power. In hybrid energy storage system the presence of supercapacitors allows to shave peaks of power at the charge and discharge mode of the battery.
We believe that this feature of HESS will prolong the life time of batteries and thus increase the life time and reliability of the entire system.
A Radical Approach to Development of a Non-Aqueous Redox Flow Battery
Authors: Aaron Douglas , Delnick Frank , Sun Che-Nan , Nanda Jagjit , Zawodzinski Thomas A. 
Published: February 2020

The future of renewable energy, due to its inherent variability, will rest on the capacity of the electrical grid to reconcile power production and consumption. Electrical energy storage can take many forms, one of which is the redox flow battery (RFB), which boasts some unique advantages over other storage technologies. Non-aqueous RFBs, while far less developed than aqueous chemistries, may possess benefits over aqueous RFBs including higher voltage and greater energy density.
The electrochemistry of a series of anion radicals for possible use in flow batteries is reported. The solvent utilized in this work is tetra(ethyleneglycol) dimethylether (TEGDME) and was chosen due to its very large voltage window (~4 V vs. lithium) and capability of dissolving large concentrations of aromatic compounds. An appropriate triflate salt (sodium or lithium) was added to the TEGDME to improve conductivity, facilitating electrochemical measurements. After removing as much of the impurities as possible, TEGDME with triflate salt served as a stable electrolyte with nearly no observable electrochemical reactivity. Anion radicals were formed by simply adding sodium or lithium metal to various aromatics dissolved in TEGDME and triflate salt.
The aromatics considered in this work covered a range of complexity, from biphenyl and naphthalene up to large compounds such as coronene. Our initial screening found that the redox potentials of the aromatic-anion radical couples also spanned a large redox potential range. Some were highly reversible and some were quite unsuitable for a RFB due to irreversible redox behavior. Sodium- and lithium-generated anion radicals behaved similarly, with the sodium-generated radicals exhibiting generally more favorable redox behavior (larger current and better reversibility). In addition, many compounds also formed dianions, allowing for greater potential range and energy density for that material.
Ultimately, the goal is to develop a non-aqueous RFB. Initial tests to screen materials and improve cell design using the biphenyl-anion radical for the negative side are in progress. Capitalizing on the benefits of this non-aqueous RFB chemistry could result in lower overall system cost for electrical energy storage compared to other technologies.
Acknowledgement: We gratefully acknowledge the support of Dr. Imre Gyuk and the US DoE Office of Electricity for support of this work. CNS and JN acknowledge Laboratory Direct Research and Development (LDRD) seed funding for this work.
Superatmospheric MOCVD Growth of Bulk InGaN for Template and Optoelectronic Applications
Authors: Conway Matthew , Deguzman Panfilo C , Stokes E. B. 
Published: February 2020

InGaN, a III-Nitride wide bandgap semiconductor with theoretical bandgaps ranging between 0.7 eV (InN) and 3.39 (GaN), covers the entire visible spectrum and the near IR and UV. This makes InGaN an important material for photonic applications, including LEDs, laser diodes, and possibly solar cells.
To obtain smaller bandgaps within the material, more indium must be incorporated into the crystal. However, the differing chemical properties of indium and gallium, along with the limitations presented by the precursors, make indium incorporation beyond ~20% difficult to achieve, while maintaining high crystal quality. Work by Cheng Li et.al. indicates that photoluminescent intensity improves at higher pressure growths (still subatmospheric). Basic thermodynamics indicate that the temperature can be increased during growth at increased growth pressures, allowing an increase in process space. Also, that material stability can be improved by increasing the pressure during growth of InGaN.
A superatmospheric metal-organic chemical vapor deposition (MOCVD) reactor was designed and fabricated at UNC Charlotte to investigate the superatmospheric growth of InGaN, especially for growing high indium content InGaN. This reactor was designed to minimize gas phase reactions and to sustain smooth precursor flow while under superatmospheric conditions, solving one of the main problems with superatmospheric growth.
Experiments were done to obtain recipes for initial growths. This included finding critical thicknesses for InGaN of a set composition on GaN templates, V:III ratio experiments, estimating nitrogen vacancies by comparing elemental percentages from the EDAX results, optimizing growth temperatures, and flows for epitaxial growth.
Bulk InGaN was grown on Al2O3 and on n-type GaN templates. Early growths of InGaN on Al2O3 showed absorption below the GaN bandgap, with absorption starting around 2.4eV (~516nm) [figure]. Indium deposition was confirmed through EDAX results. X-ray diffraction results will be included in full paper, indicating phase and composition results. Early results grown on Al2O3did not show high intensity room temperature photoluminescence, although it could be detected with a spectrometer. However, the early photoluminescence results corresponded with absorption results, indicating that they were accurate.
InGaN was also grown on n-type GaN substrates, which were also grown by MOCVD and donated by VEECO. Greater photoluminescence was measured from early growths on GaN templates with the same recipes, presumably because the crystalline quality was increased by growing on a smooth, relaxed substrate, with a closer lattice match. Growth conditions, rates, and results will be discussed, along with any conclusions about the effects and capabilities of superatmospheric growth on parameters of bulk InGaN.
(Invited) Photon Management Using Si Nanocrystals and Er3+ Ions: Generation of Hot Carries upon Absorption of Low-Energy Photons
Authors: de Jong Elinore M.L.D. , Saeed Saba , Gregorkiewicz Tom 
Published: February 2020

