bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Design and Development of Novel Electrolytes for Batteries and Supercapacitors
Authors: Wieczorek Wladyslaw
Published: May 2020

Electrolytes are often forgotten parts of batteries and super capacitors compared to numerous review papers and textbooks describing properties of electrode materials. The intention of the present work is to fill the gap and bring electrolytes to the attention of the scientists working in the field of electrochemical energy conversion and storage devices. New challenges appearing on the nowadays battery and super caps market force researchers to design novel electrolytes often baring features not found in up to date studied systems. These challenges are aimed to be addresses and discussed. In the present work three types of electrolytes for application in modern batteries or super caps will be presented and discussed.

Strategy on design of new Huckel type anions for electrolyte salts is presented in the context given by the review of legacy and state-of-the-art systems. Synthesis, conditions for handling, stability and electrochemical parameters of salts used or with a potential for use in lithium-ion cells are described. Effect of solvent mixtures, selection strategy of salts and solvents for battery mixtures for maximization of chosen parameters or for given application is explained.

We are going to show how crystallographic studies allow for a better understanding of electrochemical properties of Huckel type salts. Comprehensive structure analysis of crystalline materials reveals valuable information about coordination ability of anions and provides the basis to develop the model of poly (ethylene oxide) electrolytes and liquid systems. Results revealing new aggregation modes at high concentrations of lithium salts involving releasing cations by self-assembly of anionic sub network will be presented.The discovering and understanding the phenomena related to the organization of such systems in the solid state is crucial for the elaboration of novel electrolytes and gives information about cation and anion coordination in electrolytes.

Also we are going to present novel hybrid polymeric electrolytes with unmodified and surface modified fillers based on silica, alumina and titania of different grain size. Special emphasize will be put on proper choice of the filler leading to preparation of composite system with enhance conductivities and lithium cation transference number compared to unmodified polymeric electrolytes.

At the end we are going to discuss properties of several proton conducting gel polymeric electrolytes with various solvent ratios, to be used as electrolytes in super capacitor applications. The influence of the gel composition on the ionic conductivity, temperature behavior and electrochemical properties has been studied in a large temperature range (-40 to 80 °C).

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Spectroelectrochemical Study of Organic-Inorganic Hybrid Nano-Molecular Clusters Exhibiting Voltage-Gated Fluorescence Switching and Electrochromism.
Authors: Madugula Dronareddy , Wang Teng Wei , Clark Madison , Lee Mark W
Published: May 2020

Polyhedral boranes especially the twelve vertex closo-dodecaborate and ten vertex closo-decaborate anions exhibit remarkably high thermal stability and resistance to oxidative degradation. Such high stability is attributed to the extensive delocalization of their framework bonding electrons, giving rise to three dimensional aromaticity. The substitution chemistry of polyhedral boron chemistry using aromatic ligands was previously limited in scope. However, we recently reported new and extensive polysubstitution chemistry for these ions. The structural characterization of these products revealed that up to ten of B-H vertices may be replaced with phenyl, substituted phenyl, or polycyclic aromatic hydrocarbons as ligands through the formation of stable boron-carbon bonds. The resulting organic-inorganic hybrid nano-molecular ions are pseudospherical whose diameters range between 1.3 – 3.5 nanometers depending on the ligands involved. These polyarylborane clusters are found to exhibit interesting electronic and spectroscopic properties, including high solution-phase fluorescence quantum yields, high molar absorptivities, and extraordinarily large stoke shifts. Furthermore, the fluorescence emission, excitation and absorption spectra for most of these products change reversibly upon applying product-specific electrochemical potentials, thus resulting in redox-controlled fluorescence switching and electrochromism. The properties of each polyarylborane depend upon the composition and the structure of the bound ligands, and these may be tailored through chemical modification of the surface. Our study suggest that these new nanomaterials may have the potential for applications in biomedical imaging and sensor development. This presentation will focus on the details of syntheses, structural characterization, electrochemical and spectroelectrochemical properties of polyarylboranes.
Self-Organizing Anodization in Pure Molten Ortho-Phosphoric Acid: Nanoporous Niobium Oxide Layers
Authors: Altomare Marco , Cha Gihoon , Schmuki Patrik
Published: May 2020

The anodic oxidation of niobium[1–4] is investigated in an electrolyte composed of pure, molten ortho-phosphoric acid, i.e. o-H3PO4.[5–7] In a range of applied potential of 2.5-60 V and for temperatures of 60-110°C, porous niobium oxide layers can be formed.

Pore ordering and layer morphology depend on the anodization voltage, time and temperature.

At 100°C and 5 V, vertically-oriented, defined amorphous nanochannels grow with an average diameter of 6-8 nm. Higher voltages (10-20 V) lead to a lower pore ordering and to a less defined morphology that resembles a “fish bone” structure. Interestingly, at 40-60 V and after a sufficiently long anodization time (≥ 30 min), we observe the formation of a partially crystalline Nb2O5 hierarchical structure. Such structure shows a bimodal pore size distribution, with some 100 nm wide main pores that branch out into ~ 10 nm sized nanochannels.

