bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) High Temperature Flexible Supercapacitors
Authors: Park Ho Seok , Rana Harpalsinh H. 
Published: February 2020

With increasing demand for high performance energy storage systems, the feasibility of reliable and functional energy storage devices that well operates under extreme conditions is of prime importance for expanding applicative fields as well as for understanding materials’ intrinsic and extrinsic properties and device physics. Our group has been investigating ultracapacitive energy storage materials and devices operating under limited circumstances, where conditions are classified into thermodynamic (e.g. pressure, volume and temperature) and kinetic (e.g. high rate and frequency) variables. In this talk, I will introduce high temperature operating, flexible supercapacitors based on graphene electrodes and polymer or gel electrolytes that can efficiently deliver electrical energy under electrochemical, mechanical and thermal stresses.[1-4] In order to achieve high performance supercapacitor devices under thermal, mechanical and electrochemical stresses, the micro- and macroscopic structures and chemical compositions of graphenes are delicately controlled by chemical modification. For the case of electrolyte materials, both of electrochemical properties and mechanical integrity should be satisfied for high temperature device applications. A new generation of flexible supercapacitors, with the long-term durability and outstanding electrochemical properties, were realized, showing a high position of the Ragone plot, even under severe conditions.

References

[1] B. G. Choi, J. Hong, W. H. Hong, P. T. Hammond, ACS Nano, 5, 7205-7213 (2011).
[2] B. C. Kim, J. Y. Hong, G. G. Wallace, H. S. Park, Adv. Energy Mater, 5, 1500959 (2015).
[3] S. K. Kim, H. J. Kim, J. C. Lee, P. V. Braun, H. S. Park, ACS Nano, 9, 8569-8577 (2015).
[4] J. Y. Hong, B. M. Bak, J. J. Wie, J. Kong, H. S. Park, Adv. Funct. Mater., 25, 1053-1062 (2015).
The Frst Molecular Dumbbell Consisting of an Endohedral Sc3n@C80 and an Empty C60-Fullerene Building Block
Authors: Wei Tao , Hirsch Andreas 
Published: February 2020

An unprecedented hybrid dumbbell consisting of a metallofullerene and an empty fullerene was afforded via simple click reaction of suitable precursor derivatives of Sc3N@C80 and a C60 hexakisadduct. The structure of synthetic endohedral clusterfullerene-based dumbbell was unambiguously characterized by MALDI-TOF mass spectrometry and 1H NMR spectroscopy. The electronic structure was carefully studied by UV-vis-NIR spectroscopy revealing its exceptional electronic behaviour compared to parental building blocks. In combine with the electronic property study of congener dimer on basis of solo C60, the peculiar electronic property of dumbbell is unveiled. Our success on the first construction of endohedral clusterfullerene dumbbell opens up a new perspective in fullerene chemistry.
Scheme 1: Schematic synthesis route of dumbbell

Figure 1
(Invited) Synthesis of Graphene-C60 Hybrids
Authors: Langa Fernando 
Published: February 2020

The combination of two carbon nanostructures in a single material, giving rise to new hybrids with improved mechanical, electrical, and thermal properties, has generated great interest in the last years. Although hybrids carbon nanotubes have been described, hybrids between graphene and fullerenes have received less attention.
In this talk, I´ll present our recent studies involving the synthesis of nanohybrids combining exfoliated Graphene and C60, as well as the new properties arising from the combination of both carbon nanomaterials.
(Invited) Purification and Frontier Orbital Characterisation of 19 Isomers of the OPV Acceptor Material Bis[60]PCBM
Authors: Dennis John , Shi Wenda , Hou Xueyan , Liu Tong 
Published: February 2020

