bluuebunny/crossref_metadata_2025 huggingface dataset:
(Energy Technology Division Research Award) Electrolytes in Advanced Electrochemical Systems for Energy Storage and Conversion
Authors: Zawodzinski Thomas A.
Published: February 2020

The electrolyte in electrochemical systems plays a central role both literally and figuratively.  For low temperature systems, whether liquid or polymer electrolyte, the chemical and physical properties of this component has functions that go far beyond a linear ohmic response.  Non-linear aspects arise related to the role of water in devices such as fuel cells. The separator aspect of the membrane dictates that it play roles in mediating cross-over in multi-component systems.  In practical systems, the concentrated solutions to which a membrane might be exposed render a detailed understanding of its behavior critical.  And, of course, electrolytes must permeate through porous electrodes to complete the circuit and allow the primary transduction events to occur at an active electrode surface site.

These aspects play major roles in fuel cells, batteries and other electrochemical devices that are at the forefront of electrochemists’ contribution to the energy and environment fields in this symposium.  The scientist and engineer working on these devices often have two choices:  find a fundamental solution to the issue through developing advanced electrolytes or work around the problem with the materials at hand.  (I leave it to the reader to decide which choice would be favored by the scientist and engineer respectively!)  Nonetheless, each approach informs the other: it is important to have some sense of the underpinnings of the problem from each perspective.  As each new and potentially more complicated system is studied, it is necessary to review the available understanding of physical chemistry and transport of the electrolyte and, as needed, augment it.

In this presentation, after a brief overview of some early efforts and resolutions, examples of the state of the art of our understanding of electrolyte functions in redox flow batteries and in fuel cell electrodes will be presented.  Descriptions of processes occurring at scales from molecular to macro-scale will be presented.  Of particular interest in the flow battery context, and of general interest for electrosynthesis, is a description of the complex interplay between component interactions with each other and with membranes. For the fuel cell electrodes, unraveling of processes that connect structure and function at multiple levels is a primary unknown.  In particular, the behavior of ionomer within the layer and the relationship of that behavior to ionomer interactions with the other components will be discussed. 

Finally, in each case, these aspects will be placed in context of device-level issues that are caused and prospects for possible or actual solutions to these issues will be discussed.  To conclude reflections will be presented on issues that were ‘left behind’ incompletely resolved during development of some devices.
Preparation of Solar-Grade Silicon By Chemical and Electrochemical Processes
Authors: Homma Takayuki , Kunimoto Masahiro , Yang Xiao , Yasuda Kouji , Fukunaka Yasuhiro , Nohira Toshiyuki
Published: February 2020

As the demands for renewable energy have keep increasing, further massive production of solar-grade silicon (SOG-Si), which is key material for large scale solar cells, has been highly required.  Conventional process for its production is based upon carbo-thermic reduction of white silica ore followed by purification process by distilling chlorosilane species, which needs substantial energy consumption and having problems for lack of the resources.  For an alternative approach for this, we have developed a series of process to form the SOG-Si material based on the chemical purification of silica using aqueous solution [1] and electrochemical reduction using molten salt [2].  Here we will introduce our approaches for developing these processes.  For the source of SOG-Si, we focused on diatomaceous earth, which is earth-abundant material consisting of porous silica.  After wet chemical treatment with acid and alkaline solutions, most of the impurities except light elements such as B could be removed.  Then solvent extraction using channel-flow type reactor is applied for eliminating the light element with quite high efficiency, and the 7N level purity has been achieved [3, 4].  Then the silica was reduced by direct electrochemical reduction process using CaCl2 molten salt as an electrolyte, and crystalline Si was successfully obtained.  To develop a continuous production process, we designed the feeding system for silica powder and confirmed steady reaction for reducing silica to Si, and systematically investigated the reaction process for its optimization [5,6].

This work was supported by CREST, JST.

[1] M. Bessho, Y. Fukunaka, H. Kusuda, T. Nishiyama, Energ. Fuel., 23, 4160 (2009).

[2] T. Nohira, K. Yasuda, Y. Ito, Nature Material, 2, 397 (2003).

[3] N. Matsuo, Y. Matsui, Y. Fukunaka, T. Homma, J. Electrochem. Soc.,
161, E93 (2014).

[4] T. Homma, N. Matsuo, X. Yang, K. Yasuda, Y. Fukunaka, T. Nohira, Electrochim. Acta, 179, 512 (2015).

[5]          X. Yang, K. Yasuda, T. Nohira, R. Hagiwara, T Homma, J. Eelectrochem. Soc., 161, D1 (2014).

[6] X. Yang, K. Yasuda, T. Nohira, R. Hagiwara, T. Homma, Metall. Mater. Trans. B, in press.
Preparation of Cu2SnS3 Layers By Sulfurization of Electrodeposited Cu-Sn Multilayer Precursors
Authors: Sylla Diouldé , Creus Juan , Espindola-Rodriguez Moises , Placidi Marcel , Oliva Florian , Saucedo Edgardo , Perez-Rodriguez Alejandro
Published: February 2020

Semi-conductors of the Cu–Sn–S system are attracting great interest because of their promising photocatalytic activity, non linear optical properties and potential as photovoltaic p-type absorber.

Among the different ternary sulfides, Cu2SnS3 (CTS) is one of the most relevant compound for solar cell applications due to its high light absorption coefficient

(> 104 cm–1) and appropriate band–gap energy values between 0.93 and 1.35 eV dependent on the different crystal structure of the polymorphic compound. Different methods have been reported for the synthesis of CTS, such as conventional solid-state reaction [1] and solvothermal process [2], mainly for powder preparation, whereas thin films have been deposited by spray pyrolysis technique [3], and also from direct sulfurization of sputter deposited [4] or electrodeposited [5] metal precursors.