We propose that high voltages (> 40 V) cause significant heating at the oxide/metal interface and a consequent partial crystallization of the anodic oxide. The main pore walls, partially crystalline and hence more stable in the anodizing environment, result from a gradual dissolution of the side nanochannels.

[1] Q. Lu, T. Hashimoto, P. Skeldon, G. E. Thompson, H. Habazaki, K. Shimizu, Electrochem. Solid-State Lett.
2005, 8, B17–B20.

[2] I. Sieber, H. Hildebrand, A. Friedrich, P. Schmuki, Electrochem. commun.
2005, 7, 97–100.

[3] J. Choi, J. H. Lim, S. C. Lee, J. H. Chang, K. J. Kim, M. A. Cho, Electrochim. Acta
2006, 51, 5502–5507.

[4] W. Wei, K. Lee, S. Shaw, P. Schmuki, Chem. Commun.
2012, 48, 4244.

[5] M. Altomare, O. Pfoch, A. Tighineanu, R. Kirchgeorg, K. Lee, E. Selli, P. Schmuki, J. Am. Chem. Soc.
2015, 137, 5646–5649.

[6] K. K. Upadhyay, M. Altomare, S. Eugénio, P. Schmuki, T. M. Silva, M. F. Montemor, Electrochim. Acta
2017, 232, 192–201.

[7] K. K. Upadhyay, G. Cha, H. Hildebrand, P. Schmuki, T. M. Silva, M. F. Montemor, M. Altomare, Electrochim. Acta
2018, 281, 725–737.
Application of a Holed Cathode and Anode Preparedwith a Picosecond Pulsed Laser to Lithium Ion Battery (2)~ Analysis of the Structure of Holed Cathode Layers ~
Authors: Watanabe Tatsuya , Gunji Takao , Tsuda Takashi , Ando Fuma , Ando Nobuo , Nakamura Susumu , Hayashi Narumi , Soma Naohiko , Matsumoto Futoshi
Published: May 2020

The degradation of charging/discharging capacities in the rate-performance test of lithium iron phosphate (LFP) cathodes with different loading amounts of an active material on both sides of a current collector (i.e., “unbalanced” LFP/LFP cathodes) in a laminated cell (typically composed of anode/separator/unbalanced cathodes/separator/anode) was not observed actually at low C-rates (e.g., 0.1 C). However, the rate-performance data obtained at high C-rates (e.g., > 5 C) indicated that the imbalance of the loading amounts of an active cathode material on both sides of an Al current collector causes a significant capacity degradation. We have found that it is possible to prevent the capacity degradation observed at high C-rates by holing the unbalanced LFP/LFP cathodes in a micrometer-sized grid-patterned way (the percentages of the holed area are typically several %) using a pico-second pulsed laser: The non-holed unbalanced LFP/LFP cathodes exhibited a considerable capacity degradation at C-rates which are, for example, larger than 5C, while the holed ones showed no degradation in capacity even at high C-rates (e.g., 5-20 C). Forming micrometer-sized grid-patterned holes in the LFP/LFP cathodes leads to an improved capacity and high-rate performance of their charging/discharging processes.

Figure 1
Studies on Electrochemical Performances of CZTS Anode for Lithium-Ion Batteries at Low-Temperature
Authors: Hidaru Zeru Syum , Venugopal Boya , Sabbah Amr , Reta Tadesse Billo , Wu Heng-Liang , Chen Li-Chyong , Chen Kuei-Hsien
Published: May 2020

Lithium-ion batteries (LIBs) function as power sources in various environments and the effect of temperature is one of the major factors which limits the performance and proper operations in in cold climates or high altitude areas and in space applications. Hence, the poor charge/discharge rate and short lifetime of LIBs in low-temperature areas have restricted its application for electric vehicle (EV) or a hybrid EV. In this work, copper zinc tin sulfide (CZTS) thin-film anode materials with different mixtures of electrolytes has been prepared to study the electrochemical performance at low-temperature environments. The CZTS anode, prepared from EC/DEC/DMC electrolyte has demonstrated higher efficiency and reversible capacity at -10 oC as compared to the binary electrolyte obtained from EC/DEC electrolyte. The performance of the electrolyte at different temperature ranges and the corresponding electrochemical performance of CZTS electrode is systematically analyzed. The Kinetics and surface morphology of the as-prepared CZTS anode has been analyzed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and Scanning electron microscope (SEM) respectively.

