bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrolyte Effects on the Electrochemical Behavior of Electrolytic Manganese Dioxide in Alkaline Aqueous Media
Authors: Rus Eric D. , Moon Geon Dae , Hertzberg Benjamin Joseph , Abeykoon Milinda , Bai Jianming , Steingart Daniel A , Erdonmez Can K.
Published: February 2020

Electrolytic manganese dioxide (EMD) is the cathode material typically used in primary alkaline cells, owing to its low cost and relatively high gravimetric capacity.   These qualities also make it attractive as a cathode for secondary cells, though unfortunately its cycle-life is relatively short. The cycle-life can be improved under certain conditions, e.g. at limited depth of discharge [1]; there also reports of improved cycleability in LiOH solutions or against non-zinc electrodes [2].  We have investigated the effects of electrolyte composition on the electrochemical properties of EMD with cyclic voltammetry and galvanostatic cycling.  More particularly, we focused on LiOH and KOH electrolytes, with ZnO present or absent.  The structural evolution of the material during electrochemical cycling was studied using in situ synchrotron x-ray diffraction.  While the structure of the EMD appears to remain largely intact after a single cycle in KOH solution, it undergoes an irreversible transformation at low depths of discharge when reduced in lithium hydroxide solutions.  Both electrochemical and diffraction measurements indicate this transformation was complete within the first reduction, though the material undergoes further structural evolution with extended cycling.  The electrochemical behavior of ramsdellite MnO2, the prototypical structure for EMD, was also examined in a LiOH electrolyte as a point of comparison.  Ramsdellite underwent an irreversible transformation at low depths of discharge in a manner similar to that observed for EMD.  The evolution of the diffraction pattern of the ramsdellite upon electrochemical reduction was very similar to that reported for chemically reduced ramsdellite in organic media [3].  In situ measurements with zincate-containing electrolyte showed ZnMn2O4 (hetaerolyte) to form sooner in LiOH solutions than KOH solutions.  Curiously, hetaerolyte underwent some structural changes upon re-oxidation and we will provide some possible interpretations of this observation.  Short-term (<30 cycles) capacity and cycleability trends observed as a function of the various electrolyte compositions and potential limits will also be presented.

[1] K. Kordesch, J. Gsellmann, M. Peri, K. Tomantschger, R. Chemelli Electrochim. Acta 1981, 26, 1495-1504.

[2] M. Minakshi Electrochem. Solid-State Lett. 2010, 13, A125-A127.

[3] M.M. Thackeray, M.H. Rossouw, R.J. Gummow, D.C. Liles, K. Pearce, A. De Kock, W.I.F. David, S. Hull Electrochim. Acta 1993, 38, 1259-1267.
Modeling of the Thermal Behaviors of an Ultracapacitor Module
Authors: Park Sung June , Yi Jaeshin , Shin Chee Burm , Min Kyung-Seok , Choi Jongrak , Lee Ha-Young
Published: February 2020

Ultracapacitors, also known as supercapacitors, have the potential to meet the increasing power requirements of energy-storage systems for automotive applications. As compared to batteries, ultracapacitors offer a higher power density, higher efficiency, and longer shelf and cycle life. Because the performance of an ultracapacitor depends on temperature, it is important to calculate accurately the thermal behavior of a single ultracapacitor cell and the module composed of multiple ultracapacitor cells for the efficient and reliable systems integration of an ultracapacitor in automotive applications.

In this work, modeling is performed to study the thermal behavior of an ultracapacitor module. The ultracapacitor module is subject to the charge/discharge cycling with constant-current between 1.35V and 2.7V. The validation of the modeling approach is provided through the comparison of the modeling results with the experimental measurements.

Fig. 1 shows the schematic diagram of the ultracapacitor module composed of the 18 ultracapacitor cells (3.7V/3000F) from LS Mtron Ltd. In Fig. 2, the variation of surface temperature with time from the experiment is compared with that from modeling during the charge-discharge cycles with the constant current of 200 A.

Figure 1
Synthesis and Evaluation of Fluorinated Carbonates As Solvents for High-Voltage Lithium-Ion Battery Electrolyte
Authors: Hu Libo , Xue Zheng , He Meinan , Su Chi-Cheung , Zhang Zhengcheng
Published: February 2020

High-voltage Li-ion battery draws great interest due to the promise to deliver high power and energy which are essential to transportation applications. The bottleneck to this technology is the anodic stability of the organic electrolyte. Approaches to solve this problem include developing additives to kinetically stabilize the cathode/electrolyte interface  and developing novel electrolyte systems that are intrinsically stable toward oxidation at high potential . Our group has been taking the second approach with a focus on fluorinated compounds as electrolyte solvents.  

We have synthesized a series of fluorinated cyclic carbonates and linear carbonates and evaluated their electrochemical stability and other physical characteristics. Electrolytes formulated from these fluorinated compounds have demonstrated excellent anodic stability and some of the formulations also showed enhanced cell performance for LiNi0.5Mn1.5O4(LNMO)/ graphite full cells. Characterization of harvested electrolyte with NMR and GC-MS revealed that less soluble decomposition products were generated in the fluorinated electrolyte compared with the conventional electrolyte. Investigation of the cycled electrodes with SEM and TEM revealed that the high stability of the fluorinated electrolyte on the cathode not only helped with the electrolyte decomposition problem, but also reduced the degradation of the electrode material as well.
Origami-Type Supercapacitor Chips with High Voltage Performance
Authors: Nam Inho , Kim Gil-Pyo , Park Soomin , Bae Seongjun , Yoo Young Geun , Park Jongseok , Han Jeong Woo , Yi Jongheop
Published: February 2020