All 19 expected cyclopropa-fullerene isomers of the organic photovoltaic electron acceptor material bis-phenyl-C62-butyric acid methyl ester ("bisPCBM") have been isolated from the as-produced isomer mixture by peak-recycling high pressure liquid chromatography to a purity exceeding 99.5%, and their frontier orbitals characterised by UV-Vis absorption spectroscopy and cyclic voltammetry.
Using purified isomers in bisPCBM-based OPVs is expected to yield an increase in efficiency through the removal of energetic disorder and the removal of morphological disorder contributing to higher device currents; and through the using on isomers with higher LUMOs than the average for the isomer mixture contributing to an increase in device voltage. On the latter point above, an important factor in OPV efficiency is that the open-circuit voltage (“V
OC”) of OPVs scales linearly with the energy difference between the highest occupied molecular orbitals (“HOMOs”) of the donors and the lowest unoccupied molecular orbitals (“LUMOs”) of the acceptors. Hence, for a given donor, VOC is proportional to the LUMO level.
The LUMOs of the purified isomers were found to vary from -3.90 to -3.73 eV. As such, all isomers have LUMOs are above that of PCBM (-3.92 eV). Furthermore, the LUMOs of 13 of the 18 isomers are above that of the isomer mixture (-3.82 eV). OPV devices based on each of those 13 individual isomers will each have a higher V
OC than that of present devices based on the mixture. One isomer, with a LUMO ca. 100 meV above that of the mixture (and ca. 200 meV above that of PCBM), is particularly promising.
Preliminary results on two unoptimized P3HT/BisPCBM OPV devices based on the most abundant isomer with (a) a below average LUMO, and (b) an above average LUMO, gave V
OCs of 0.77 V and 0.83 V, respectively; which compares favourably with V
OCs of 0.63 V and 0.73 V of fully optimized P3HT/PCBM and P3HT/bisPCBM devices, respectively.
Metal Oxides As Additives to Improve Anode Performance in Molten Carbonate Fuel Cells (MCFC)
Authors: Beyad Yaser , Islam Monirul , Glenn Michael , Mathan Bobby , Allen Jessica A , Donne Scott W 
Published: February 2020

In molten carbonate fuel cells (MCFC), oxidation of solid carbon fuels takes place at extended three-phase boundary (TPB) as molten carbonate electrolyte enhances the reaction interface in the anode compartment of the cell and facilitates diffusion of reactants. It also acts as an electrochemical mediator in oxidising carbon or carbon monoxide to carbon dioxide. Several studies have already been conducted to improve electrolyte’s performance in anode by either changing its composition or adding additives, i.e. metal oxides. Electrolyte composition effect, in terms of using different metal carbonates and their quantity in the mixture, on the performance of MCFC has been extensively investigated in the literature. However, comparing different additives effect on the overall performance of a cell using available data in the literature is not viable. This is because of lack of consistency in previous studies’ experimental conditions and specifically in anode composition. Also, there is not an agreement on mechanism that metal oxides improve the performance of MCFCs.
In the current study, two different percentages (5 and 10 wt%) of SnO2, CeO2, Fe2O3, and Mn2O3 were used as additives to electrolyte and fuel mixture of the anode. Performances of the full cell with different additives were evaluated in the same conditions using polarisation (IV) and electrochemical impedance spectroscopy (EIS) tests. In addition, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) were performed on anode slurry samples to further investigate details of the interactions between the anode electrolyte components. Based on the results, we provide a clear comparison on the effectiveness of these metal oxides in improving the cell performance and also suggest a mechanism that metal oxides enhance performance of anode in molten carbonate fuel cells.
(Battery Division Student Research Award sponsored by Mercedes-Benz Research & Development) Revisiting the Electrochemical Stability Window of Solid Electrolytes
Authors: Han Fudong 
Published: February 2020