As compared to the room temperature capacity, the CZTS has demonstrated outstanding capacity retention around 55.3 % at -10 oC in the ternary solvent electrolyte mixtures after 100 cycles at 500 mA/g current density. However, in the binary EC-DEC based electrode, a rapid capacity degradation with a capacity retention of only around 27.2 % of the room temperature capacity has been observed at the same experimental conditions. This method could be an alternative approach to study the effect of electrolyte and the performance of the anode materials in the design of thin-film micro-batteries for next-generation sub-zero temperature applications. The detail characterization and experimental results with the future perspective of this study will be discussed here.
Electrochemical Self-Assembly of CuSCN/4-Cyano-4’-(N’-Methyl)Stilbazolium Hybrid Thin Films
Authors: Suzuki Toru , Tsuda Yuki , Nakamura Tensho , Uda Kyota , Yamakado Ryohei , Okada Shuji , Yoshida Tsukasa
Published: May 2020

Electrochemically self-assembled (ESA) CuSCN/4-(N,N-dimethylamino)-4’-(N’-methyl)stilbazolium (DAS) hybrid thin film was found to exhibit concerted photoluminescent (PL) property based on energy transfer from CuSCN to DAS [1]. The amount of co-precipitated DAS (P
DAS) during ESA linearly increased on increasing DAS concentration (C
DAS) in the bath but changes its slope due to switching of dye loading mechanism from diffusion limited to surface reaction limited [2]. The full analysis revealed the switching border to be dependent on the ratio between the concentration of CuSCN precursor complex, [Cu(SCN)]+ (C
comp), and C
DAS as C
comp/C
DAS = ca. 31 [3]. When the dye loading operates as surface reaction limited, phase separation of CuSCN and DAS in nano-scale occurs to exhibit efficient PL. Thus, finding an alternative chromophore with higher or lower affinity with CuSCN than DAS should result in shifting of the switching border with smaller or larger C
comp/C
dye than the above indicated value for DAS. In this study, we employed 4-cyano-4’-(N’-methyl)stilbazolium (CNS) for ESA with CuSCN. CNS has a strong dipole moment due to the presence of strongly electron withdrawing cyano group and thus is expected to exhibit a higher affinity to CuSCN than DAS.

CuSCN/CNS hybrid thin films were obtained by cathodic electrolysis with various C
CNS while fixing C
comp = 2.5 mM. P
CNS linearly increased upon increase of C
CNS and changes its slope at around 200 μM, far larger than the switching point observed for DAS (around 60 μM). The steep slope for the low C
CNS range should be determined by the diffusion of CNS to yield its diffusion coefficient D
CNS = 1.49×10-6 cm2 s-1, slightly larger than that found for DAS (D
DAS = 1.25×10-6 cm2 s-1). On the other hand, about 3 times larger P
CNS for given dye concentrations and steeper slope of surface reaction limited regime for CNS than those found for DAS indicate higher adsorption stability of CNS than DAS to CuSCN surface. Soaking the CuSCN/CNS hybrid thin films electrodeposited at C
CNS = 60 and 800 μM to represent the dye loading as diffusion and surface reaction limited, respetively, into dimethylacetamide resulted in partial and total extraction of CNS to reveal entrapment and phase-separation of CNS, just like the case of CuSCN/DAS. The maximum P
CNS appears to be saturated when C
CNS > 800 μM for CNS aggregate to occupy close to 30% of the total film volume.

The present results already nicely support the validity of the switching of ESA mechanism, being common for both DAS and CNS. Smaller C
comp/C
CNS for the switching border and larger stability constant for surface complex formation are expected for CNS than DAS from full analysis.

[1] K. Uda et al., ACS Omega, 4, 4056-4062 (2019).

[2] Y. Tsuda et al., Monatsh. Chem., 148, 845 (2017).

[3] Y. Tsuda et al., J. Electrochem. Soc., 166, B3096-B3102 (2019).

Figure 1
Confirmation of Peg Surface Αcyclodextrin Surface Mechanism
Authors: Roberge Emma , Panahi Zahra , Halpern Jeffrey M
Published: May 2020

αCyclodextrin (CD) is a unique molecule because of its hydrophobic interior cavity and hydrophilic exterior. This interior cavity can create inclusion complexes with a variety of hydrophobic guest molecules, including resveratrol, a hydrophobic molecule naturally found in red wine and grapes. Our specific surface sensing paradigm, CD attaches temporarily to surface bound polyethyl glycol (PEG), and releases when exposed to our model analyte, resveratrol. αCD-PEG system is a reusable hydrophobic molecule sensor, so understanding the modification mechanism behind its behavior is crucial to the optimization of the sensor. EIS analysis of this system implies removal of physioadsorbed PEG from the surface when first exposed to CD, leaving only thiol-bonded PEG to gold surface and αCD attached to PEG. This theory implies variable surface coverage, and further analysis is needed for optimal reusability.

Within a flow cell, eQCM, setup, αCyclodextrin-PEG system was modified onto a gold electrode using thiol-PEG. A decrease in frequency (proportional to an increase in mass) was observed upon PEG attachment. After this modification, αCD was introduced to the system and attached to the PEG, which resulted in a decrease in mass indicated by the removal of physiosorbed PEG. After this initial decrease in mass, reversibility is achieved between resveratrol measurements and CD reloading. The supported data supports the development of a PEG:CD reusable sensor paradigm.