The recent boom in electronics requires high performance and stretchable energy storage systems. As a result, the growth of energy storage system with patterning assembly technologies has been accelerated. In this research, we introduce a novel design in the supercapacitors, which enables us to realize the unlimitedly increased potential window characteristics that are unavailable when conventional schemes are applied. The patterning assembly of superapacitors improves the electrochemical performance of the energy storage by a high surface-to-volume ratio and non-use of binders and separators in their fabrication. Moreover, the technique generates physical advantages, such as folding and stretching of the supercapacitor system. The new supercapacitor system is composed of periodically isolated electrodes and sectionalized electrolytes without restrictions on electrode or electrolyte selections. The isolated electrodes and sectionalized electrolytes are key factors for the extremely packed analogical series circuit system which permits energy and power to be simultaneously increased. This energy storage system also assumes an origami-type that accommodates extremely high stable stretching. We believe that our concept provides noteworthy implications across a number of disciplines toward ultimate energy, power and stretchable devices for next generation of electronics.
Synthesis of Cobalt Oxide Nanostructures on Carbon Paper Using Intense Pulsed Light (IPL) and Supercapacitor Electrode Applications
Authors: Lee Sanghyun , Jang Kihun , Yu Seongil , Kim Hak-Sung , Ahn Heejoon
Published: February 2020

Transition metal oxides have received tremendous interests in supercapacitor materials over the last decade because they can provide higher energy density than conventional carbon materials and better electrochemical stability than polymer materials. They not only store energy like electrostatic carbon materials but also exhibit electrochemical faradaic reactions between electrode materials and ions within appropriate potential windows. Several methods have been used to synthesize metal oxide nanostructures including chemical bath deposition, hydroxide decomposition, thermal decomposition of carbonates, nanocasting, electrodeposition, combustion, coprecipitation, and the sol-gel method. Many of these have drawbacks in that they are energy consuming, lengthy and involve multiple steps. Especially, all methods require calcinations/heat treatment at 200-600oC for 1-24hrs. Therefore, faster, more facile and energy efficient methods for metal oxide nanostructure production are of interest. Here we report an agile and facile method for the preparation of high-performance supercapacitive cobalt oxide nanoflakes by using an intense pulsed light (IPL) technology. By this method, the cobalt oxide formation can be accomplished within milliseconds by irradiating the broad wavelength light with high energy density on cobalt oxide precursor, which is exceptionally faster than other metal oxide formation methods. We have fabricated cobalt oxide nanoflakes on flexible carbon-paper substrate by using the IPL technique. The as-prepared substrates are further utilized as a supercapacitor electrode, and their supercapacitive performance will be discussed in the presentation.
Experimental Investigation of Carbon Deposition on a Ni/YSZ Anode of Solid Oxide Fuel Cell
Authors: Hua Dong , Zhang Xiongwen , Li Guojun , Yang Naixing , Fan Pengfei
Published: February 2020

Solid Oxide Fuel Cell (SOFC) is a promising energy conversion device with high efficiency and low emissions. Nickel-doped yttria-stabilized zirconia (Ni-YSZ) is the most commonly used material for anode of SOFC. However, a major concern with Ni-based anode is carbon deposition when SOFC is operated by hydrocarbon fuels. The deposited carbons on the surface of catalysts affect the activity of catalysts and the flow of gas through the anode. The carbon formation has to be effectively controlled in the operation of SOFC before the hydrocarbon fuels, such as natural gas, biogas, etc., are widely used in SOFC [1-2].

Methane cracking and CO disproportionation (Boudouard reaction) are the main reactions causing carbon deposition. The methane cracking reaction has been intensely studied by researchers in both kinetic models of simulations and experiments [3-5].There has also been efforts to observe the CO disproportionation reaction at temperatures from 773 to 848K [6]. Mostly, these work are applied to the operating temperatures below 600℃, which are not applicable to the operating conditions of SOFC.

In this work, experiments are carried out to study the carbon deposition from the methane cracking and CO disproportionation reaction over a Ni/YSZ catalyst. The carbon deposition experiments for the anode samples exposed to CH4+H2 and CO+CO2gas mixtures with different gas compositions are conducted separately. The steady-state rates for carbon deposition by methane cracking and CO disproportionation are measured at different temperatures between 873K and 1073K, which is the typical operating temperatures of SOFC. Based on the experimental data, the kinetic models for both methane cracking and CO diaproportionation are established for the operating environments of SOFC. Microstructures of the carbon deposits in the anode samples are examined by a Hitachi 7800F field emission scanning electron microscope (FE-SEM) and an energy dispersive X-ray spectrometer (EDS).

Acknowledgements:

This work is financially supported by Projects from National Nature Science Foundation of China No. 51276145.

Reference:

[1].   X. Zhang, G. Li, J. Li and Z. Feng, Energy Conversion and Management, 48, 977 (2007).

[2].   T. Chen, W. G. Wang, H. Miao, T. Li and C. Xu, Journal of Power Sources, 196, 2461 (2011).

[3].   I. Alstrup and M. T. Tavares, Journal of Catalysis, 139, 513 (1993).

[4].   F. Valdés-Parada, H. Romero-Paredes and G. Espinosa-Paredes, international journal of hydrogen energy, 36, 3354 (2011).

[5].   J.-W. Snoeck, G. Froment and M. Fowles, Journal of Catalysis, 169, 250 (1997).

[6].   J.-W. Snoeck, G. Froment and M. Fowles, Industrial & engineering chemistry research, 41, 4252 (2002).
Optimization of Support Materials for Intermediate Temperature Molten Carbonate Fuel Cells (IT-MCFC)
Authors: Li Na , Poozhikunnath Abhinav , Aindow Mark , Maric Radenka
Published: February 2020

Molten carbonate fuel cells (MCFCs) normally operate at between 600 and 700 °C, but intermediate temperature (ca. 500 °C) MCFCs could be achieved by a combination of improved materials design, properties, and processing. A lower operating temperature would reduce heat loss, thermal stress and corrosion problems, and would also improve mechanical robustness. Thus the implementation of alternative materials and structures could yield significant cost savings.