Electrodepostion (ED) has a strong interest because of its relatively easy scalability to industrial processes and its potential for reduction of costs in relation to vacuum based technologies.

In this communication, we report the preparation and characterization of ternary CTS thin films using a sequential ED of Cu and Sn metallic layers onto Glass/Mo substrates in different deposition sequences and number of sublayers ((Cu/Sn)k and (Sn/Cu)k, k = 1; 2) followed by a thermal annealing treatment under S containing atmosphere.

The properties of the CTS absorber are strongly influenced by the morphological and structural characteristics of the metallic stacks precursors that depend on the ED operating conditions. In this case, the influence of electrolyte formulation and applied potential on the microstructure and morphology of the Cu–Sn precursors will be deeply studied. Then, we will investigate in detail how the stacking order of the precursor films affect the microstructure and optical properties of the resultant CTS absorbers. Moreover, our preliminary results of the growth of CTS thin films obtained by an alternative ED approach that we still develop in our laboratory, will be report and compare with the results obtained from a more conventional ED synthesis discussed above.

[1]. M. Onoda, X. Chen, A. Sato, H. Wada, Mater. Res. Bull. 35, 1563 (2000)

[2]. B. Li, Y. Xie, J. Huang, Y. Qian, J. Solid State Chem. 153, 170 (2000)

[3] M. Adelifard, M. Mehdi, B. Mohagheghi, H. Eshghi, Phys. Scr. 85, 035603 (2012)

[4] P.A. Fernandes, P.M.P. Salom, A.F. da Cunha, J. Phys.
D Appl. Phys. 43, 215403 (2010)

[5] D.M. Berg, R. Djemour, L. Gutay, S. Siebentritt, P.J. Dale, X. Fontane, V. Izquierdo-Roca, A. Pérez-Rodriguez, Appl. Phys.
Lett
. 100, 192103 (2012)
(Keynote) Formulation for the Treatment of Multiple Electrochemical Reactions and Associated Speciation for the Lithium-Silicon Electrode
Authors: Verbrugge Mark W , Baker Daniel R , Xiao Xingcheng
Published: February 2020

We develop a theory and commensurate equations to model the thermodynamics, electrochemistry, and species transport of substitutional alloys subject to multiple electrochemical reactions, and we apply the treatment to the lithium-silicon (Li-Si) system [1].  The approach is general in that we expect it is applicable to simulate the electrochemical-reaction behavior of known substitutional-alloy and insertion-electrode materials of interest relative to today’s and near-future electrode materials.  Central to the approach is the treatment of slow-scan voltammetry to gather information usually obtained by data differentiation associated with differential voltage spectroscopy; we show that the approach taken here allows for an accurate description of very low-rate behavior (0.01 mV/s), which we refer to as dynamic equilibrium (see Fig. 1).

We employ directly the experimental results from [1], corresponding to a silicon thin-film (67 nm) electrode deposited on a copper current collector. CR2032 coin cells were assembled with the Si thin film as the working electrode and a lithium foil as the counter-reference electrode.

To construct the model in [1], a look-up table was employed to evaluate the variation in the open-circuit potential with lithium content.  In the current work, we develop consistent thermodynamic and electrochemical-reaction treatments that capture the salient features of the Li-Si experimental data and should prove to be of general utility for the treatment of substitutional alloys and insertion electrodes [2]. We employ the low-scan-rate voltammetry data reported in [1], which simplifies material balances, as diffusion resistance is negligible, and species concentrations are uniform throughout the film, although they vary with time. Last, we provide a discussion of results, including a perspective on the potential implications of the proposed treatment (with an emphasis on how the thermodynamic treatment influences transport relations based on the Stefan-Maxwell framework) and important open questions.  The model is shown to compare favorably with experimental results obtained from thin-film Li-Si electrodes conducted at moderate potential-scan rates, with irreversible behavior governed by charge-transfer (interfacial) resistance; cyclic voltammetry results are shown in Fig. 2.

 

M. Verbrugge, D. Baker, X. Xiao, Q. Zhang, and Y-T. Cheng, “Experimental and theoretical characterization of electrode materials that undergo large volume changes and application to the lithium-silicon system,” J. Phys. Chem. C., 119(2015)5341.

M. Verbrugge, D. Baker, and X. Xiao, “Formulation for the treatment of multiple electrochemical reactions and associated speciation for the lithium-silicon electrode,” J. Electrochem. Soc., 163(2016)A262-A271.

Figure 1
First Principles Computational Study of Active and Stable Electrocatalysts for Oxygen Reduxtion and Evolution Reactions
Authors: Han Byungchan , Noh Seunghyo , Hwang Jeemin
Published: February 2020

Using first principle density functional theory calculations we show how to search highly active nonprecious catalysts for oxygen reduction reactions in acidic and alkaline media. It is clearly propose that both the activity and stability can be enhanced with novel computational design principles based on ab-inito methods. We also propose that a perovskite oxide with mixed oxidation states in transition metals is a good candidate for oxygen evolution reaction, which is key reaction in water splitting process storing energy in the fuels.
Mathematical Models for the Impedance Response of Subcutaneous Glucose Sensors
Authors: Harding Morgan , Orazem Mark E. , Tribollet Bernard
Published: February 2020

Since 1974, the artificial pancreas has been acknowledged by the greater scientific community to be a possible way to manage type 1 diabetes [1]. In 2008, a case study showed that a subcutaneous continuous glucose monitor sensor could be implanted for 28 days in a patient with type 1 diabetes [2]. However, commercially available subcutaneous continuous glucose monitors are generally changed every seven days to avoid unreliable results. The object of this work is to explore the potential of impedance spectroscopy to monitor the state of health of subcutaneous continuous glucose monitor sensors.