Acknowledgements: The authors would like to acknowledge the financial support from NIH (P20 GM113131) and the Hamel Center of Undergraduate Research at the University of New Hampshire. The authors also would like to acknowledge the assistance of Dr. Halpern’s laboratory.
The Additional Effect of Transition Metals (Cu, Zn, Sn and Ag) in Palladium Electrocatalyst for CO2 Reduction Reaction
Authors: Ochiai Hiroya , Ohira Takahiro , Matsumoto Futoshi , Gunji Takao
Published: May 2020

It is important to investigate the electrochemical reduction reaction of CO2 on the catalytic selectivity dependence the materials because it might be guideline to create a co-catalyst of photocatalytic CO2 reduction. Widely studied electrocatalysts for electrochemical CO2 reduction are precious metals, such as Pd, Ag, and Au. It is known that precious metals can efficiently reduce the CO2 to carbon monoxide (CO) or formate (HCOO-). In particular, Pd nano-particles (Pd NPs) was proved as a unique electrocatalyst for CO2 reduction. HCOO- and CO generation for electrochemical reduction of CO2 on Pd NPs can be observed at low and high potential region, respectively. It should be believed that high selectivity towards CO formation can be realized by a formation of bimetallic compounds with transition metals in Pd structure.
Microstructure-Electrochemical Behaviour Correlation for Nico-GO and Nico-Mwcnts Composite Coatings
Authors: Arora Sweety , Srivastava Chandan
Published: May 2020

NiCo coatings are widely used in sensors, actuators and as protective coatings. Recent studies have shown that addition of foreign particles like Al2O3, SiC and TiO2 promotes grain randomization and refinement resulting in improved corrosion resistance performance. In the present work, NiCo coating containing varying amount of graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) were electrodeposited over mild steel substrate. Microstructure and corrosion behavior of these composite coatings were then studied as a function of the volume fraction of the secondary additives. NiCo-GO & NiCo-CNT composite coating were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) for phase identification, morphology and composition respectively. Potentiodynamic polarization studies and electrochemical impedance spectroscopy (EIS) studies in 3.5 wt. % NaCl solution revealed that the corrosion behavior of the coatings was very sensitive to the concentration of GO/ MWCNTs in the coating matrix. With continuous increase in the amount of GO/CNT in the coatings, the corrosion resistance first increased followed by a decrease, indicating possibility of an optimum with respect to the amount of the additives for achieving high corrosion resistance performance. On analyzing the electrolytic bath solution, we observed that nickel ions (Ni+2) showed preferential deposition onto the graphene oxide sheets resulting in a compositional heterogeneity near and far from the graphene-metal interface in the electrodeposited coating microstructure. This compositional segregation led to a change in the relative abundance of low angle and high angle boundaries in the coating microstructure. Electron backscattered diffraction (EBSD) technique was used to study the type of grain boundaries, strain in the grain and average grain size (area) of the samples (prepared using focused ion beam FIB). The data revealed that the samples exhibiting maximum corrosion resistance (optimum CNT/ GO concentrations) also had the highest fraction of low angle grain boundaries (LAGBs) with no additional strain in the matrix. Further increase in GO concentration resulted in more grains with high misorientation angle. In case of CNTs addition, the coatings were found to be hydrophobic in nature with a grain growth along low energy (111) direction.

Figure 1
Material Modification of Copper Hexacyanoferrates As Cathode Material for Aqueous Sodium Ion Batteries
Authors: Pan Tsung Yu , Haider Ali , Chen Han-Yi
Published: May 2020

Aqueous sodium ion battery (ASIB) is gaining more attention with the growing concern in safety and environmental issues. However, the potential window of ASIB is limited to the decomposition voltage of water. Recently, the potential window of aqueous electrolyte has been reported that it can be extended in high-concentration electrolytes. Since then, researchers are dedicating to finding cathode materials with higher discharging potential which can increase the energy density of aqueous batteries. In this study, we demonstrate a new concept in cathode material design to reach an ultra-high rate capability by modifying the side group of a Prussian blue analogue, copper hexacyanoferrates (CuHCF). The modified cathode material was carefully analyzed by ex-situ XRD measurements, X-ray photoelectron spectroscopy, cyclic voltammetry (CV), and charge-discharge measurement to reveal their electrochemical performances. The diffusivity was also calculated by potentiostatic intermittent titration technique test and Randles-Sevcik equation.

The results showed a great rate capacity for more than 80% from 1 C to 20 C accompanied with an outstanding cycle stability (~ 100% after 1000 cycle at 20 C). The high discharge plateau at about 0.7 V (vs Ag/AgCl) indicates that this material is promising in high-energy ASIB applications. This Prussian blue analogue cathode material is further tested in a full cell system with NaTi2(PO4)3 as anode material. This new concept may shed light on the field of increasing cycle stability and rate capability of Prussian blue analogues.
Charge Carrier Transport in a Polymeric Semiconductor: Poly(3-hexylthiophene-2,5-diyl) (P3HT)
Authors: Gao Zhaojing , Yelon Arthur , Santato Clara
Published: May 2020