Two types of MCFC design were considered in this study: cathode-supported and metal-supported. The support substrates were selected on the basis that they should exhibit sufficient mechanical strength to withstand a ΔT of 80 °C for a 100 cm2 cell at the operating temperature without imparting significant performance loss through electrical resistance increase or electrode deactivation.

In this study, lithiated nickel oxide (LiNiO) has been selected as the main candidate for cathode support; this material is closely related to state-of-the-art cathode compositions used in high temperature MCFCs. The candidate metal support materials are mostly austenitic ferritic stainless steels such as SS 310S, SS316L, SS446 etc [1], which are used as the state of art bipolar plate materials to withstand the molten salt corrosion during fuel cell operation [2]. A critical evaluation has been performed of these candidate cell support materials, and potential substrate coating materials and techniques have also been considered [3]. The mechanical strength, electronic conductivity and material compatibility have been evaluated to optimize the support materials. 

References:

[1] Frangini, S. et al. J. Power Sources, 2008,182, 462-468.

[2] Frangini, S. et al. Recent Patents on Corrosion Science, 2011, 1, 93-107

[3] Dicks, A. et al. Current Opinion in Solid State and Materials Science, 2004, 8, 379–383
Graphene-Coated Carbon Nanotube Aerogels Decorated with MnO2 for Ultracompressible and Highly Stable Pseudocapacitors
Authors: Wilson Evan , Islam Mohammad F.
Published: February 2020

Electrochemical capacitors (ECs), including supercapacitors and pseudocapacitors, are desirable energy sources for a wide variety of applications. ECs display high power due to their rapid electrochemical kinetics, though pseudocapacitors typically achieve higher energy than supercapacitors due to the presence of faradaic reactions during operation. However, the poor observed lifetime for pseudocapacitors precludes their use in many applications. This poor lifetime comes about due to structural degradation caused by repeated stress on the crystal structure during charging and discharging the electrodes. One route towards suppressing the degradation is by constructing an electrode structure that can tolerate these stresses and alleviate the strain on the pseudocapacitive material.

We have previously developed highly strain-tolerant aerogels by coating a conductive and high surface area single-walled carbon nanotube network1 with one or more layers of graphene, rendering them ultracompressible and resistant to fatigue.2 By decorating these aerogels with a thin layer of MnO2, we have developed a pseudocapacitor electrode that can undergo large reversible strains without capacitance degradation, ultimately affording high stability and lifetime for the cells.

In this talk, I will present fabrication and structural characterization of graphene-coated carbon nanotube networks decorated with MnO2, in addition to their electrochemical performance. The electrodes possessed high capacitance in an uncompressed state and when compressed to large strains. Further, the capacitance was recovered fully upon release of the cells because of the robustness of the electrode material. These pseudocapacitors were highly stable, with the capacitive performance and lifetimes being largely unaffected even after ~10,000 compression-release cycles. This work was funded by the National Science Foundation through grants CBET-1335417 and DGE-0966227.

References

1. K. H. Kim, Y. Oh and M. F. Islam, Advanced Functional Materials, 23, 377–383 (2012).

2. K. H. Kim, Y. Oh and M. F. Islam, Nature Nanotechnology, 7, 562–566 (2012).
Characteristics of Mn-Co-Ni Oxide Powders Prepared By Chemical Reduction Method for a Supercapacitor Electrode
Authors: Chun Woo Won , Shin Myung Sik , Choi Bit Na , Chung Chan-Hwa
Published: February 2020

Supercapacitor is considered as a candidate for the promising energy storage device due to its permanent properties, high power density, and short charging time [1]. It can be used as a backup system, starting power of fuel cell , hybrid vehicle, or large industrial equipment [2].

 There are two typical types of supercapacitors. One is electrochemical double layer capacitors (EDLC) utilizing a polarization phenomenon occurring between the surface of electrode and electrolyte. And the other is pseudo-capacitors using high-speed redox reactions. Normally, transition metal oxide and conductive polymer are used as the electrode materials of pseudo-capacitors [3]. Ruthenium [4] and nickel [5] are often studied among various metal electrode. They exhibit excellent performance, but it is difficult to commercially used because of its high price and eco-unfriendly with strong acid or alkali electrolyte. Therefore, manganese has been studied as an alternative materials.

 Manganese is showing potential to be used as a supercapacitor electrode because of its low price and eco-friendly property. But, the mechanical strength of manganese is weak, so discharge cycle life is relatively short as compared with that of other electrode materials [6]. In addition, manganese oxide is limited used in conditions that require high power because the power density is reduced with increasing contact resistance [7].

 In this study, we fabricate alloy of cobalt, nickel, and manganese prepared by chemical reduction method using the reducing agent (N2H4) and the dispersant (C6H5Na3O7) [8]. The unique shape of Mn-Co-Ni oxide powder was formed by combing powder of Mn (plate like), Co (flower like), and Ni (sphere) (Figure. 1). The electrochemical performance of the Mn-Co-Ni oxide was measured with cyclic voltammetry and charge-discharge test.

Reference

[1] J.R. Miller, P. Simon, Science, 321 (2008) 651-652.

[2] S. Sarangapani, B.V. Tilak, C.P. Chen, J. Electrochem. Soc., 143 (1996) 3791-3799.

[3] K. Zhang, L.L. Zhang, X.S. Zhao, J. Wu, Chem. Mat., 22 (2010) 1392-1401.

[4] J.P. Zheng, P.J. Cygan, T.R. Jow, J. Electrochem. Soc., 142 (1995) 2699-2703.

