bluuebunny/crossref_metadata_2025_split 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.
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.
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
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