The development of next-generation batteries has raised higher requirements on safety and energy density, both of which can be potentially improved by developing solid-state batteries (SSBs). Significant advances have been made in achieving superionic solid electrolytes (SEs) with a wide electrochemical stability window (ESW) from 0 to 5 V. The ESW of solid electrolytes was usually measured from cyclic voltammetry of Li/SE/inert metal semi-blocking electrode. Because of the wide ESW, solid electrolytes hold great promise for high energy density batteries with high columbic efficiency and long cycle life.
In this presentation, we challenge the claimed ESW of solid electrolytes. The conventional method to measure ESW provides an overestimated value because the kinetics of the electrochemical decomposition reaction is limited in the semi-blocking electrode. A novel experimental method using Li/SE/SE+carbon cell is proposed to approach the intrinsic stability window of solid electrolytes. The ESWs of Li10GeP2S12 (LGPS) and Li7La3Zr2O12 (LLZO), the most promising SE for sulfide and oxide electrolytes respectively, are examined using the novel experimental method. The results suggest that both SEs have much narrower electrochemical stability window than claimed (Figure 1). The cathodic and anodic decomposition products for both electrolytes are also characterized. The measured stability window and the decomposition products agree well with the calculated results from first principles. The reversible decompositions of LGPS at both high and low voltages enable the realization of a battery made from a single material.
The electrochemical decompositions of the SEs in SSBs can lead to large interfacial resistances between electrode and electrolyte, depending on the properties of the decomposition products. The interfacial resistances arising from the decomposition of SEs have rarely been considered in previous research because the batteries are cycled within the “claimed” stable window of SEs. Suppressing the (electro)chemical reactions between LiCoO2 cathode and LLZO electrolyte by engineering their interphase enables a high performance all-ceramic lithium battery. By taking advantage of the electrochemical decomposition of SEs, an effective approach to suppress Li dendrite formation in sulfide electrolyte is also demonstrated.
References
[1] F. Han, Y. Zhu, X. He, Y. Mo, C. Wang,
Adv. Energy Mater., 6 (2016) 1501590.
[2] F. Han, T. Gao, Y. Zhu, K. J. Gaskell, C. Wang,
Adv. Mater., 27 (2015) 3473.
[3] F. Han, J. Yue, C. Chen, N. Zhao, X. Fan, Z. Ma, T. Gao, F. Wang, X. Guo, C. Wang,
Joule, 2 (2018) 497.
[4] F. Han, J. Yue, X. Zhu, C. Wang,
Adv. Energy Mater., (2018) 1703644.
Atomic Layer Deposition of ORR Catalysts for Rechargeable Zinc-Air Batteries
Authors: Clark Michael Patrick , Cadien Ken , Ivey Douglas G 
Published: February 2020

The move towards cleaner and renewal energy production, such as solar and wind power, necessitates the development of efficient, safe and cost effective energy storage methods. Zinc-air batteries (ZABs) are prime candidates to meet these requirements and store large amounts of electricity. They use oxygen in the atmosphere as the cathode reactant in the discharge process. Oxygen diffuses into the cell and is reduced to hydroxyl ions in the presence of a catalyst at the air electrode (oxygen reduction reaction or ORR). At the same time, the zinc electrode is oxidized and dissolves in the electrolyte, producing zincate ions. During recharging, zinc metal is reduced from zincate ions and plated at the zinc electrode. Oxygen evolution (OER) occurs at the air electrode. There are challenges in implementing zinc-air batteries for large scale energy storage. The ORR and OER processes at the air electrode are sluggish and electrode stability can be poor because of catalyst delamination and/or substrate corrosion during battery cycling. Effective electrodes for ZABs require a catalyst that is efficient, stable and electrochemically active.
Atomic layer deposition (ALD) is a gas phase deposition technique capable of fabricating thin films from a wide variety of materials. ALD utilizes alternating pulses of reactants that each undergo self-limiting reactions on the sample surface, producing uniform and conformal films, with good composition control and sub-nanometer thickness control. These features of ALD are particularly attractive for fabricating ORR catalysts in zinc-air battery electrodes, as they can lead to increased surface areas and three-phase boundary areas, both of which should lead to better performance and cyclability. In this study, ALD is used to produce air electrodes with Mn oxide as the ORR catalyst. The process is optimized and deposits are characterized using microstructural characterization (e.g., electron microscopy, X-ray diffraction, surface science techniques and Raman spectroscopy) and electrochemical characterization (e.g., linear sweep voltammetry, electrochemical impedance spectroscopy and galvanostatic cycling) methods. Successful materials are tested in two different battery configurations, i.e., a two electrode set-up and a three-electrode set-up where the ORR and OER reactions are decoupled. The three-electrode configuration limits the potential window to which each electrode is subjected, greatly improving stability and cyclability.
Fast Charging Strategy Based on Electrochemical Model and Dynamic Programming for a Lithium-Ion Battery Cell
Authors: Xu Meng , Wang Xia 
Published: February 2020