[5] V. Srinivasan, J.W. Weidner, J. Electrochem. Soc., 144 (1997) L210-L213.

[6] S.C. Pang, M.A. Anderson, T.W. Chapman, J. Electrochem. Soc., 147 (2000) 444-450.

[7] Q. Li, Z.-L. Wang, G.-R. Li, R. Guo, L.-X. Ding, Y.-X. Tong, Nano Lett., 12 (2012) 3803-3807.

[8] K.H. Kim, Y.B. Lee, S.G. Lee, H.C. Park, S.S. Park, Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process., 381 (2004) 337-342.

Figure 1
Electrochemically Synthesized CDC for Supercapacitors and Performance Ionic Liquid Electrolytes
Authors: Camargo Luis G.B. , Palazzo Benjamin G. , Taylor Gregory , Norris Zach , Patel Yash , Hettinger Jeffrey , Yu Lei
Published: February 2020

Carbide-Derived carbon (CDC) is a new type of porous carbon material with high purity, narrow distribution of pore sizes, and significant specific surface area. Due to these unique properties, CDC was found to be very useful for gas storage, flow sensors, and as electrode material for electrochemical energy storage devices such as supercapacitors. Currently, the most reliable method to synthesize CDC is to remove the metal or metalloid elements selectively from binary or ternary carbide precursors. This is achieved by chlorine gas treatment (chlorination) at a temperature of 200 oC or higher. At elevated temperatures, metal / metalloid elements can be oxidized to be volatile metal chlorides and purged off by Ar gas steam. Thus, the left-over carbon is metal free and sp2 or sp3 hybridized. So far, this method of etching has been very dominant but one downside is that the Cl2 gas is very toxic and the process itself is relatively expensive. On the other hand, alternative oxidation methods to prepare CDC at milder conditions have been rarely explored. In this work, conversions using electrochemical methods are reported that oxidize vanadium carbides (VC and V2C) in aqueous solutions at room temperature to prepare CDC thin film as electrode materials of supercapacitors. It was found that VC and V2C can both be oxidized at a potential of about 0.5 V vs. Ag/AgCl or higher in neutral, acidic, or basic solutions. X-ray diffraction results indicate that about 33% of the vanadium on the surface layer of the V2C film was removed and the vanadium is readily observed in the electrolyte solutions by ICP-MS. The so-produced CDC thin film electrode (ca. 2.0 - 2.6 μ thick) has a porous morphology and bears specific double layer capacitance values as high as 0.026 F/cm2 (or 130 F/cm3) with some dependence on the oxidation potential, time, and electrolyte solutions. The so-produced CDC thin films showed high double layer capacitance as well when ionic liquid electrolytes are used. The performance depends on the structures of the cations and the anions of ionic liquids.
On the Defect Chemistry, Electrical Properties and Electrochemical Performances As Solid Oxide Fuel Cell Cathode Materials of New La-(Sr/Vac)-Co-Ti-O Perovskites
Authors: García-Alvarado Flaviano , Gómez-Pérez Alejandro , Pérez-Flores Juan Carlos , Azcondo-Sánchez M.Teresa , Yuste Mercedes , Bonanos Nikolaos , Amador Ulises , Canales-Vázquez Jesús
Published: February 2020

Perovskite-type oxides are well known materials that have been proposed as electrodes and electrolytes for solid oxide fuel cells (SOFCs). The structure, which is referred to the ABO3 stoichiometry, can accommodate many different transition metal ions in the B-site; its electronic conductivity will vary depending upon the nature and the oxidation state of these ions. On the other hand, the creation of anion vacancies or aliovalent substitution in the A position will affect to oxide ion conductivity. A proper combination of B cations and doping or vacancy creation in A-site may provide new materials with valuable properties for SOFCs.

We have analysed the effect of La3+ by Sr2+ substitution and vacancies creation in several double perovskites, La2MTiO6 (M = Co, Ni, Cu). Defect chemistry and electrical behavior have been investigated in order to unveil the nature of charge carriers. Electrochemical performances have been assessed through polarization resistance measurements. In this communication we present the results regarding La2SrTiO6 perovskites.  La/Sr substitution in La2-xSrxCoTiO6-δ produces Co2+ to Co3+ oxidation while vacancies in La2-xCoTiO6-δ yield Co2+ oxidation for low A-vacancy concentration. Interestingly, oxygen vacancies are predominant for higher A-vacancies concentration. These oxygen vacancies seem to be associated to La vacancies likely inhibiting oxide ion mobility. Accordingly to operating defect chemistry the electrical behavior of the La2-xSrxCoTiO6 system in a wide pO2 range is dominated by p-type electronic conduction mechanism while for La2-xCoTiO6-δ the p-type behavior is only observed at high pO2 and changes to n-type at low pO2. The contribution of oxide ion conductivity could not be unveiled due to the larger contribution of electronic component to total conductivity in the pO2 range analyzed. The preliminary evaluation of the electrodes performance reveals polarization resistances in the 0.6-0.9 Ωcm2 range at 1073 K in oxygen for La2-xSrxCoTiO6-δ, which is fairly similar to the values obtained for LSM-based cathodes. However much higher polarization resistances are found for the La2-xCoTiO6-δ  with values between 2.6-9.6 Ωcm2 in air at 1073 K.  Additional electrochemical experiments to determine performances of planar (1-2 cm2) single SOFC bearing La2-xSrxCoTiO6-δ as the cathode are now in progress.
Functionalized Carbon Based Electrodes for High-Performance Energy Storage Devices
Authors: Liu Tianyuan , Kavian Reza , Lee Seung Woo
Published: February 2020

Rechargeable Li-ion batteries have become the main power sources for portable electronic devices by utilizing transition metal oxides or metal phosphates as the positive electrode materials. However, large-scale energy storage applications, such as electric vehicle, smart grid, and renewable energy storage, stimulate the need for the development of more sustainable and affordable organic based electrode materials. Recent research showed that oxygen functional groups on the surface of carbon materials, such as carbon nanotube and graphene oxide, can react with Li ions at ~3 V vs Li. In addition, these surface redox reactions have been utilized to develop carbon based positive electrodes for the Li rechargeable batteries or Li-hybrid capacitors.

