bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring Different Avenues of Microbattery Fabrication through Electrodeposition
Authors: Rehnlund David , Asfaw Habtom Desta , Sun Bing , Böhme Solveig , Valvo Mario , Wei Wei , Oltean Gabriel , Brandell Daniel , Edström Kristina , Nyholm Leif 
Published: February 2020

Microbattery research sparked from the rapid expansion and miniaturization of micromelectromechanical systems (MEMS) has recently produced a wide variety of different cell designs and electrode geometries. Three-dimensional (3D) electrodes are currently the most promising approach addressing the requirement of high energy and power density on a limited surface area. Expansion in the third dimension offers an increased surface area thereby enabling high energy density without substituting rate performance [1]. Dense packing of all microbattery components offers short diffusion length for charge carriers, e.g. Li-ions and electrons, while contributing to the decrease of the overall cell volume [2].
Of all the techniques studied so far, template-assisted fabrication is the most common route to achieve nanostructured electrodes. By such means, electrodeposition has been used to grow nanopillar [3] and aperiodic ‘sponge’ electrodes.
This work presents results from our studies on electrochemical fabrication of nanostructured electrodes based on nanopillar and aperiodic design as well as integration of a polymer electrolyte coating. Both nanostructured anodes and cathodes will be presented based on the core current collector of carbon, aluminium and copper.

Acknowledgements

This work has been supported by the STandUP for Energy project, the Swedish Energy Agency (STEM), and the Swedish Research Council (VR).

References

1. K. Edström, D.B., T. Gustafsson, L. Nyholm, Electrodeposition as a Tool for 3D Microbattery Fabrication. The Electrochemical Society Interface, 2011. 20: p. 41-46.
2. R.W. Hart, H.S. White., B. Dunn, D.R. Rolison, 3-D Microbatteries. Electrochemistry Communications, 2003. 5: p. 120-123.
3. M. Valvo, M. Roberts., G. Oltean, B. Sun, D. Rehnlund, D. Brandell, L. Nyholm, T. Gustafsson, K. Edström, Electrochemical elaboration of electrodes and electrolytes for 3D structured batteries. Journal of Materials Chemistry A, 2013. 1: p. 9281-9293.
Electrodeposition Based Synthesis of Metal-Air Battery Cathodes
Authors: Marschilok Amy C , Takeuchi Esther S , Takeuchi Kenneth J 
Published: February 2020

Metal air batteries offer the opportunity for unprecedented energy density improvements relative to existing battery technologies. Air cathodes are usually comprised of a catalyst, conductive additives, binder, and current collector. The current collector provides support and conductivity, the binder provides physical adhesion, and the catalyst facilitates the oxygen reduction process at the cathode. Thus, each component plays an important role in the function of the overall electrode. Additionally, access of the catalyst particle to oxygen is critical, so the cathode porosity must be appropriately tuned. Electrodes are often fabricated using physical mixing methods, where issues can include poor interparticle contact and limited access of the interior catalyst particles to oxygen.
An electrodeposition based strategy for fabrication of a composite air cathode will be discussed. The first layer consists of a current collector substrate, which can be two dimensional (planar) or three dimensional in design. The second layer consists of a conformal conductive polymer coating. The third layer consists of catalyst particles. The second and third layers are each prepared using stepwise deposition processes.
Advantages of the electrodeposition fabrication method will be described. Three-dimensionally structured composites can be easily generated via use of three dimensional substrates. All of the catalyst nanoparticles are positioned on the outer surface of the composite electrode, allowing facile access of oxygen gas molecules to the catalyst particle surfaces. Finally, the conductive polymer provides added conductivity and improved stability to the composite. Resulting impact on conductivity and oxygen reduction activity of the composite electrode will be discussed.