Fast charging technology of lithium-ion batteries is critical to commercial application of electrical vehicles (EV). Typically, recharging lithium-ion batteries using standard charging methods takes more than one hour which is considerably longer than refueling of the internal-combustion-engine (ICE) car, roughly 8-10 min. To reduce the charging time, fast charging increases the total current which can adversely affect the cycle life, performance and safety of the battery, such as lithium plating, increased battery temperature, higher heat generation rate, and thermal runaway. The charging energy efficiency can be reduced because of the increased heat generation during fast charging. Therefore, controlling the temperature rise and improving the charging energy efficiency using well-designed fast charging strategies are indispensable for its application in electric vehicles.
The objective of this work is to optimize the charging current profile based on electrochemical thermal model and dynamic programming for a 26650 cylindrical lithium iron phosphate (LFP) battery. The proposed model is implemented on a multi-stage constant current (MSCC) fast charging strategy for charging from 0 % to 80 % of its rated capacity within 30 minutes. The goal of the optimization is to maximize the charging energy efficiency or/and minimize the temperature rise and charging voltage. The control variable of various charging current protocols using the C-rate level ranging from 0.6 C-rate and 2.6 C-rate are applied to the MSCC fast charging. The constraints of the optimization include temperature and cell voltage, which are applied to prevent thermal runway and reduce the capacity fade. The optimized charging current profile based on various initial temperatures, ambient temperatures, and heat transfer coefficients will be compared. In addition, the effect of constraints on optimization results will be discussed.
To study the effect of fast charging based on the battery dynamics, the electrochemical model first proposed by Newman et al. has been addressed. Even though the electrochemical model is not suitable for online application, the results can serve as a benchmark to evaluate and improve an existing online algorithm for battery fast charging optimization. However, few of those works using electrochemical models discussed the effect of fast charging strategies on battery electrochemical and thermal behavior, as well as charging energy efficiency under various charging current patterns.
Based on dynamic programming and electrochemical thermal model, this research proposes a new method to optimize charging current profile under various constraints and different optimization goals, which are useful for fast charging application of lithium-ion batteries on electric vehicles.
Piezoelectrochemical Energy Harvesting in Commercial Lithium Ion Batteries
Authors: Preimesberger Juliane Irine , Kang SeungYeon , Arnold Craig B. 
Published: February 2020

As technology becomes smaller and smaller, the need for micro-energy sources becomes increasingly imperative. One promising technology to address this need is piezoelectrochemical harvesting, a recently identified mechanism to directly convert mechanical energy to electrochemical potential[1-4]. In piezoelectrochemical (PEC) materials, the chemical potential of ions is affected by an applied stress, and under such circumstances these materials can be used in a thermodynamic cycle to harvest energy, at a relatively slow rate commensurate with the kinetic transport in electrochemical systems. Previous work[1] has demonstrated that commercial lithium cobalt oxide (LCO) batteries exhibit the PEC effect, as both the lithium cobalt oxide cathode and lithium-intercalated graphite anode are PEC materials. The coupling factor between the change in equilibrium potential and applied mechanical stress has been found to be linear.
In this presentation, we will discuss our research to use piezoelectrochemical energy harvesting to increase the voltage generated from commercial lithium ion batteries. We measured the differential expansion and differential voltage of a lithium ion battery, and used this data to estimate the coupling factor as a function of state-of-charge (SOC). We analyzed the coupling factor for commercial LCO batteries, and found the SOC where the coupling factor was maximized. At this SOC, batteries were placed under a mechanical load to harvest energy. The voltage generated was quantified by measuring the voltage drop across a resistor. To understand how the PEC effect operates in multiple batteries, we wired cells in series and parallel, and performed similar mechanical load experiments. As expected, the PEC voltage can be increased by compressing batteries in series. Increasing the PEC voltage generated would allow the effect to be used in practical applications such as micro-energy devices.

References:

[1] J. Cannarella and C. B. Arnold, “Toward Low-Frequency Mechanical Energy Harvesting Using Energy-Dense Piezoelectrochemical Materials," Advanced Materials, 27, 7440 (2015).
[2] S. Kim, S. J. Choi, K. Zhao, H. Yang, G. Gobbi, S. Zhang, and J. Li, “Electrochemically driven mechanical energy harvesting," Nature Communications, 7, 10146 (2016).
[3] N. Muralidharan, M. Li, R. E. Carter, N. Galioto, and C. L. Pint, “Ultralow Frequency Electrochemical−Mechanical Strain Energy Harvester Using 2D Black Phosphorus Nanosheets,”

ACS Energy Lett., 2, 1797 (2017).
[4] E. Jacques, G. Lindbergh, D. Zenkert, S. Leijonmarck, and M. H. Kjell, “Piezo-Electrochemical Energy Harvesting with Lithium-Intercalating Carbon Fibers,” ACS Appl. Mater. Interfaces,
7, 13898 (2015).
Use of Lithium Iron Phosphate (LFP) Batteries As Piezoelectrochemical Materials to Increase Low-Frequency Mechanical Energy Harvesting
Authors: Kang SeungYeon , Preimesberger Juliane Irine , Arnold Craig B. 
Published: February 2020