The most important limitation for efficiency of photovoltaic energy conversion appears due to the enormous mismatch between the broad-band character of the solar radiation and the discrete operation mode of solar devices, as determined by the specific bandgap energy of the active medium. One remedy for that would be the spectral transformation of the solar radiation before it enters a photovoltaic device. Specifically, such a “solar shaper” should split the large energy photons into smaller ones, whose conversion efficiency is optimal.
In my presentation, I will discuss how shaping of the solar spectrum can be achieved using layers of Si nanocrystals with and without Er doping. In such systems efficient photon transformation can be realized by quantum cutting [1] and/or emission from Er3+ ions sensitized by Si nanocrystals [2]. Also the recently identified [3] ultra-efficient colloidal Si nanocrystals can be used for the purpose. I will present evaluation of external quantum efficiency of emission from thin layers of Si nanocrystals in SiO2 and its evolution upon introduction of Er3+ ions. Using differently prepared materials I will evaluate how this can be maximized. I will also discuss energy efficiency of solar shapers based on Si nanocrystals and Er3+ ions.
[1] M.T. Trinh et al., Nature Photonics 6, 316-321 (2012).
[2] S. Saeed et al., under consideration
[3] K. Dohnalova et al., Light: Science and Applications 2, e47 (2013)
Simulation of the Ammonia Electrolysis Process
Authors: Diaz Luis A. , Estejab Ali , Botte Gerardine G. 
Published: February 2020

Introduction

The electrochemical oxidation of ammonia, in alkaline media, has been proposed as an efficient alternative for the deammonification or wastewater. Furthermore, the ammonia electrolysis process has the potential to co-generate fuel grade hydrogen with just five percent of the energy required from water electrolysis, which makes this process attractive for its self-sustainable integration in wastewater treatment plants [1]. Motivated by the advantages of the ammonia electrolysis, Botte and members of the research team at the Center for Electrochemical Engineering Research (CEER) have performed extensive research in the ammonia electro-oxidation reaction. Through the analysis of well defined hydrodynamic electrochemical cells, coupled with mathematical modeling and parameters estimation, it was possible to establish a reaction mechanism and define the kinetic parameters that represent the intrinsic reaction kinetics of the ammonia electro-oxidation [2].
In this work, a simulation platform for an ammonia electrolysis flow cell is proposed to be implemented in ASPEN plus in order to achieve sensitivity and cost analysis along with process optimization. User defined platforms were developed using experimentally validated mathematical models of a parallel cell electrolyzer, which include the hydrodynamic behavior of the flow cell electrolyzer evaluated through experimental residence time distribution analysis.