References

1. S.H. Lee; S. Zhu; C.C. Milleville; C.-Y. Lee; P. Chen; K.J. Takeuchi; E.S. Takeuchi; A.C. Marschilok. Electrochem. Solid-State Lett.
2010,
13(11), A162-A164.
2. A.C. Marschilok; S. Zhu; C.C. Milleville; S.H. Lee; E.S. Takeuchi; K.J. Takeuchi. J. Electrochem. Soc.
2011,
158(3), A223-A226.
3. A.C Marschilok; S.H. Lee; C.C Milleville; P. Chen; E.S Takeuchi; K.J Takeuchi. J. Composite Materials.
2012,
47(1), 33–40.
Comparison of Aqueous and Non-Aqueous Deposition of Cobalt Via Electroplating Method
Authors: Abdel-Fattah Tarek M , Huff Clay , Dushatinski Thomas 
Published: February 2020

The purpose of this study is to compare the deposition of cobalt onto a copper substrate from aqueous and non-aqueous cobalt chloride solutions. The aqueous solution had a pH of 2 and had an equal concentration of cobalt as the non-aqueous. The non-aqueous solution consisted of a 2:1 molar ratio ethylene glycol to choline chloride solution.
Deposition was performed for 10, 15 and 30 minute intervals with both solutions at 3 volts potential difference between the copper plate and reference. The suitable electroplating temperatures were found to be 70° C for the non-aqueous solution and 22° C for the the aqueous. The aqueous was initially run at 70° C to keep the temperature variable constant, but was found incapable of producing consistent films and was run at a lower temperature of 22° C. The coating deposited by the non-aqueous solution was black of color and had controllable thickness based on time. The aqueous coating was shiny silver, and was measured to be thinner than that of the non-aqueous films, but still had controllable thickness.
The black cobalt thin films could have applications in optical systems to reduce parasitic light. Also the non-aqueous has applications in thermal active solar cells as they are conductive and absorb a wide range of the electromagnetic spectrum emitted by the sun, converting it to applicable thermal energy. The metallic looking cobalt thin films could be applied as mirrors in x-ray optics systems after polishing, as they may have different angles of diffraction.

Referencies:

1Florea, A.; Anicai, L.; Costovici, S.; Golgovici, F.; Visan, T. 2010, Surf. Interface Anal, 42, 1271-1275

2Abdel-Fattah, T.M.; Crooks, R. SurfaceCharacterization of High Purity Niobium Electropolished with an Ionic Liquid. 2010, ECS Trans, 33, 571

3Abdel-Fattah, T.M.; Loftis, J.D. Surface Characterization of High Purity Metals of Silver and Nickel Electropolished with an Ionic Liquid. 2010, ECS Trans, 25, 57

4Ionic Liquid Electropolishing of Metal Alloys for Biomedical Applications. Abdel-Fattah, T.M.; Loftis, J.D.; Mahapatro, A. 2010, ECS Trans, 25, 57

5Abdel-Fattah, T.M.; Loftis, J.D. Comparison of the Electrochemical Polishing of Copper and Aluminum in Acid and Acid-free Media. 2009, ECS Trans. 25, 327

6Damiano, B.; Wixtrom, A.; Abdel-Fattah, T. Electrochemical Deposition of Cobalt onto the Surface of Copper Using a Choline Chloride-Based Ionic Liquid. 2012,
ECS Trans. 50(11) 277-281
Thermal Analysis of High-Power Prismatic LiFePO4 batteries: Modeling and Experiment
Authors: Yazdanpour Maryam , Taheri Peyman , Bahrami Majid 
Published: February 2020

A 90Ah prismatic LiFePO4/graphite battery (Sinopoly Battery Ltd., China) is used for the experiments and thermal modeling [cf. Fig. 1].
In the experimental study, a power processing system is employed to cycle the experimental battery. Constant-current discharge tests at 1C-rate (90A), 2C-rate (180A), and 3C (270A) are performed to measure the battery voltage and surface temperatures.
In the modelling study, a three-dimensional transient model has been developed to predict the thermal behaviour of the battery during galvanostatic processes. A transient heat conduction equation is sufficient to describe the thermal phenomenon of domain (1); while the heat transfer mechanism in domain (2) is modelled by the natural convection. A convective-radiation boundary condition is considered at the boundaries of the domain.
The above-mentioned models are performed in a finite element solver (COMSOL Multiphysics, Version 4.4), and the accuracy of the model is validated through comparison with the experimental data.