A mathematical model has been developed for the impedance response of a glucose oxidase enzyme-based electrochemical biosensor. The model accounts for a glucose limiting membrane GLM, which controls the amount of glucose participating in the enzymatic reaction.  The glucose oxidase was assumed to be immobilized within a thin film adjacent to the electrode. In the glucose oxidase layer, a process of enzymatic catalysis transforms the glucose into peroxide, which can be detected electrochemically. This system may be considered to be a special case of the coupled homogeneous and heterogeneous reactions addressed by Levich [3].

The model development required two steps. The nonlinear coupled differential equations governing this system were solved under the assumption of a steady state. The steady-state concentrations resulting from the steady-state simulation were used in the solution of the linearized set of differential equations describing the sinusoidal steady state. The enzymatic catalysis was treated in terms of two homogeneous reactions, one consuming the glucose oxidase and forming gluconic acid, and the other regenerating the glucose oxidase and forming the peroxide.

References

A. M. Albisser,  B. S. Leibel,  T. G. Ewart,  Z. Davidovac, C. K. Botz, and W. Zingg, Diabetes 23 (1974), 389–396.

J. J. Chamberlain and D. Small, Clin. Diabetes, 26 (2008), 138–139.

V. G. Levich, Physicochemical Hydrodynamics, Prentice Hall, Englewood Cliffs, NJ, (1962), p. 345-357.
Understanding the Pseudocapacitive Behavior of RuO2 from First Principles
Authors: Keilbart Nathan D. , Dabo Ismaila
Published: February 2020

The ever increasing power of electronic devices creates a taxing demand on energy storage technology to increase the energy and power density available. Typical energy storage devices that have met this demand in the past are batteries and capacitors. A growing need for high energy and power dense materials leads to a new set of devices called pseudocapacitors, typically made from battery electrode materials but on a nanometer scale, which push the limit of both energy and power density available in a single device. The charge storage system of pseudocapacitors can be broken into several parts: double-layer capacitance, underpotential deposition, redox and intercalation pseudocapacitance which occurs through quick intercalation and surface redox reactions on the electrode.1 Therefore, to maximize the capabilities of pseudocapacitors the surface area must be increased for double-layer capacitance as well as allowing fast and reversible faradaic reduction-oxidation reactions. The exact nature of these redox reactions are not fully understood with respect to the oxidation state of the atoms. A typical pseudocapacitor material is Ruthenium Oxide (RuO2) which exhibits great pseudocapacitor properties but becomes expensive when looking to make on a large scale. The goal of this work is to better understand the material properties of pseudocapacitive materials, such as RuO2, that permit them to have the qualities of a pseudocapacitor as opposed to that of a battery. To do this work, the use of highly efficient and high throughput computation models, such as density functional theory (DFT), are used to proficiently calculate material properties in order to exclude material systems that do not meet designated outcomes. A particular method of interest for this process is the Self-Consistent Continuum Solvation model (SCCS)2 which allows DFT to correctly model the dielectric properties of a solvent. From the values calculated in DFT we are able to predict the change in the Gibbs free energy as well as the change in the chemical potential of the system as the surface of the material is covered with ions. Furthermore, charged surface calculations allow for the prediction of the change in the material properties at different levels of coverage3 and charge. For future and current work we would apply these models to pseudocapacitor systems to examine if they have intrinsic properties or if the material could be manipulated on the structural level to have the abilities of an extrinsic pseudocapacitor.

References

1.        Augustyn, V., Simon, P. & Dunn, B. Pseudocapacitive oxide materials for high-rate electrochemical energy storage. Energy Environ. Sci.
7, 1597 (2014).

2.        Andreussi, O., Dabo, I. & Marzari, N. Revised self-consistent continuum solvation in electronic-structure calculations. J. Chem. Phys.
136, 064102 (2012).

3.        Bonnet, N. & Marzari, N. First-principles prediction of the equilibrium shape of nanoparticles under realistic electrochemical conditions. Phys. Rev. Lett.
110, 1–5 (2013).
(Invited) The Use of Modeling to Reveal Root-Cause and Quantify Degradation Effects in Electrochemical Systems
Authors: Fuller Thomas F
Published: February 2020

Electrochemical systems are characterized by coupled, non-linear behavior of several phenomena.  Typically, thermodynamics, kinetics, and mass-transfer all come in to play in describing the current voltage response of a system.  This strong coupling can make interpretation of experimental results confounding and cause our intuition to fail us.  Through, mathematical modeling, the nature of the response is more easily revealed.  This concept is explored through two real-world applications of electrochemical systems: start-stop phenomena in fuel cells and power fade in lithium-ion batteries. 

Corrosion of carbon support during start-up and shut-down of proton-exchange-membrane fuel cells is well-known and widely reported in the literature.  Today, this is an accepted degradation mechanism.  However, the journey from severe performance loss observed in a fuel-cell vehicle to our present understanding was difficult.  In fact, measurements of cell potential and current did not help elucidate the mechanism at all.  It was only through mathematical modeling that the corrosion process was clarified.  No new physics was needed, just the careful assembly of existing knowledge of kinetics and transport for a start-up transient.