Organic semiconductors are now widely employed in electronic and optoelectronic devices due to their solution processability and compatibility with flexible substrates. 1 The Meyer Neldel (MN) Rule or isokinetic (IK) law means that a set of comparable samples exhibit kinetic behavior independent of activation energy at an IK or MN temperature.2 It is obeyed by the electron or hole mobility, µ, in many organic semiconductors, including pentacene3, fullerene4, N-Alkyl Perylene Diimides,5 etc. The existence of MNR is still not widely known. Further, despite considerable evidence in its favor, the multi-excitation entropy (MEE) model of its origin is still frequently contested. We fabricated organic field effect transistors (FETs) based on regioregular poly(3-hexylthiophene-2,5-diyl) (RR P3HT) of three different values of molecular weight, MW, and studied the dependence of the mobility, µ, upon the gate bias, Vg
, and temperature, T. For all values of MW, we found that in the range 200 to 290 K (low T), the µ of the FET carriers exhibits an exponential dependence upon 1/T for different Vg
, with an MN temperature about 290K. Between this temperature and 350K (high T), µ increases more rapidly than it did below, and is independent of Vg
. We believe that, in the low T regime, the polaronic carriers hop along the polymer backbone chain. We attribute the high temperature behavior to the alpha relaxation of the polymers, that is to the movement of the backbone chains. We believe that in this regime, the polaronic carriers move with the mobile chains. We have also observed the effect of source-drain voltage upon µ.

Reference

1. F. Cicoira and C. Santato, Organic Electronics: Emerging Concepts and Technology, Wiley-VCH Verlag GmbH & Co. KGaA, 2013, Germany.

2. A. Yelon, et al., Multi-excitation entropy: its role in thermodynamics and kinetics, Rep. Prog. Phys., 69, 1145-1194, 2006.

3. E. J. Meijer, et al., The Meyer–Neldel rule in organic thin-film transistors, Appl. Phys. Lett., 76, 3433, 2000.

4. J. C. Wang and Y. F. Chen, The Meyer–Neldel rule in fullerenes, Appl. Phys. Lett., 73, 948 1998.

5. R. J. Chesterfield, et al., Organic Thin Film Transistors Based on N-Alkyl Perylene Diimides: Charge Transport Kinetics as a Function of Gate Voltage and Temperature, J. Phys. Chem. B, 108, 19281-19292, 2004.
Electrodeposition of Inorganic Cesium Lead Mixed-Halide Perovskites
Authors: Liu Tao , Byers Joshua
Published: May 2020

Cesium-based halide perovskites have attracted tremendous interest for stable and efficient photovoltaics due to their tunable optical and electronic properties1, 2. Herein, electrodeposition and chemical conversion were combined to access inorganic cesium lead mixed-halide perovskites (CsPbX3, X = I, Br, Cl or their mixture). Their bandgap (E
g) was tuned by controlling the halide stoichiometry in the thin films, which was achieved by varying the solution composition used during chemical conversion. Measurements of the structural and (photo)electrochemical activity of the CsPbX3 thin films will be presented for studying the relationship between composition/structure and optoelectronic properties of perovskites.

1. J. Mater. Chem. C, 2019, 7, 757;

2. Adv. Sci., 2018, 5, 1800509;
Electrochemically Controlled Polymerization through the Use of Redox-Responsive Ureidopyrimidinones for Supramolecular Polymers.
Authors: Cedano Mario , Smith Diane K. , Vuong Katrina
Published: May 2020

Supramolecular polymers are constructed along weaker, non-covalent interactions such as hydrogen-bonding. Compared to conventional polymers where monomer units react to form covalent bonds, non-covalent interactions of monomer units grant these supramolecular polymers dynamic behavior. One example of these systems that utilizes non-covalent interactions to construct supramolecular polymers are the well-investigated ureidopyrimidinones, UPy. UPy’s dimerize along their 4 strong directional hydrogen bonds in non-polar organic solvents. UPy’s have been covalently linked at the ends of smaller monomer chains so as to function as chain-linkers in the construction of larger polymer structures under favorable dimerization conditions. One interest in the use of these systems in supramolecular applications is their inherent ability of self-healing. Applying heat or mechanical stress to these systems will prevent polymerization at the H-bonds. However, upon relief of these external stimuli, H-bonding resumes. In this study, the use of electron transfer as an external stimulus to perturb dimerization and affect UPy chain polymerization will be explored. In order to exemplify the aims of this study, previously studied electroactive UPy’s will be investigated as redox-responsive chain terminators with regards to linear polymer chains that are functionalized with UPy units at their terminal ends, allowing for long-chain polymerization indicated by an increase in solution viscosity. In this study, a decrease in solution viscosity should be observed once these long chain bi-functionalized UPy polymers are in the presence of redox-responsive mono-functional UPy. Upon electrochemical oxidation / reduction of the mono-functional electroactive UPy units, an increase in viscosity is expected. The weakened H-bonding of the mono-functional UPy units will prevent chain termination and long-chain polymerization between bi-functional long chain UPy’s is expected to resume.
Lithium Isotope Separation By Electrochemical Deposition and Intercalation with Electrochemical Isotope Effect in Propylene Carbonate and [BMIM][Dca] Ionic Liquid
Authors: Zhang Zongliang , Murali Arun , Sarswat Prashant , Free Michael L
Published: May 2020