Some Results

The rate of heat generation which is the main parameter calculation in the thermal model, is approximated from [1],

g=I/ν[(V-V
oc
)+T
dV
oc/dT] (1)
where I and V denote the battery operational voltage and current, respectively, ν represents the battery volume, V
oc
is the open circuit voltage of the battery and T
is

temperature. The heat generation terms can be determined by using experimental tests or electrochemical models, which the first approach is applied in this study. A constant value of -0.4337 mV/K adapted from Ref. [2], is considered for term dV
oc/dT. The rate of heat generation caused by the polarization losses, V-Voc
, is defined from the measured electrical performance of the battery.
The heat generation rates inside the battery (domain (1)) during three different galvanostatic discharge processes (90 A, 180 A, and 270 A) are calculated based on Eq. (1) and the battery electrical performance, and then the obtained expressions are implemented into the thermal model.
In Fig. 2, the modeling results for average surface temperature of the battery (shown by solid lines) are compared to the corresponding experimental data (symbols), during constant-current discharge processes with 90 A, 180 A, and 270 A. The comparison shows an excellent agreement between the predicted results and the data from the experiments.
In future, an electrical model will be coupled to the presented model to describe the ohmic heating in the electrodes as a result of the electrical constriction resistance.
[1] D. Bernardi, J. Electrochem. Soc., Vol. 132, pp. 5-12, (1985).
[2] A. Samba et al. , J. Electrochimica Acta, Vol. 117, pp. 246–254, (2014).
[3] P. Taheri et al., J. Electrochem. Soc., Vol. 160, pp. A1731–A1740, (2013).
Influence of Surface Treatments on the Electrochemical Reactivity of VO2+/VO2
+ Redox Couple Using Carbon Fiber Ultramicroelectrodes
Authors: Miller Mallory Arlene , Savinell Robert F. , Wainright Jesse S. 
Published: February 2020

Several surface treatments for flow battery electrodes have been reported in the literature to enhance performance of the all-vanadium redox flow battery (RFB). An increase in carbon-oxygen functional groups has been correlated with an increase in rate of electron transfer for the VO2+/VO2
+ redox reaction and thus, enhanced performance of the all-vanadium RFB. It is proposed that surface oxide groups act as electron transfer mediators by providing reaction or adsorption sites. Thus far, treatments reported in the literature are difficult to compare, as the evaluation of each treatment varies. The use of carbon fiber ultramicroelectrodes, prepared from treated felts, can be used as a definitive basis for comparing treatments and investigating the true effect of surface alterations. Reaction kinetics of the VO2+/VO2
+ reaction can then be calculated and compared across treatments.
First, fabrication and sample mounting methods for the carbon fibers were verified by comparison to platinum ultramicroelectrodes. Then the role of the surface structure of carbon felts for the aqueous all-vanadium redox flow battery (RFB) was investigated. The graphite felt had undergone thermal, chemical, or electrochemical treatments in order to alter surface structure. The structure and composition of the felts was analyzed using x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Electrochemical performance was evaluated using cyclic voltammetry (CV), pulse voltammetry (PV), and electrochemical impedance spectroscopy (EIS). Thermally treated felts (300oC for 30hrs in air) exhibited a loss of surface functional groups, but an increase in double layer capacitance attributed to an increase in the active surface area (9.9 times that of untreated). This suggests that available surface area plays a larger role than the specific functional groups on the surface of the carbon electrodes in increasing the electrokinetics of the VO2+/VO2
+ redox reaction.
A Generalized 3D Multiphysics Model for Li-Ion Intercalation Batteries
Authors: Allu Srikanth , Pannala Sreekanth , Nanda Jagjit , Simunovic Srdjan , Turner John A 
Published: February 2020