Capacity fade in lithium-ion batteries is also a well-known issue.  Generally, the formation and slow growth of the solid electrolyte interphase (SEI) results in irreversible consumption of lithium.  This loss of cyclable lithium translates into a reduced capacity of the battery with age.  In addition to capacity fade, power fade is critical for many applications.  A prime example is the battery for a charge-sustaining hybrid-electric vehicle. Here, the energy storage system is used for recovering energy and power assist, not sustained propulsion of the vehicle.  Therefore, power capability is at least if not more important than capacity. The power capability is characterized by “cell resistance.”  As the SEI thickness grows, the ohmic resistance of the cell increases.  However, the magnitude of the increase cannot explain the power fade.  Typically, for a pulse of current of ten or so seconds is used in practice to measure “cell resistance.”  For transients of this length, this quantity is not simply the ohmic resistance of the cell--concentration polarizations are significant.  This behavior is explored with well-established mathematical models of lithium-ion cells.  Again, a mathematical model that uses existing physics is able to shed light on the nature of the power fade.
Beaded Mn2O3 Nanofibers by Electrospinning for Supercapacitor Applications
Authors: Kolathodi Muhamed Shareef , Voigt Victoria , Singh Gurpreet
Published: February 2020

We report a surfactant-free method for the synthesis of beaded manganese oxide (Mn2O3) nanofibers by electrospinning and their application in supercapacitors. Beaded morphology of the fibers by annealing was observed through electron microscopic analysis. High crystalline nature and lattice strain of the fibers were verified by X-ray analysis and high resolution transmission electron microscopy (HRTEM). X-ray photoelectron spectroscopy and Raman Spectroscopy techniques were used to characterize the Mn2O3 nanofibers. Electrochemical properties of Mn2O3 nanofibers for use as electrodes in supercapacitors were investigated using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy in a 0.5 M Na2SO4 aqueous electrolyte. The specific capacitance of the Mn2O3 beaded nanofibers was found to be 358 Fg-1 at a current density of 0.5 Ag-1. Lattice strain-induced ionic and electronic defects enhanced the surface properties of the Mn2O3 nanofibers, thereby improving the electrochemical properties for supercapacitor applicaions.
Lithium Ion Battery Electrode Fabrication via Additive Manufacturing
Authors: Wang Yan , Liu Jin
Published: February 2020

In our research, the lithium ion battery electrodes were manufactured using a new powder painting process, which is completely dry. No solvents are applied, which is necessary in the conventional slurry-cast electrode manufacture. Thermal activation time has also been tremendously reduced due to a lowered time and resource requirement when the solvent evaporation process in conventional method is replaced by a hot rolling process. It has been found that inducing the mechanical bonding of the thermoplastic polymer to the remaining active electrode particles only takes a few seconds for the thermal activation step. Furthermore, skipping the traditional drying process allows large-scale Li-ion battery production to be more economically viable in markets. Electrochemical results also show that the tested electrodes with our method outperform conventional slurry processed electrodes, which is due to a better binder distribution. In addition, bonding tests of the dry-deposited particles onto the current collector show that the bonding strength is greater than slurry-cast electrodes, 127.14 kPa as compared to 84.29 kPa.
Treatment of Wastewater Containing Sulfa Drug by Photo Active Anode (Ti/Ru0.3Ti0.7O2) in Photo-assisted Electrochemical Process
Authors: Hussain Sajjad , Gul Saima , Steter Juliana R. , Motheo Artur de Jesus
Published: February 2020

Drug residues are unregulated pollutants and are frequently found in the aquatic environment. Due to their extensive use, presence in the aquatic environment and their potential for impacts on wildlife and humans, it is becoming an important environmental issue. The present study evaluates the photo-assisted electrochemical treatment of sulfamethoxazole (SMX), an antibiotic used in the prevention and treatment of human and animal diseases. The experiments were carried out in a photo illuminated flow cell reactor and the effects of current density and concentration of sodium chloride in the supporting electrolyte were determined. The Drug could be removed completely at all current densities while TOC abatement was appreciable during the process. The process followed pseudo-first order kinetics and values of electrical energy-per-order were dependent on current density and sodium chloride concentration. Different reaction intermediates were separated and identified by liquid chromatography coupled with mass spectrometry (LC-MS), thereby providing an insight into the mechanistic details of the degradation pathway. The photo-assisted electrochemical degradation proceeded through competitive reactions such as chlorination, hydroxylation and substitution on the aromatic ring, while further ring opening gave rise to more simple organic compounds and, ultimately, the mineralization of SMX. The possible degradation route were also proposed and discussed.

Figure 1
(Invited) New Li Ion Cells with Extended Temperature Range
Authors: Ma Chengsong , Peres Jean-Paul
Published: February 2020

Saft developed a new Li ion cell limiting cell aging between -40oC and 85oC. It avoids Li deposition, electrodes de-percolation & swelling.