Lithium isotopes have critical applications in many fields, such as the nuclear industry due to their unique physical and chemical properties. Lithium-6 (6Li) and lithium-7 (7Li) must be separated effectively in order to be utilized. As an alternative separation method to the environmentally hazardous COLEX process, the electrochemical deposition and intercalation method taking advantage of the electrochemical isotope effect and Marcus Theory was proposed for Li isotope separation. In this study, the Li isotope separation tests by electrochemical deposition and intercalation with various cathode substrates such as Cu and graphite in propylene carbonate and 1-Butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) ionic liquid were conducted. Separation factors close to 1.10 was achieved on multiple substrates. The separation effect in this system is promising for the development of an environmentally friendly and economically feasible industrial Li isotope separation process.
Monitoring of Early Diagnosis of Parkinson’s Disease Using Functionalized Conducting Polymer and Aptamer Modified Electrode
Authors: Kim Soochan , Cho Misuk
Published: May 2020

Parkinson's disease (PD) is one of the most common neurodegenerative disorders of later life. Alpha-synuclein (α-Syn) has been found to be one of the principal components of the Lewy-body that is thought to be the pathologic hallmark of PD. A highly sensitive electrochemical impedance sensor for α-Syn monitoring was fabricated using an aptamer immobilized on functionalized conducting polymers substrates: aptamer linked with poly(pyrrole-carboxylic acid)[PPy-COOH]. The conducting polymers were employed for providing high electrical conductivity and linking agents. The sensing performace was investigated in terms of sensitivity and detection range. The fabricated sensor exhibited extremely low detection limit at a 10-8 nM level. The developed α-Syn sensor could be utilized for the early diagnosis of PD.
(Invited) The Essential Role of Carbon in Battery Applications: Several Examples from Li/Na-Based Batteries
Authors: Li Xiaolin , Zhang Ji-guang , Reed David , Sprenkle Vincent
Published: May 2020

Carbon with different structures and properties is almost indispensable as active or assisting materials in battery devices. In this presentation, I will share several examples of controlling the structure and surface chemistry of carbon materials for active anode materials, surface coating layers, and conducive and/or mechanical frameworks in different kinds of battery applications. Si-based anodes for Li-ion batteries, Na-ion batteries and Li-S batteries will be discussed.
(Invited) Are Nanotube Networks the Key to High-Rate, High Capacity Lithium Ion Batteries?
Authors: Coleman Jonathan N
Published: May 2020

Increasing the energy storage capability of lithium-ion batteries necessitates maximization of their areal capacity. This requires thick electrodes performing at near-theoretical specific capacity. However, achievable electrode thicknesses are restricted by mechanical instabilities, with high-thickness performance limited by the attainable electrode conductivity. Here we show that forming a segregated network composite of carbon nanotubes with a range of lithium storage materials (for example, silicon, graphite and metal oxide particles) suppresses mechanical instabilities by toughening the composite, allowing the fabrication of high-performance electrodes with thicknesses of up to 800 μm. Such composite electrodes display conductivities up to 1 × 104 S m−1 and low charge-transfer resistances, allowing fast charge-delivery and enabling near-theoretical specific capacities, even for thick electrodes. The combination of high thickness and specific capacity leads to areal capacities of up to 45 and 30 mAh cm−2 for anodes and cathodes, respectively. Combining optimized composite anodes and cathodes yields full cells with state-of-the-art areal capacities (29 mAh cm−2) and specific/volumetric energies (480 Wh kg−1 and 1,600 Wh l−1).

However, such thick electrode might be expected to show poor rate performance. Optimisation of the combination of areal capacity and rate performance would be simplified if a simple mechanistic model linked both parameters to electrode properties. Here we demonstrate an equation which can fit capacity versus rate data, outputting three parameters which fully describe rate performance. Most important is the characteristic time associated with charge/discharge which can be linked by a second equation to physical electrode/electrolyte parameters via various rate-limiting processes. We fit these equations to ~200 data sets, deriving parameters such as diffusion coefficients or electrolyte conductivities. It is possible to show which rate-limiting processes are dominant in a given situation, facilitating rational design and cell optimisation. In addition, this model predicts the upper speed limit for lithium/sodium ion batteries, yielding a value that is consistent with the fastest electrodes in the literature. We show that this equation completely describes much experimental rate data.
Irreversible Increase in Disorder in Doped Graphene Lithium Ion Battery Anodes during First Discharge
Authors: Bagley Jacob David , Kishore Deepan , Yeh Nai-Chang
Published: May 2020

Heteroatom-doped graphene materials show high capacity as Li-ion battery anodes. However, the Li+ reduction potential in doped graphene anodes varies drastically during charging/discharging, which adversely affects battery performance. The varying reduction potential is conjectured to result from graphene sheets aggregating during electrode preparation into a disordered graphite structure, which demonstrate a similar reduction potential profile. To test this conjecture we measured the disorder during charging/discharging via in situ x-ray diffraction. We find that the doped graphene interlayer spacing irreversibly increases during the first discharge prior to solid electrolyte interphase formation, and commensurate with this phenomena we find an increase in double-layer capacitance, suggesting an increase in surface area. These results imply an increase in disorder during the first discharge, which supports the conjecture that doped graphene batteries resemble disordered graphite. However, a significant disordering occurs during the first discharge and not necessarily during electrode preparation.
Advanced 18650 Li-Ion Capacitors of Lithium Titanate and Carbon Materials
Authors: Aphirakaramwong Chalita , Phattharasupakun Nutthaphon , Sawangphruk Montree
Published: May 2020