To further advance the surface redox reactions of carbon materials, we have assembled highly porous nanostructured electrodes employing the functionalized carbons based on simple and versatile processing techniques. There are two key advantages in the assembled electrodes: the porous carbon support can support fast electron conduction and ionic diffusion, while redox-active functional groups on the carbon support can store a large number of Li or Na ions. Consequently, the functionalized carbon electrodes deliver high gravimetric capacities over ~150 mAh/g with high redox potentials over ~3 V vs. Li, proposing promising positive electrodes for rechargeable batteries or hybrid capacitors. In addition, these functionalized carbon electrodes can sustain capacities over 1,000 cycles without significant capacity decay. Moreover, we incorporated external redox-active materials, such as organic molecules and polymers, into the porous carbon electrodes to further increase energy density of the electrodes.
Difference in the Intercalation of Sodium Ions and Lithium Ions into Hard Carbon Electrodes
Authors: Li Xiaolin , Zhan Hui , Engelhard Mark H , Schemer-Kohrn Alan L. , Shao Yuyan , Chen Xilin , Pan Huilin , Liu Jun , Sprenkle Vincent
Published: February 2020

Introduction

 

Na is in the same element group with Li and its diameter is only ~40% larger than a Li ion.1-2 Therefore, it is believed that it has very similar intercalation chemistry in Na-ion batteries as Li in Li-ion batteries. Hard carbon is a promising anode material for both Li-ion and Na-ion intercalation and has almost similar specific discharge capacity.3 Yet, it has been reported that the Na ions and Li ions are quite different when intercalating into hard carbon and the solid state interphase (SEI) on hard carbon anodes has different composition/morphology for Na and Li ions.4-5In this work, we further elucidate how the solid electrolyte interlayer can induce significant difference in the intercalation of Na-ion and Li-ion into hard carbon and hence lead to significant difference in the discharge capacity. Electrolyte additive effect was also investigated.

Results and Discussion

 

The same hard carbon electrode was cycled subsequently v.s. Li metal in Li-ion electrolyte and v.s. Na metal in Na-ion electrolyte. The capacity remains similar of ~200 mAh/g when it was switched back to Li-ion batteries. Yet, when the hard carbon electrode was cycled subsequently v.s. Na metal in Na-ion electrolyte and v.s. Li metal in Li-ion electrolyte, the capacity shows significant drop from ~200 mAh/g to ~40 mAh/g when it was switched back to Na-ion batteries. The electrolyte for Li-ion battery and Na-ion battery is only different for the alkali metal ion.

 Fig. 1.  Hard carbon electrodes cycled subsequently v.s. Li or Na metal in Li-ion or Na-ion electrolyte.

 

 

Acknowledgement

The authors would like to acknowledge financial support from the U.S. Department of Energy’s (DOE’s) Office of Electricity Delivery & Energy Reliability (OE) (under Contract No. 57558). (A portion of) The research was performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

 

References

MD Slater, DH Kim, EJ Lee, and CS Johnson. Adv. Funct. Mater. 23(2013):947.

HL Pan, Y-S Hu, and LQ Chen. Energy Environ. Sci. 6 (2013): 2338.

D.A. Stevens, J. R. Dahn. J. Electrochem. Soc. 147 (2000), 1271-1273.

S. Komaba, W. Murata, T. Ishikawa, N. Yabuuchi, T. Ozeki, T. Nakayama, A. Ogata, K. Gotoh, K. Fujiwara. Adv. Funct. Mater. 21 (2011), 3859-3867.

S. Komaba, T. Ishikawa, N. Yabuuchi, W. Murata, A. Ito, Y. Ohsawa. ACS Appl. Mater. Interfaces 3 (2011), 4165-4168.

Figure 1
Sulphate Doped Polypyrrole Encapsulated Tin Composite for the Lithium Ion Battery Anode
Authors: Gopukumar Sukumaran , Ravikumar Raman
Published: February 2020

Tin is considered as a promising candidate for the lithium ion anode which is synthesized by co-precipitation technique using stabilizing agents such as C-TAB. The conducting Sn-sulphate doped polypyrrole is synthesized by polymerization of pyrrole monomers in the nano tin particles dispersed in 0.1% PVP + water medium using ammonium per sulphates as a polymerizing as well as doping agent.  The XRD, SEM and TEM analysis confirms the formation of polypyrrole coated on tin nano particles to form a composite. Pulverization effect of tin metal electrode is the highly significant challenge to solve while charge-discharge process, thus while lithium insertion and desertion process the polymer based conductive material like polypyrrole  (conductive polymer) coated on tin nano particle holds the active material to avoid isolation from the conductive matrix, which act as a current collector. The coating thickness is being optimized by the various weight ratios of polymer to tin nano particles from 5 to 20%. The thickness of the coating is analyzed by SEM and TEM; the electrochemical behavior is investigated by EIS and charge-discharge studies. 80:20 ratio of tin-polypyrrole composite gives almost 100% capacity retention at the rate 400 mA g-1 and delivers initial specific discharge capacity of 878 mAh g-1

Figure 1
Comparison of Pyrochlore and Perovskite Electrodes Towards the Oxygen Evolution in Alkaline Media
Authors: Abreu Sepulveda Maria Angelica , Trinh Phong , Malkhandi Souradip , Quesnel David J , Narayanan S. R. , Manivannan A.
Published: February 2020

The identification of economically feasible and high efficient materials towards the oxygen evolution (OER) and reduction (ORR) reactions in alkaline media will constitute a major advancement in a variety of technologies such as water splitting, elctrowinning, fuel cells and metal-air batteries. OER and ORR have proven to be catalytic dependent electrochemical processes, and thus, the catalytic material at the oxygen electrode plays an important role in the performance of such technologies. Numerous research studies have been carried out on the synthesis of new electrode materials in order to reduce the voltage loss associated with the oxygen reactions.