This new cell design address issue of the state of art Li ion cell which are not able to work both at LT (-20°C and below) and at HT (+60°C to +85°C), without a strong cell electrical performances degradation. It sustains a long calendar life or floating period at 4.1V-4.2V @ 60°C, without a strong electrical performances degradation, and/or a rapid opening of the circuit breaker  in link with internal cell gas generation. It limits cell self heating at end of discharge during high rate discharge at elevated temperature environment. It has 10 years life floating at 4.2V. This cell has three layers of safety protection and compliance to international safety standard.
(Invited) Aqueous Interphase Enables Safe, Green and Low Cost Li-Ion Chemistry
Authors: Suo Liumin , Borodin Oleg , Wang Chunsheng , Xu Kang
Published: February 2020

The interphases play a key role in enabling Li-ion intercalation chemistries in non-aqueous electrolytes, in which solvents reduction mainly contribute the chemical building blocks 1, 2. Recently Suo et al discovered for the first time that such protective interphases could be formed in aqueous media via manipulation of the Li-ion solvation structure 3. This discovery opened a window to an entirely new world, and makes it possible to employ aqueous electrolytes to replace the inflammable and toxic non-aqueous components that induces huge cost in processing, safety management as well as packaging 4. This talk will summarize the newest progress achieved in this new direction.

 

 K. Xu, Chem. Rev.,
2004, 104, 4303

 K. Xu, Chem. Rev.,
2014, 114, 11503

 L. Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, C. Luo, C. Wang, and K. Xu, Science,
2015, 350, 938

 L. Smith, and B. Dunn, Science,
2015, 350, 918
Lithium Plating: Root Cause, Post-Mortem Characterization, and Key Parameters to Exclude It in Automotive Applications
Authors: Waldmann Thomas , Hogg Bjoern-Ingo , Kasper Michael , Wohlfahrt-Mehrens Margret
Published: February 2020

Deposition of metallic Li on graphite anodes is a critical aging mechanism happening in Lithium-ion cells during charging at low temperatures, high C-rates and high states-of-charge [1,2]. Furthermore, Li deposition can also have negative effects on cell safety [3]. The cause for deposition of Li on anodes are negative anode potentials vs. (Li/Li+). Unfortunately, anode potentials are not accessible in commercial cells since they do not contain a reference electrode. In half cells such measurements are also not possible, since the interaction between anode and cathode is absent. Furthermore, the position of the reference electrode between anode and cathode is very important to measure anode potentials correctly [4] (Figure (a)).

In the present talk, we show that it is possible to reconstruct both, anodes (graphite) and cathodes (NMC/NCA) from commercial cells (16Ah pouch/3.25Ah 18650-type) into 3-electrode full cells with an additional Li reference electrode (Figure (a)). With these 3-electrode cells, it is possible to measure the anode potentials vs. (Li/Li+) for all important combinations of operating parameters: (i) temperature, (ii) charging C-rate, and (iii) end-of-charge voltage. Data evaluation results in parameter sets which can exclude Li deposition on anodes (Figure (b)). The data extracted from the 3-electrode full cells are in agreement with long-term cycling tests and with Post-Mortem analysis of the original commercial cells. Furthermore, the data from the 3-electrode full cells allow to extend the cycle life of the original commercial cells significantly.

References:

[1] J.C. Burns, D.A. Stevens, J.R. Dahn, J. Electrochem. Soc. 162 (2015) A959-A964.

[2] T. Waldmann, M. Kasper, M. Wohlfahrt-Mehrens, Electrochim. Acta 178 (2015) 525-532.

[3] M. Fleischhammer, T. Waldmann, G. Bisle, B.-I. Hogg, M. Wohlfahrt-Mehrens, J. Power Sources 274 (2015) 432–439.

[4] B.-I. Hogg and M. Wohlfahrt-Mehrens, in Meeting Abstracts, The Electrochem. Soc. (2015), 343 .

Figure 1
(Invited) Dry Electrode Process Technology
Authors: Duong Hieu , Suszko Arek , Feigenbaum Haim
Published: February 2020

Within this decade, there has been immense effort focused on reducing the cost of energy storage devices. The goal towards energy independence through electrification of automobiles for widespread adoption has greatly incentivized this endeavor. Strategies ranging from novel materials investigation to advanced device manufacturing development span the cost reduction effort. Maxwell Technologies is actively engaged in this global effort from the direction of dry electrode fabrication technology. Maxwell dry electrode technology offers manufacturing cost and performance competitiveness, and novel battery chemistry enablement. This paper provides the initial foundation and validation for the application of dry coated electrode in lithium-ion batteries.

Maxwell Technologies is a San Diego based ultracapacitor manufacturer that uses a proprietary liquid-free electrode production process. Advanced process development without the need for solvents has enabled Maxwell’s dry electrode production lines to operate at high throughput using a minimal manufacturing footprint. This unique electrode manufacturing process does not introduce any volatile waste products into the atmosphere or require complex manufacturing plant arrangement. It begins with dry raw materials compounding and maintains its liquid-free state throughout the subsequent processing steps to ultimately produce a robust high-performance ultracapacitor electrode. Since this process produces a dry active material free-standing film, the scrap is collected and reused in the successive processing batches.

Maxwell is currently engaged in research and development efforts to expand the application space of its dry electrode process technology to include battery electrode manufacturing. Cell performance using prototype dry coated lithium-ion battery electrodes has been demonstrated under two DOE funded programs. Electrode configuration with various architectures using a wide range of materials can be produced at thicknesses ranging from about 50 microns to about 1 millimeter. In addition to manufacturing flexibility, the cohesion and adhesion properties of electrodes derived from the dry process are superior in the presence of electrolyte at high temperatures compared to those produced using the wet coating technology.

This unique electrode process technology offers significant saving in manufacturing cost and helps curb CO2 pollution during the battery electrode manufacturing process. By eliminating the use of any liquids/solvents, and the associated coating and drying complexity inherent in wet processing, the dry electrode process is environmentally friendly, and can be readily installed and commissioned with a much lower start-up capital investment. Thus, dry electrode manufacturing is economically attractive and socially responsible.