Efficient energy harvesting from nonconventional sources is increasingly important these days where energy usage is continuously rising and providing power to newly developed electronic systems require nontraditional power sources. Piezoelectrochemical (PEC) materials undergo a volume change as a result of an electrochemical reaction and can be expected to produce orders of magnitude more energy per volume than conventional piezoelectrics due to the high energy density associated with Faradaic reactions. Through maximizing PEC effect, one may be able to achieve great advancement in the energy harvesting research field. In this work, we utilize off-the-shelf lithium iron phosphate (LFP) battery pouch cells to study and maximize the conversion of mechanical energy to electrochemical energy.
Previously we proposed that stress and voltage are linearly related by a PEC coupling factor, k , which is defined as the change in equilibrium potential Uo of an electrochemical reaction with respect to change in applied stress σ. This factor, k can also be expressed in terms of the mechanical strain ε produced from an electrochemical reaction involving volumetric charge qv which shows that the coupling between stress and voltage is a consequence of the work of mechanical expansion due to the electrochemical motion of charged species. As a result, larger harvested energy density can be associated with high k values and high volumetric capacities and this physically corresponds to materials that exhibit high expansion with flat discharge voltage curves. We choose LFP batteries that have flat voltage curves to experimentally demonstrate the concept of mechanical energy harvesting through the piezoelectrochemical coupling. We show that the expansion mostly originating from the graphite anode combined with the flat voltage characteristics of the LFP cathode result in a higher energy yield.
Failure Analysis of the Rechargeable Porous Zinc Electrode in Alkaline Electrolyte
Authors: D'Ambrose Michael , Yadav Gautam Ganapati , Turney Damon , Gallaway Joshua W , Nyce Michael , Messinger Robert J. , Banerjee Sanjoy 
Published: February 2020

Metallic zinc (Zn) is an attractive negative electrode material for rechargeable batteries because it is a non-toxic, earth abundant metal. It has a low equilibrium potential of -1.35 V vs. mercury-mercuric oxide (Hg/HgO) in concentrated alkaline electrolyte and a high gravimetric discharge capacity of 820 mAh/g. During discharge, Zn oxidizes and forms a dissolved complex known as the zincate ion, Zn(OH)4
2-, from which zinc oxide (ZnO) precipitates as a solid. On charge, Zn(OH)4
2- is reduced to metallic Zn. Motivation to study the Zn electrode in rechargeable batteries is driven by a target overall battery energy density of 200 Wh/L that is sustainable for 500 or more charge-discharge cycles. This corresponds to a Zn electrode discharge density in the range of 650 mAh/mL.
The cycle life of the porous Zn electrode in concentrated alkaline electrolyte is observed to decrease with increasing percentage of discharge capacity of Zn accessed. The percentage of discharge capacity of Zn accessed is known as the depth of discharge (DOD). Zn electrodes were cycled in the range of 1% to 15% Zn DOD in zinc-manganese dioxide (Zn-MnO2) batteries and in the range of 15% to 30% Zn DOD for zinc-nickel (Zn-Ni) batteries. Additives were incorporated into the zinc electrodes for the tests done on Zn-Ni batteries. Additives used were surfactant cetyltrimethylammonium bromide (CTAB), bismuth oxide (Bi2O3), synthetic layered silicate Laponite, and calcium hydroxide (Ca(OH)2). The potential values of the Zn electrodes vs. Hg/HgO reference electrodes were recorded.
During healthy galvanostatic discharge, Zn electrodes displayed a nearly constant potential vs. Hg/HgO at approximately -1.35 V. Tests that failed due to Zn exhibited a shift from this equilibrium potential that corresponded to a loss of cell voltage. This shift may be attributed to concentration overpotential as ZnO is precipitated, thereby inhibiting the hydroxide ions from reaching the reacting metal interface. The shift may also be due to formation of a passivated layer on the electrode which effectively blocks the remaining active material. There are generally two regimes observed in the potential curves of the Zn electrode vs. Hg/HgO prior to cell failure. Beyond the healthy plateau at -1.35 V, the first regime consists of a sloping potential while the second regime is an additional plateau. The second plateau shifts with increasing cycle number and corresponds to cell death. See the attached figure for discharge curves of a Zn electrode cycled at 5% Zn DOD. The second plateau is believed to be due to passivation of the Zn electrode. The additives were observed to modify the discharge potential curve of the Zn electrode vs. Hg/HgO.

Figure 1