References

[1] L.A. Diaz, G.G. Botte, Ind. Eng. Chem. Res. 51 (2012) 12167.
[2] L.A. Diaz, G.G. Botte, J. Catal. (Submitted for publication 2014).
Spin-Lattice Coupling Studies of Electrode Material for 2nd Battery
Authors: Lee Seongsu , Kim Hyungsub , Kang Kisuk 
Published: February 2020

Crystal and Magnetic structure of second battery electrode materials using neutron power diffraction is essential because of its sensitivity to observe the light element atom such as Li, Na and O. It is very important to define a position and occupation of conduction ion(Li-ion) for recognizing their reaction mechanisms. To do further advanced research combined Rietveld refinement and MEM (Maximum Entropy Method) is revealed the useful information for understanding the conduction mechanism.
By detailed structural analysis of electrode materials for rechargeable battery with neutron powder diffraction, we should understand an iso-structural change such as an oxygen ion tilting, a change of bond distance and an occupation variation etc. for studying the conduction mechanism. An iso-structural change in electrode is appeared by the charging/discharging, size-control, doping and spin ordering process. The control of iso-structure change as functions of several external conditions is very substantial to realize next generation 2nd battery with high-capacity, high-efficiency and good-safety. In this study, we have investigated the magnetic and crystal structure of electrode NaxFe3(PO4)2(P2O7) using neutron powder diffraction. We have observed that the spin ordering of Fe induces the iso-structure change of NaxFe3(PO4)2(P2O7). Even though the spin ordering of this material is happened at a very low temperature, the imagination about correlation between crystal and magnetic structure in electrode should be proposed us the clue to realize the new concept’ 2nd battery which the conduction property of electrode can be controlled by the spin ordering of magnetic ion.
Enhanced Properties of Sulfur-Infiltrated Carbon Sphere with Conductive Polymer Coating for Lithium-Sulfur Batteries
Authors: Kim Do Kyung , Moon San , Jung Young Hwa , Kim Joo-Hyung 
Published: February 2020

Lithium-sulfur (Li-S) battery is promising energy system with a high theoretical energy density (2500 Wh kg-1), which is ~7 times larger than those of the current LIBs (~387 Wh kg-1) utilizing the unparalleled theoretical capacity of sulfur (1675 mAh g-1). Sulfur as a cathode material also has other advantages such as non-toxicity, low cost, and abundance of raw materials.For all its virtues, several challenges such as an insulating nature of sulfur (conductivity ~10-30), a large volume expansion by up to 80 % upon full lithiation and a severe capacity fading during cycling still remained unsolved. Sulfur, unlike the insertion based electrode, suffers a serious of structural and morphological changes during cycling with the formation of high-order lithium polysulfides (Li2Sn, 2<n≤8) and low-order lithium polysulfides (Li2S2 and Li2S), which are insulators. Besides, the high-order lithium polysulfides are soluble in current liquid electrolyte at the early stage of discharging. The dissolution of high-order polysulfides results in the so-called shuttling effects.Those problems should be addressed for utilization of lithium-sulfur battery in consumer electronics.
In this present investigation, we developed sulfur infiltrated hollow carbon sphere with conductive polymer layer. The numerous small pores in carbon sphere were formed by evaporation of inner materials without damages of outer carbon layer. The conductive polymer layer (PEDOT) coated on the surface of carbon sphere could improve in the trapping of polysulfides and play a role in buffer layers against the volume changes of sulfur. The electrode design could improve the electrical performance with resolving the aforementioned issues.
Invited: Na-Ion Battery Technologies: Present Status and Update
Authors: Johnson Christopher S. 
Published: February 2020

Na-ion batteries (sodium-ion batteries or SIB) that operate at ambient temperature present a great opportunity for the development of new energy storage systems that could be ideal for a myriad of applications. Low cost, long-term stability and great abundance of Na are the major drivers that can move this technology forward. Na batteries also could be positioned as a backup technology to Li-ion batteries, which would be of great value and insurance to the battery industry as one should not rely solely on one type of battery technology. Energy densities of SIB can vary greatly depending on the voltage and capacity of the active materials. While typically the energy densities of Na batteries are marginally lower compared to Li-ion batteries (about 30-50%), a host of new chemistry of compounds that are low cost with good performance are possible. For example, a cathode material that consists solely of Na Fe, and Mn would be low cost and highly safe. These elements are quite abundant and easily processed into active materials for the cathode using our new synthetic methods. In addition low-cost carbon materials such as those that are derived from pyrolysis of plant matter can serve as a reversible low-cost anode host for Na cations which are stored within graphene regions and nano-cavity or nanopores.
In this talk, I will discuss the desirable characteristics of SIB technology by providing examples on electrochemical and battery cycling performance results from new materials utilized as electrodes in SIBs.

Acknowledgement. This work was supported by the U.S. Department of Energy, U.S. DOE-BES, under ContractNo.DE-AC02-06CH11357.