This paper will provide insight into dry electrode coating technology and its capacity for the enablement of advanced battery chemistries, and cell performance results derived from dry coated lithium-ion battery electrodes.
Two-Dimensional Layered Materials with Expanded Interlayer Distance for Rechargeable Magnesium Batteries
Authors: Li Yifei , Liang Yanliang , Yao Yan
Published: February 2020

Mg rechargeable batteries (MgRBs) stand out as a promising candidate beyond lithium ion battery technologies due to high volumetric energy density, resource abundance, and the dendrite-free deposition behavior of Mg, which ensures safe operation. Many of the advantages of MgRBs originate from the divalent nature and small ionic size of Mg ions; however, these properties also render the cation too polarizing to diffuse easily in most ion- intercalation materials. To overcome this challenge, we recently adopted an interlayer expansion approach via insertion of external pillars to transform two representative two-dimensional layered materials (MoS2 and V2O5) into efficient Mg storage host materials.

To boost the Mg storage performance of MoS2, we intercalated appropriate amount of poly(ethylene oxide (PEO) to expand MoS2 structure through an exfoliation and restacking process. [1,2] The Mg solid state diffusivity and capacity increased accordingly with increasing amount of PEO. PEO2L-MoS2 (two layers of PEO in between MoS2 layers) showed the best performance with Mg2+ diffusivity increase by two orders of magnitude and capacity increase of about 300% compared with bulk MoS2. The flexible PEO serves as a structure pillar, which can increase the interlayer spacing but not block the diffusion of Mg2+ ions. In the case of V2O5, we turned to insert small water molecules in the layered structure to take advantage of the shielding effect of H2O.[3] We prepared graphene decorated V2O5 aerogel nanowires, and demonstrated it to be an effective cathode material, with specific capacity of 330 mAh g-1 at low rate, stable cyclability and good rate performance. The performance enhancement compared with bulk V2O5 is due to the increased space and charge shielding effect of crystal water in the aerogel to enhance the Mg2+ insertion and the porous structure of aerogel allowing easy access of electrolyte into the active material. Moreover, various interlayer spacing and crystal water amount were also studied and we found that the as-prepared sample with the highest amount of water and interlayer spacing showed the best performance.

The merit of the interlayer expansion lies at the enlarged space for enhanced Mg2+ ion mobility and weakened interaction between Mg2+ ions and the electrode frameworks. This approach could be further extended to a wide range of host materials for the storage of Mg2+ ion and other multivalent ions. 

1. Yanliang Liang, Hyun Deog Yoo, Yifei Li, Jing Shuai, Hector A. Calderon, Francisco Carlos Robles Hernandez, Lars C. Grabow, and Yan Yao, Nano Lett.
2015, 15, 2194-2202.

2. Yifei Li, Yanliang Liang, Francisco C. Robles Hernandez, Hyun Deog Yoo, Qinyou An, Yan Yao, Nano Energy 
2015, 15, 453-461.

3. Qinyou An, Yifei Li, Hyun Deog Yoo, Shuo Chen, Qiang Ru, Liqiang Mai, and Yan Yao, Nano Energy 
2015, 18, 265-272.
Peanut Shell Hybrid Sodium Ion Capacitor with Extreme Energy - Power Rivals Lithium Ion Capacitors
Authors: Mitlin David
Published: February 2020

ABSTRACT: This is the first report of a hybrid sodium ion capacitor (NIC) with the active materials in both the anode and the cathode being derived entirely from a single precursor: peanut shells, which are a green and highly economical waste globally generated at over 6 million tons per year. The electrodes push the envelope of performance, delivering among the most promising sodiation capacity - rate capability - cycling retention combinations reported in literature for each materials class. Hence the resultant NIC also offers a state-of-the-art cyclically stable combination of energy and power, not only in respect to previously published NICs but also as compared to Li ion capacitors (LICs). The ion adsorption cathode based on Peanut Shell Nanosheet Carbon (PSNC) displays a hierarchically porous architecture, a sheet-like morphology down to 15 nm in thickness, a surface area on par with graphene materials (up to 2396 m2g-1) and high levels of oxygen doping (up to 13.51 wt%). Scanned from 1.5 - 4.2 V vs. Na/Na+ PSNC delivers a specific capacity of 161 mAhg-1 at 0.1A g-1 and 73 mAhg-1 at 25.6 Ag-1. A low surface area Peanut Shell Ordered Carbon (PSOC) is employed as an ion intercalation anode. PSOC delivers a total capacity of 315 mAhg-1 with a flat plateau of 181 mAhg-1 occurring below 0.1 V (tested at 0.1 Ag-1), and is stable at 10,000 cycles (tested at 3.2 Ag-1). The assembled NIC operates within a wide temperature range (0 - 65°C), yielding at room temperature (by active mass) 201, 76 and 50 Wh kg-1 at 285, 8500 and 16500 W kg-1, respectively. At 1.5 - 3.5 V, the hybrid device achieved 72% capacity retention after 10,000 cycles tested at 6.4 Ag-1, and 88% after 100,000 cycles at 51.2 Ag-1.
Polyimide Derivative As Electrolyte Additive to Improve Electrical Performance and Safety in Lithium-Ion Batteries
Authors: Chang Max Yu-hao , Chu Peter Po-jen
Published: February 2020

A new type of electrolyte additive, the hyperbranched polyimine derivative (p-BPMI) is prepared from 1,3-dimethyl-barbituric acid (1,3-DBTA), copolymerizing of bismaleamic acyl imide (BMI) and N-phenylmaleimide(PMI). The p-BPMI powder is dissolvable in electrolyte (1M LiPF6 in EC+DMC+EMC 1:1:1 V/V %), and administered similarly as other electrolyte additives. The interface composition and SEI structure after pre-cycling the coin cells using the Li(Ni1/3Mn1/3Co1/3)O2/Li half cell were characterized by SEM、EIS and XPS techniques and confirmed that the hyper-branched p-BPMI participated with the growth of SEI, where both the electrolytes and salt decomposition are reduced, leading to the formation of thinner and more robust SEI coating.