There are remarkedly increasing demands in electronic devices including the portable electronic devices and electric vehicles (EVs). Therefore, the energy storages that can store energy efficiently with both high energy and power densities with good cyclability as display in batteries and supercapacitors are needed. The hybrid energy storages are one of the energy storage devices merging the advantages of both batteries and supercapacitors to overcome those lacking properties in each device. Thus, the lithium-ion hybrid capacitors (LICs) are introduced consisting battery-type as negative electrode and supercapacitors-type as positive electrode. There are many selections of electrode materials that can be used in the LICs such as carbonaceous materials and lithium titanate (LTO). The cell configuration was developed and fabricated in organic electrolyte since coin-cell to cylindrical cell. Herein, the 18650 configuration is introduced as hybrid energy storage consisting LTO and activated carbon as negative and positive electrodes, respectively. Moreover, the additional additives in electrolyte are also studied and investigated to improve the electrochemical performances to the hybrid capacitors.
(Invited) Heat and Solar Harvesting from Thermoelectric Carbon Nanotube Composites
Authors: Campoy-Quiles Mariano
Published: May 2020

The conversion of waste heat into electricity using solid state devices, namely thermoelectrics, based on carbon materials has experienced renewed interest in the last decade as these materials are particularly suited for large area and low-temperature operation applications since they are abundant, low-toxicity and easy to process [1].

In this presentation we will focus on our recent attempts to further extend the sustainability and range of applications of CNT based thermoelectrics. First, we will describe the use bacteria in environmentally friendly aqueous media to grow large area bacterial nanocellulose (BC) films with an embedded highly dispersed CNT network [2]. The thick films are fully bendable, can conformally wrap around heat sources and are stable above 500 K. The resulting composite films exhibit comparable thermoelectric properties to buckypapers while saving more than 90% of the carbon nanotubes. Interestingly, BC can be enzymatically decomposed, thus completely reclaiming the embedded CNTs once the generator has reached the end of its lifetime. Second, we will show our recent studies on the stability of CNT based thermoelectrics, aimed at precisely extending their operational lifetime.

Finally, we employ the low thermal conductivities of these composites, granted by the phonon stack-electron tunnel behavior [1], to demonstrate their use as solar thermoelectrics, i.e. materials that convert the energy of the absorbed sun light into heat, and then into electricity [3].

[1] Will organic thermoelectrics get hot? M. Campoy-Quiles, Philosophical Transactions of the Royal Society A, 377, 20180352 (2019).

[2] Farming thermoelectric paper, D. Abol-Fotouh, B. Dörling, O. Zapata-Arteaga, X. Rodríguez-Martínez, A. Gómez, J. S. Reparaz, A. Laromaine, A. Roig and M. Campoy-Quiles, Energy and Enviromental Science, 12, 716-726 (2019).

[3] Solar harvesting: a unique opportunity for organic thermoelectrics? José P. Jurado, B. Dörling, O. Zapata‐Arteaga, A. Roig, A. Mihi and M. Campoy‐Quiles, Advanced Energy Materials, 1902385 (2019). DOI: 10.1002/aenm.20190238
(Invited) Macroscopically Aligned Carbon Nanotubes for Efficient Thermophotovoltaic Energy Conversion
Authors: Doiron Chloe F , Gao Weilu , Li Xinwei , Hassan Sakib , Kono Junichiro , Naik Gururaj V
Published: May 2020

Single-walled carbon nanotubes (SWCNTs) exhibit many unique properties arising from their quantum confinement. However, the lack of a controllable large-scale alignment procedure had limited the exploration of their unique properties. Our recent work has overcome this problem by demonstrating a vacuum-filtration based technique to align SWCNTs on wafer-scale. These aligned SWCNT films exhibit many interesting optical properties such as extreme optical anisotropy or hyperbolic dispersion. Besides, aligned SWCNTs are flexible, refractory (stable up to 1900 K), inexpensive, and based on earth-abundant carbon making them an excellent refractory infrared nanophotonic material platform. Such a refractory infrared material platform is exactly what is necessary to enable efficient thermophotovoltaic energy conversion.

Thermophotovoltaics is a solid-state heat-to-electricity conversion technique. It relies upon photovoltaic conversion of thermal light emanating from a hot surface to electricity. The broadband nature of thermal light makes the thermophotovoltaic conversion inefficient. Optical resonators, filters, spectrally selective thermal emitters are a few methods proposed to increase the efficiency of thermophotovoltaics. Selective thermal emitters are very promising due to their ease of design and integration. Selective thermal emitters are hot surfaces that emit thermal radiation in a narrow spectral band above the bandgap of the photovoltaic cell. The suppression of thermal emission below the bandgap and enhancement above the bandgap are the key requirements for efficient thermophotovoltaic conversion. Generally, optical properties of materials at high temperatures limit the performance of such selective emitters and the current efficiency record is about 8%. But, the hyperbolic optical property of aligned SWCNTs together with their thermal stability make aligned SWCNTs ideal for efficient thermophotovoltaics.