In the present work, a comparison of OER behavior of a group of pyrochlore materials (A2B2O7-δ), and non-noble transition metal perovskites (ABO3) will be presented. The pyrochlore and perovskite structures were synthesized by a facile two-step combustion method yielding high purity phases with crystallite size in the vicinity of 20nm. The synthesized compounds include La1-xCaxFeO3, Pb2Ru2O7, and their substitutions, compared to un-supported RuO2 prepared by thermal decomposition of RuCl3. The catalysts powders were dispersed on a Nafion containing solution to form a catalyst ink [1]. The samples were tested in alkaline media in a traditional three-electrode system under continuous N2purging. Among the characteristics that make pyrochlores attractive for oxygen electrodes, is the unusual framework containing high density of oxygen vacancies and their apparent ordering which is believed to aid in the oxygen anion mobility [2]. Perovskite materials are attractive due to the wide range of substituting elements that can be employed to tune their electrocatalytic properties.

All the samples were characterized by XRD for phase analysis, XPS for valency, SEM for surface morphology. The OER electrochemical performance has been investigated by means of steady state current measurements. XRD spectra of selected samples and the OER activity are presented in Figure 1a and 1b, respectively. The effect of dopant concentration on the oxygen evolution activity will be discussed.

 Acknowledgements

This work is supported by the IGERT-NSF fellowship and partially funded by the US Department of Energy/NETL, Oak Ridge Institute for Science and Education (ORISE) fellowship.

References

[1] Malkhandi, S., Yang, B., Manohar, A.K., Manivannan, A., Surya Prakash, G.K., and Narayan, S.R., J. Phys. Chem. Lett. 2012, 3, 967-972.

[2] Hyoung Oh, S., Black, R., Pomerantseva, E., Lee, J-H., and F. Nazar, L. Nat. Chem. 2012, 4, 1004-1010.

Figure 1
New High Energy Capacity VB2/TiB2 Composite Transition Metal Boride Air Battery
Authors: Stuart Jessica , Lefler Matthew J. , Rhodes Chris , Licht Stuart
Published: February 2020

Transition metal borides, such as vanadium diboride (VB2) and titanium diboride (TiB2), are studied as alkaline battery anode materials both individually and as a composite anode for an air cathode battery. Composite batteries containing various amounts of VB2 and TiB2 show evidence of a synergistic enhancement of the cells both in their discharge voltage and in their efficiency. In alkaline media, VB2 and TiB2 individually electrochemically oxidize to yield 11 and 6 electrons per molecule, respectively. These anodes deliver an intrinsic gravimetric charge capacity of 4,060 mAh/g for VB2 and 2,314 mAh/g for TiB2, which is 3 to 5 fold higher than a typical zinc anode. High energy densities are obtained by using a cathode active material, oxygen, located outside the battery itself. The discharge of nanoscopic-VB2 shows a single voltage plateau of ~1V as a result of the simultaneous oxidation of all 11 electrons, though the coulombic efficiency (the actual charge capacity vs. the theoretical charge capacity) is greatly dependent upon the capacity of the anode; on the other hand, two distinct plateaus are reported for the macroscopic-TiB2 discharge curve (the first at ~1V, the second at ~0.85V), indicating the possibility of a two-step anodic oxidation occurring, but the coulombic efficiency of these cells remains constant despite changes in anode capacity.
Scalable Preparation of Freestanding Flexible Si Nanoparticles-Carbon Nanotubes Composite Paper Anodes for Lithium Ion Batteries and Their Prelithiation By Stabilized Lithium Metal Powder
Authors: Yao Kang , Zheng Jim P , Liang Richard
Published: February 2020

Freestanding flexible light-weight silicon nanoparticles-carbon nanotubes (SiNPs-CNTs) composite paper anodes for lithium ion batteries (LIBs) have been prepared by ultrasonication and pressure filtration without adoption of conductive additive, binder or current collector. Electrochemical testing has shown that the SiNPs-CNTs composite electrode material achieves first cycle specific discharge and charge capacities of 2298 and 1492 mAh/g, respectively. To address the first cycle irreversibility, stabilized lithium metal powder (SLMP) has been utilized to prelithiate our composite anodes. Compared to cell without SLMP, the cell with an SLMP loading of SLMP/anode mass ratio of 0.26 has the first cycle irreversible capacity loss reduced from 806 to 28 mAh/g and the first cycle coulombic efficiency increased from 65 to 98%. The relationship between different SLMP loading and the cell performance has been established to optimize the construction of Si-based cells. Use of the SiNPs-CNTs anodes incorporating SLMP as the source of lithium opens the door to a broad range of non-lithium-providing cathode materials and enables the creation of future high capacity and high energy LIBs.