With addition of 1wt% p-BPMI in electrolyte, the capacity retention is improved from 85.21% to 96.53% compared with the base electrolyte after 0.5C-rate for 80 cycles at 25°C. Cycling at 0.5C-rate at 60oC for 30 cycle, the capacity retention is improved from 93.71% to 96.43% when compared with 1wt% VC.  NMC/graphite pouch full cell (500mA) with 1wt% p-BPMI-added electrolyte in the fully charged state at 4.3V shows no sign of combustion or explosion after induce internal shortage by puncturing the cell, while the regular cell with only VC additive is exploded.  This new type of electrolyte additive p-BPMI not only improved the room and high temperature cycling performance, it also assured LIBs safety.

Figure 1
Tuning Ionic Clusters in Sulfide Glass-Ceramics for Superior Solid-State Electrolytes
Authors: Kim Hyoungchul , Cho Soo-Young , Lee Yoon-Sung , Jung Hun-Gi , Lee Jong-Ho , Lee Hae-Weon
Published: February 2020

The all-solid-state lithium batteries (ASSLBs) have drawn increasing interests and demands as the next-generation rechargeable batteries for electric vehicles and energy storage devices since they have much more potentials (e.g., higher safety, reliability, power density, and design flexibility) than conventional lithium batteries. However, all we know any further advances in ASSLBs are not possible without solving the current raising issues of ASSLBs, such as low lithium ion conductivity, structural instability, and high resistance of electrode/electrolyte interface. Especially, the unveiling the mechanism of lithium ion conduction in solid electrolytes, and the development of a superior solid-state lithium ion conductor are required.

Here we present the recent advances and understandings in Li-P-S based solid electrolytes for the next-generation ASSLBs using a novel atomistic alloying and annealing process. Employing the low-temperature milling and quantitative bulk/surface analyses, we demonstrate the tuning ionic structures in sulfide glass-ceramics for superior solid-state electrolytes, and unveil the roles of atomistic alloying in the mechanochemical pulverization and high-temperature annealing in the amorphous-crystal transition to seek the highly active, stable, and versatile Li-P-S based solid electrolytes. Controlling ionic structures and understanding such atomistic alloying and annealing effects of lithium super-conducting sulfides provides insights for designing advanced solid electrolyte materials. We also believe these research activities lead to the promising technological advances and provide new guidelines in developing the sulfide based solid electrolyte for ASSLBs.
A Vanadium Redox Flow Battery for Hydrogen Production
Authors: Girault Hubert
Published: February 2020

A vanadium/cerium redox flow battery is used with two external circuits to ensure a chemical discharge of the electrolytes to maintain on optimum state-of-charge of the battery even in the case of electricity overproduction.

A first reactor is dedicated to hydrogen production whilst the second is dedicated to oxygen evolution.

In the first reactor, the Vanadium(II) solution in sulfuric acid is passed over a catalyst made of Mo2C to generate hydrogen under pressure.

In the second reactor, theCerium (IV) solution in sulfuric acid is apssed over a catalyst made of RuO2 to generate oxygen.

The theory underlying these electrochemical reactions on a floating catalyst will be discussed. Experiments on a 10 kWh scale will be presented.

In addition, we shall present our experience at coupling a 50 kW alkaline electrolyser with a 200kW Vanadium redox flow battery to run a service station for electric vehicles and hydrogen fuel cell cars.
Thin Film Li-Ion Microbatteries Using Self-Supported Titania Nanotubes
Authors: Djenizian Thierry
Published: February 2020

Nowadays, lithium-ion batteries (LIBs) are widely used to power portable devices, microelectronics, vehicles, etc.  With many advantages such as high surface area and improved charge transport, self-supported 3-D nanostructured metal oxides are promising electrode materials for LIBs and their impact is particularly significant when considering the miniaturization of energy storage systems and the development of 3D microbatteries [1-3].

During this talk, it will be presented the fabrication and use of materials derived from self-organized titania nanotubes (TiO2nts) as negative 3D self-supported electrodes for microbatteries [4–8]. This kind of 3D nanostructured electrodes is particularly interesting due to better electrochemical performance in terms of kinetics and stability during cycling.

Then, the fabrication of an all-solid-state Rocking-chair battery composed of vertical arrays of TiO2nts as anode, a polymer thin film as electrolyte, and a LiNi0.5Mn1.5O4 (LNMO) layer as cathode will be shown [9]. According to the electrochemical tests, this 2D full-solid microbattery showing an operating voltage of 2.1V exhibits high performance such as good discharge capacity and good capacity retention.

Finally, the current approaches developed to achieve the fabrication of a full 3D microcell will be highlighted. Particularly, the conformal electrodeposition of polymer electrolytes into tha titania nanotubes and their potential filling will be discussed [10-12].

References

[1]           B.L. Ellis, P. Knauth, T. Djenizian, Adv. Mater., 26 (2014) 3368.