We present the computational implementation and results of a unified formulation across the electrode-electrolyte-electrode system. This formulation utilizes a rigorous volume averaging approach typical of multiphase formulation1, 2 and recently extended to supercapacitors3. Unlike previously used methods for Lithium ion batteries based on a segregated formulation4, 5 with intermediate boundaries, by having a unified, single-domain approach, complex geometries are naturally incorporated with the numerical algorithms guaranteeing stability and convergence. The same formulation also applies to 1D, 2D and 3D geometries irrespective of the complexities associated with dimensionality as well as with electrode/electrolyte spatial arrangements. In addition, the formulation accounts for any spatio-temporal variation of the different properties such as electrode/void volume fractions and anisotropic conductivities. This generality will aid in upscaling of local material properties directly into the system-level model. The resulting governing equations are solved using finite element techniques. The modeling results are validated for standard Li-ion cells and compared against the cell level performance (see Fig. 1 for sample results). Furthermore, we conduct an investigation of the effect of spatial variability of the void volume fraction and anisotropy on the performance of multidimensional cell configurations. We analyze the cell level performance and relate it to the detailed spatio-temporal variations of charge and discharge behavior in the electrodes. Finally, we present the coupling of the electrochemical, electrical, thermal, and mechanical processes inherent to cell performance.

References:

1. A. Prosperetti, in Computational Methods for Multiphase Flow, edited by A. Prosperetti and G. Tryggvason (Cambridge University Press, Cambridge, 2007).
2. C. Y. Wang, W. B. Gu and B. Y. Liaw, J. Electrochem. Soc. 145 (10), 3407-3417 (1998).
3. S. Allu, B. Velamur Asokan, W. A. Shelton, B. Philip and S. Pannala, Journal of Power Sources 256 (0), 369-382 (2014).
4. P. Arora, M. Doyle and R. E. White, J. Electrochem. Soc. 146 (10), 3543-3553 (1999).
5. M. Doyle, T. F. Fuller and J. Newman, J. Electrochem. Soc. 140 (6), 1526-1533 (1993).
Atomic Layer Deposited Platinum Electrocatalysts on Chemically Functionalized Graphene
Authors: An Jihwan , Diankov Georgi , Park Joonsuk , Ercius Peter , Goldhaber-Gordon David , Prinz Fritz B. 
Published: February 2020

Electrocatalysts play important roles in the performance of electrochemical energy conversion devices such as fuel cells and photoelectrochemical cells. Graphene is a promising candidate for the backbone structure for electrocatalysts due to its large surface area (theoretical value of 2630 m2/g) and good electrical conductivity. Catalyst particles, e.g., Pt nanoparticles, can be integrated with graphene via wet-process route, physical vapor deposition, or chemical vapor deposition. Catalyst-graphene composite materials synthesized via these routes, however, often suffer from low chemical/mechanical stabilities, low particle density, or non-uniform coverage [1,2].
Atomic layer deposition (ALD), which is a modified chemical vapor deposition (CVD) method, is capable of decorating dense nanoparticles chemically bonded to 3-dimensional substrates in a uniform manner. In ALD, the substrate is exposed to the alternate pulses of precursor molecules, and coated with nanoparticles or conformal thin film depending on the cycle numbers. Nevertheless, the integration of graphene with ALD catalyst particles, e.g. Pt, has been challenging because the basal plane of the pristine graphene is chemically inert due to strongly sp2-bonded carbon atoms where the nucleation cannot readily occur [3].
To this end, we present a chemical functionalization method of graphenes for the subsequent ALD platinum nucleation. We show that the low-power hydrogen plasma treatment hydrogenates the basal plane of graphene and significantly increases the chemical reactivity of the basal plane, facilitating the nucleation of the Pt nanoparticles by ALD. We systematically study the dependence of the particle density and the areal coverage on the graphene thickness and on the hydrogenation duration. While the areal coverage of Pt nanoparticles on the basal plane of the pristine graphene is negligible after 100 cycles of ALD Pt (<5 %), that of the few layer graphene hydrogenated for 2 mins hugely increases to > 80 %.
We also investigate the individual particle shape, facets, and the interface between the particle and the graphene in atomic scale using probe-corrected scanning TEM (TEAM1). We show that the ALD Pt particle has epitaxially grown on the graphene with a large density of high-index facets, which makes it a promising candidate for mechanically and chemically stable electrocatalyst with high catalytic activity.

Acknowledgment

We thank Precourt Institute of Energy at Stanford university for financial support.