Figure 1
Three-Dimensional Si-Based Composite Nanorods Array Applied in Energy Storage System
Authors: Li Jing , Yue Chuang , Yu Yingjian , Sun Shibo , He Xu
Published: February 2020

The rapid development of the integrated circuit (IC) and Micro/Nano-Electro Mechanical System (M/NEMS) technologies are promoting the continued emergence or commercialization of the miniaturized autonomous devices such as wireless sensor networks (WSN) in smart grid.[1-4] In order to operate independently, the micro/nano autonomous electronic devices must have on-board power supply. However, the battery miniaturization still can not keep pace with the size scaling-down of the CMOS electronic technologies, due to the poor electrochemical performance of the micro/nano batteries or the un-compatible battery fabrication process with the IC technologies. Currently, the transition from two dimensional (2D) to 3D rechargeable LIBs with better electrochemical properties in a small areal footprint was found to cope well with state-of-the-art semiconductor technologies conceptually providing new opportunities for micro/nano power systems in the future. [5-7]

In this work, the electrochemical performances of 3D hexagonal match-like Si/Ge nanorod (NR) arrays buffered by TiN/Ti interlayer, which were fabricated by a cost-effective, wafer scale and Si-compatible process, were demonstrated and systematically investigated as the anode in rechargeable batteries. The optimized Si/TiN/Ti/Ge composite NR array anode displays superior areal/specific capacities and cycling stability by reason of their favourable 3D nanostructures and the effective conductive layers of TiN/Ti thin films. Lithium/Sodium ion insertion behaviors were experimentally investigated in post-morphologies and elemental information of the cycled composite anode, and theoretically studied by the first principles calculation upon the adsorption and diffusion energies of sodium in Ge unit cell.  The preferential diffusion of Lithium/sodium in Ge structure over in Si lattice was evidently proved.

References:

[1]. Scott E. Thompson and Srivatsan Parthasarathy, materialstoday, 2006,  9, 20-25.

[2]. Yunhao Liu, Yuan He, Mo Li, IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, 24, OCTOBER 2013.

[3]. Jeffrey W. Long, Bruce Dunn, Debra R. Rolison, and Henry S. White, Chem. Rev., 2004, 104, 4463-4492

[4]. Timothy S. Arthur, Daniel J. Bates, Nicolas Cirigliano, Derek C. Johnson , Peter Malati, James M. Mosby, Emilie Perre, Matthew T.     Rawls, Amy L. Prieto, and Bruce Dunn, MRS Bull., 2011, 36, 523-531.

[5]. Loïc Baggetto, Harm C. M. Knoops, Rogier A. H. Niessen, Wilhelmus M. M. Kessels, and Peter H. L. Notten, J. Mater. Chem.,2010, 20, 3703-3708.

[6]. Alireza Kohandehghan, Peter Kalisvaart, Kai Cui, Martin Kupsta, Elmira Memarzadeha, and David Mitlin, J. Mater. Chem. A, 2013, 1, 12850-12861.

[7]. Peter H.L. Notten, Fred Roozeboom, Rogier A.H. Niessen, and Loïc  Baggetto, Adv. Mater., 2007, 19, 4564-4567.
Mn and Co Co-Substituted Fe3O4 Nanoparticles on Nitrogen-Doped Reduced Graphene Oxide for Oxygen Electrocatalysis in Alkaline Solution
Authors: Zhan Yi , Xu Chaohe , Lu Meihua , Liu Zhaolin , Lee Jim Yang
Published: February 2020

A dispersion of Mn and Co co-substituted Fe3O4 (MCF, Mn:Co:Fe=1:1:1) nanoparticles on nitrogen-doped reduced graphene oxide (N-rGO) nanosheets was prepared by a hydrothermal method. When tested for oxygen electrocatalysis in alkaline solution, the nanoparticles displayed 80% of the oxygen reduction reaction (ORR) activity of a typical 20 wt% Pt/C catalyst (Sigma); and 61% of the oxygen evolution reaction (OER) activity of a 20 wt% RuO2/C catalyst. Extensive material characterizations by field-emission transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICP-MS) were carried out to provide some understanding of the good electrochemical performance. The MCF catalyst has successfully integrated the ORR activity of manganese oxide, the OER activity of cobalt oxide; and the electronic conductivity of bulk Fe3O4 into an effective bifunctional catalyst; and its good contact with the N-rGO nanosheets also reduces the external transport resistance in oxygen electrocatalysis. Hence the MCF catalyst also delivered good performance in zinc-air full cell tests where they were used in the air electrode.
The Role of Modified Graphene in Cathode Formulations for Lithium-Ion Batteries
Authors: Arbizzani Catia , Da Col Luca , De Giorgio Francesca , Mastragostino Marina , Soavi Francesca
Published: February 2020

One of the main challenges in the development of lithium-ion batteries is to increase their specific energy by the use of high-voltage and high-capacity cathode materials. LiNi0.5Mn1.5O4 (LNMO) is one of the most promising materials with a theoretical specific capacity of 147 mAh/g and a Li+ deinsertion/insertion potential of 4.7-4.8 V vs Li+/Li. However, the use of LNMO raises the question of electrolyte decomposition at such a high potential with the consequent formation of a surface layer that affects the cathode and, hence, the cell performance. Interface stability issues are overcome by LiMxM1-xPO4 (LMP, with M=Fe, Mn) and Li3V2(PO4)3 (LVP) olivines, with Li+ deinsertion/insertion at potential ranging from 3.4 V to 4.5 V vs Li+/Li, that are widely investigated for their high specific capacity, near 170 mAh/g, and their intrinsic safety and environmental compatibility. However, the electronic and ionic conductivity of olivines need improvements.

We explored the effect of partially reduced graphene oxide on LNMO performance in conventional electrolyte [1] and here we investigate the role of modified graphene in LNMO- and LMP/LVP-composite materials. Morphological and structural characterization of the cathode materials and electrochemical tests of the corresponding electrodes will be reported and discussed.