[2]           L. Baggetto, J.F.M. Oudenhoven, T. van Dongen, J.H. Klootwijk, M. Mulder, R. a. H. Niessen, M.H.J.M.    de Croon, P.H.L. Notten, J. Power Sources 189 (2009) 402.

[3]           M. Nathan, D. Golodnitsky, V. Yufit, E. Strauss, T. Ripenbein, I. Shechtman, S. Menkin, E. Peled,             Microelectromechanical Syst. J. 14 (2005) 879.

[4]           G. Ortiz, I. Hanzu, T. Djenizian, P. Lavela, J.L. Tirado, and P. Knauth, Chem. Mater. 21 (2009) 63.

[5]           N.A. Kyeremateng, C. Lebouin, P. Knauth, T. Djenizian, Electrochim. Acta 88 (2012) 814.

[6]           N.A. Kyeremateng, V. Hornebecq, P. Knauth, T. Djenizian, Electrochim. Acta 62 (2012) 192.

[7]           T. Djenizian, I. Hanzu, P. Knauth, J. Mater. Chem. 21 (2011) 9925.

[8]           N.A. Kyeremateng, N. Plylahan, A.C.S. dos Santos, L. V Taveira, L.F.P. Dick, T. Djenizian, Chem.Commun. 49 (2013) 4205.

[9]           N. Plylahan, M. Letiche, M. Barr, and T. Djenizian, Electrochem. Commun., 43, 121 (2014).

[10]        N. Plylahan, N.A. Kyeremateng, M. Eyraud, F. Dumur, H. Martinez, L. Santinacci, P. Knauth, T. Djenizian, Nanoscale Res. Lett. 7 (2012) 349.

[11]        N. Plylahan, A. Demoulin, C. Lebouin, P. Knauth, T. Djenizian, RSC Adv., 5, 28474 (2015).

[12]        N. Plylahan, M. Letiche, M. Barr, B. Ellis, S. Maria, T. N. T. Phan, E. Bloch, P. Knauth, and T. Djenizian, J. Power Sources, 273, 1182 (2015).
Highly Soluble, Sometimes Liquid, Electron-Donating Phenothiazines for Batteries with Non-Aqueous Electrolytes
Authors: Odom Susan A , Casselman Matthew D , Kaur Aman Preet , Elliott Corrine F , Chapman Steven , Zhang Peter , Risko Chad
Published: February 2020

Phenothiazines have seen widespread use as stable electron-donating organic compounds with generally stable oxidized states, making them an amenable core for functionalization toward electrochemical energy storage applications. With phenothiazine itself as a starting material, functionalization of the 3, 7, and 10 positions is facile, providing options to modify redox potentials and improve stability in both the neutral and singly oxidized (radical cation) states.  In one to three steps, we can create highly soluble, stable derivatives that are suitable for applications requiring the donation of one or two electrons. We have observed thousands of hours of overcharge protection in lithium-ion batteries and more recently have moved into testing these species as the electro-active materials for non-aqueous redox flow batteries. This presentation will focus on the synthesis and characterization of new derivatives, highlighting new results in which we found that a liquid phenothiazine that can be prepared in one step from commercially-available starting materials can serve as an electron donor and solvent, dissolving some lithium salts to concentrations of at least 1 M.
Incorporation of Pyridinium Axial Ligands for Fe Phthalocyanines Anchorage on Carbon Nanotubes Electrodes for Biomimetic Oxygen Reduction
Authors: Oyarzun Maria Paz , Silva Nataly , Silva Juan Francisco , Ramirez Sara , Zagal Jose H
Published: February 2020

Metallo phthalocyanines confined on electrode surfaces such as graphite and carbon materials have been used extensively as active molecular catalysts for a variety of reactions1. When anchored on carbon nanotubes the activity of these catalysts increases by almost 2 orders of magnitude in part due to an increase in effective area. Recently, Cao et al. have shown that anchoring FePc to carbon nanutubes using an axial ligand produces very active materiales for the reduction of O2 in alkaline media, mimicking in this fashion the function of cytochrome c in the catalytic reduction of O2 in living systems. In this work we have used iron phthalocyanines (FePcs) for O2 reduction in basic medium incorporated single wall carbon nanotubes (SWCNTs) modified with pyridiniums axial ligands (py) obtained by reacting diazonium salts. The two phthalocyanines used correspond to the unsubstituted iron phthalocyanine FePc and perchlorinated iron phthalocyanine (16(Cl)FePc)).

Our results show that for ORR:

(i) As expected, carbon nanotubes produce a pronounced increase in electrode surface area, favoring the incorporation of more active sites of the molecular catalysts studied.

(ii) The incorporation of the axial ligand causes an increase in the rate of ORR, resulting in the onset for ORR to more positive values compared to the response of electrodes having FePcs without the axial ligand..

(iii) Of the studied phthalocyanines, 16(Cl)FePc exhibits the highest catalytic activity (Fig.1) due to the synergistic effect of Cl electron withdrawing substituents and the electron withdrawing pyridinium axial ligand.  

Acknowledgment:
Fondecyt Nº
1140192 and postdoctoral proyect Nº 3150271.

1.              Zagal, J. H., Griveau, S., Silva, J. F., Nyokong, T. & Bedioui, F. Metallophthalocyanine-based molecular materials as catalysts for electrochemical reactions. Coord. Chem. Rev.
254,2755–2791 (2010).

2.              Cao, R. et al. Promotion of oxygen reduction by a bio-inspired tethered iron phthalocyanine carbon nanotube-based catalyst. Nat. Commun.
4, 2076 (2013).

Figure 1