References

[1] E. J. Yoo, et al., Nano Lett. 9(6), pp. 2255-2259 (2009)
[2] B. Seger and P. V. Kamat, J. Phys. Chem. C 113(19), pp. 7990-7995 (2009)
[3] S. Sun, et al., Sci. Rep. 3, p. 1775 (2013)
Pattern Recognition of Dopamine, Epinephrine, Norepinephrine, Serotonin, Acethylcholine, GABA, and Glutamate in Biological Samples Using Stochastic Sensing
Authors: Stefan-van Staden Raluca Ioana , Moldoveanu Iuliana , VAN Staden Jacobus Frederick 
Published: February 2020

Pattern recognition is essential in chemical analysis of biological fluids. Reliable and sensitive methods for neurotransmitters analysis are needed.
Therefore, we developed for pattern recognition of neurotransmitters dopamine, epinephrine, norepinephrine, serotonin, acethylcholine, GABA, and glutamate a method based on stochastic sensing. Microsensors based on diamond paste modified with 5,10,15,20-tetraphenyl-21H,23H-porphyrine, hemin and protoporphyrin IX in stochastic were designed and characterized.
The proposed method can perform pattern recognition of the seven neurotransmitters on biological fluids at a lower determination level than chromatographic methods. The pattern recognition showed high reliability (RSD<1% for more than 6 months) for the simultaneous determination of the seven neurotransmitters in whole blood, cerebrospinal liquid, urine, zebra fish and snails.
Accordingly with the statistic evaluation of the results at 99.00% confidence level, the proposed sensors can be used for pattern recognition and quantification of neurotransmitters with high reliability. The best stochastic microsensor was the one based on diamond paste modified with protoporphyrin IX.
Acknowledgements The present work was supported by the European Commission through the DENAMIC project (Contract-No. 282957) and by UEFISCDI, Romania Contract-no. 186/23.10.2012.
Post-CMOS Integration of MEMS Inertial Sensors Using Oxidized Porous Silicon Technique
Authors: Ge Daohan , Ren Naifei 
Published: February 2020

At present, MEMS inertial sensor technology has an exhaustive range of applications in the field of mass-produced commercial products, such as smart phones, PDAs, automobiles, and pedometers, which cause a strong demand for small, robust, low-cost and CMOS- integrated inertial sensors. DRIE process has been widely used in the post-CMOS approach to create high aspect ratio structures [1], but the high expense and long consuming time are usually unacceptable for the mass manufacturing. In addition, during the ion beam bombardment, CMOS structures inevitably suffers from a certain amount of damages which might reduce the device performance [2].
Here we demonstrate a low-cost and CMOS compatible production method to fabricate CMOS-MEMS inetial sensors. A thick oxidized prous silicon (OPS) layer is selectively grown on the silicon substate before the standard CMOS processes for dielectric isolation and thermal isolation. The OPS techique has a substantial cost advantage over DRIE techniqe and can produce very thick layers without severe stress problems.
Lowly-doped p-type wafers (20-40 Ωcm, 500 μm-thick, [100] -oriented and polished) were used in our experiments. The whole process includes three main steps: formation of OPS layers, CMOS sturctures fabrication, and the MEMS structures fabrication.
To create thick porous silicon layer, ohmic contact was achieved by sputtering an 800 nm-thick Al film on the backside of samples. The electrolytes used for anodization contained 48 wt.% aqueous HF and DMF. Galvanostatic current densities of 500 mAcm-2 were applied from an Agilent power source with a tolerance up to 60 V. Macropore arrays with depth of about 48 μm were obtained, followed by an optimized oxidation process to form OPS layers. After that, standard CMOS process steps were used to produce electronic components. Finally, the MEMS structures are completely built on top of the finished CMOS substrate by partely removing the OPS layers, leaving the CMOS layers unthouched.
Figure 1 show SEM pictures of the cantilever beam-mass structure (Figure 1a) and comb structure (Figure 1b) released by removing the OPS layer. Figure 1c shows the MEMS inertial stuctures and CMOS electronic components obtained on the same chip. This represents an effective method to integrate MEMS sensors with electronic circuits.

References

[1] E. H. Roderick, R. H. Williams, Metal-Semiconductor Contacts, 2nded., Oxford Science, New York (1987).
[2] J.Chae, H. Kulah, K. Najafi, J. Micromech. Microeng., 15 (2005) 336.