[1] S. Monaco, F. De Giorgio, L. Da Col, M. Riché, C. Arbizzani, M. Mastragostino, J. Power Sources, submitted

Acknowledgments

The authors wish to thank ENEA and Italy’s Ministero dello Sviluppo Economico for financial support under the Program 2013 “Ricerca di sistema elettrico, Materiali catodici per batterie litio ione ad elevata energia”.
Constructing Anhydrous Hydrogen-Bonding Network in a Sulfonated Polymer Based Membrane for High Temperature Fuel Cell Applications
Authors: Li Yan , Wang Zhiyong , Hu Xiaohong , Chen George Zheng , Dai Sheng , Jin Xianbo
Published: February 2020

Proton exchange membrane fuel cells (PEMFCs) are most promising clean powers for vehicles.1 Current PEMFCs relying on Nafion with water necessary for proton conduction can only work below 363 K owing to that Nafion loses its conductivity quickly in response to the inevitable evaporation of water at elevated temperatures. However, PEMFCs operating at temperatures higher than 423 K are highly desired to overcome many obstacles of present PEMFCs, such as slow reaction kinetics, CO poisoning of the electrode catalysts, and the complexity of water and heat managements.2-4 Great efforts have been paid to develop anhydrous PEMs for these high-temperature FCs, particularly, those based on inorganic acids possessing intrinsic high proton conductivities at above 423K have been extensively studied.3,4 Intermingling sulfonated polymers (SPs, such as Nafion) with non-volatile, thermally stable (up to 573 K) ionic liquids (ILs) for anhydrous PEMs has also attracted numerous attention, and ionic conductivities exceeding 10-2 S cm-1 have been reached. However, these PEMs often suffer from low proton transfer numbers (0.5~0.6), poor mechanical performanc, and the assembed H2-O2 FCs with these ILs based PEMs were often poor in performance at intermediate temperatures.5,6

Here we report an anhydrous hydrogen-bond fusing strategy for high-performance PEMs by introducing hydroxyl functionalized IL (IL-OH) into the SPs. The IL-OHs selected as both proton donators and acceptors, that are evidenced to be strongly hydrogen-bonded with both Nafion and some nano-inorganic matters. Consequently, an effective interconnected hydrogen-bond network forms in a HFIL/SP based hybrid membrane, endowing the PEM with robust mechanical and thermal stability. At temperatures >430K , the anhydrous ionic conductivity of this kind of PEM can reach higher than 50 mS cm-1 with a large proton transfer number close to 1. And the initial high performance of the assembled intermediate-temperature H2-O2 FCs showed promising applications of this new generation HFIL/SP PEMs.

 

References

[1] M. Z. Jacobson, W. G. Colella, D. M. Golden, Science 2005, 308, 1901.

[2] Q. F. Li, C. Pan, J. O. Jensen, P. Noyé, N. J. Bjerrum, Chem Mater, 2007, 19, 350.

[3] J. A. Asensio, E. M. Sanchez, P. Gomez-Romero, Chem. Soc. Rev. 2010, 39, 3210.

[4] D. A. Boysen, T. Uda, C. R. I. Chisholm, S. M. Haile, Science 2003, 303, 68.

[5] M. Martinez, Y. Molmeret, L. Cointeaux, C. Iojoiu, J.-C. Leprêtre, N. El Kissi, P. Judeinstein, J.-Y. Sanchez, J. Power Sources
2010,195, 5829-5839;

[6] S. Y. Lee, A. Ogawa, M. Kanno, H. Nakamoto, T. Yasuda, M. Watanabe, J. Am. Chem. Soc. 2010, 132, 9764-9773
Corrosion Behavior of Stainless Steel Coated Graphene Layers for Polymer Electrolyte Membrane Fuel Cell Bipolar Plates
Authors: Lee Seokhee , Park Hyejin , Chung Yoonsung , Lee Eunji , Ahn Soohyun , Kim Dong-Joo
Published: February 2020

Metallic materials such as stainless steel are considering as a bipolar plate for polymer electrolyte membrane fuel cells (PEMFCs) due to their low bulk electrical resistivity, high heat conductivity, high mechanical strength, gas impermeability, low cost, and ability to produce thin sheets or foil (0.1 - 1 mm thick) form to achieve high power densities [1]. However, its corrosion resistance in working conditions of PEMFCs is still far from satisfaction. In addition, metal ions produced during the corrosion process decrease the ionic conductivity of Nafion®membrane and reduce the overall efficiency of a cell due to contamination of the catalysts [2]. Various coating materials such as ceramic-like nitride, carbides, conducting polymers, and surface modification of a substrate using thermal nitridation have been investigated to satisfy the requirements for bipolar plates [3]. Especially, carbon coating materials have received significant attention, because such materials supply excellent corrosion resistance, electrical conductivity and chemical stability in working conditions of PEMFCs [4]. In this study, carbon layers were coated on the surface of stainless steel plates to be used as bipolar plates in PEMFCs by spin coating system. Graphene oxide composite suspensions were used as coating materials. The graphene oxide layers were thermally reduced to increase the electrical conductivity. Microstructural analysis of the reduced graphene oxide layers were investigated by means of Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). For in-depth analysis of the corrosion properties, the electrochemical performance of the graphene coating layers was evaluated by the poteniodynamic method under simulated working conditions of PEMFCs, and the mechanism on corrosion resistance is discussed in detail.

References

[1] S.H. Lee, T.H. Tang, S.H. Hyun, Y.S. Yoon, Corros. Sci., 58 (2012) 79-85.

[2] S.H. Lee, V.E. Pukhac, V.E. Vinogradovc, N. Kakatia, S.H. Jee, S.B. Cho, Y.S. Yoon, Int. J. Hydrogen Energy, 38 (2013) 14284-14294.

[3] R. Taherian, J. Power Sources 265 (2014) 370-390.

[4] K. Feng, Z. Li, F. Lu, J. Huang, X. Cai, Y, Wu, J. Power Sources 249 (2014) 299-305.