Here in this work, we study the infrared optical properties of aligned SWCNTs at high temperatures (1000 K) and demonstrate spectrally selective thermal emission from plain and nano-patterned thin films. Using deep sub-wavelength sized optical cavities, we show that aligned SWCNTs exhibit hyperbolic dispersion in almost of all of infrared and enhance thermal photon density by at least 100 times. Such a large enhancement in thermal photon density leads to a large suppression of unwanted sub-bandgap thermal photons and a large enhancement of above-bandgap photons. Our analysis shows that aligned SWCNTs enable 30% or higher thermophotovoltaic efficiency when operating at 1300 K with no concentration. With near-field concentration, aligned SWCNTs can allow conversion efficiencies over 50%.
(Invited) Carbon Nanotube Electronic Ratchets
Authors: Ferguson Andrew John , Blackburn Jeffrey L.
Published: May 2020

Electronic ratchets are recently demonstrated thin-film semiconductor devices with the ability to harvest energy from high-frequency signals or electrical noise. The state-of-the-art electronic ratchets have been fabricated from doped conjugated polymers, but the device performance is limited by the low charge-carrier mobility and relatively poor electrical conductivity. Enriched semiconducting single-walled carbon nanotube (s-SWCNT) networks represent an attractive alternative to conjugated polymers, since they are easy to dope and exhibit good charge-carrier transport.

While the electronic ratchet device is based on a simple field-effect transistor architecture, it requires the generation of asymmetry within the transistor channel. In this presentation, we will outline the approaches employed to control the charge-carrier doping profile to create this asymmetry. We will subsequently discuss the performance of these carbon nanotube electronic ratchets and make a comparison with their conjugated polymer counterparts.
(Invited) Nanocarbon Catalysts for Reversible Energy Storage and Conversion Via Oxygen Electrocatalysis
Authors: Wu Gang
Published: May 2020

Energy conversion and storage via direct electrochemical oxidation and reduction processes, such as the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), can provide a clean, efficient, and economically viable means of meeting this sustainability challenge, by allowing stored renewable energy to be reliably delivered where and when it is needed. During the development of the highly demanded nonprecious metal catalysts to replace precious metals for these applications, carbon catalysts have many advantages over metal oxides, including excellent electrical conductivity, high surface area, and easy functionalization. However, most carbon-based catalysts suffer from poor activity and stability for the more challenging OER under a highly oxidative conditions. This represents one of grand challenges in energy conversion research societies.

For the first time, this work demonstrated that a new class of large-diameter tubular nanocarbon (>500 nm in diameter) catalyst is capable of catalyzing both the ORR and the OER with activity comparable to Pt and exceeding Ir, respectively, for these two reactions. Most importantly, the tube catalyst exhibited good stability upon cycling across a wide potential window (0 to 1.9 V vs RHE) in 0.1 M NaOH electrolyte. The high OER activity was verified using well-designed electrochemical tests, demonstrating that the current generated during the OER arose solely from oxygen evolution, rather than carbon oxidation. This is the first example of such excellent OER activity and durability of a nanostructured carbon-based electrocatalyst across the complete ORR-OER potential window. The newly developed carbon tubes were synthesized via a one-step template-free graphitization process using inexpensive dicyandiamide (DCDA) precursor as carbon/nitrogen source and a ternary FeCoNi alloy as a catalyst. Generation of a mixed metal catalyst, i.e., FeCoNi during the graphitization process is the key factor to yield the largest tube size for maximum electrochemically accessible surface areas, dominant graphitic nitrogen doping, and thicker tube walls, which are associated with the significantly improved activity and durability. The cost effective, easily scalable, single step and environmentally benign synthesis procedure further favors this nanocarbon’s application as a practical bifunctional electrocatalyst for the ORR and OER, with potential to advance the development and commercialization of regenerative fuel cell systems and rechargeable metal-air batteries. The use of nanostructured carbon as bifunctional ORR/OER catalysts will open up new research direction in this field and further advance the role of carbon nanomaterials in oxygen electrocatalysis for energy conversion and storage.
(Invited) Electrocatalysts for Oxygen Reduction Reaction Based on Nitrogen-Doped Carbon and Atomically-Dispersed/Nanoclustered Metal
Authors: Roh JeongHan , Liu Jing , Cho EunAe
Published: May 2020

High cost of the platinum-based catalysts for the sluggish oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cell (PEMFC) is delaying wide-spread commercialization of fuel cell electric vehicles (FCEVs). It is crucial to develop highly-active and cost-effective materials to reduce amount of platinum usage and eventually to replace the platinum-based catalysts. In this respect, nitrogen-doped carbon incorporated with atomically-dispersed metal and/or metal nanoclusters (M-N-C) has attracted tremendous attention owing to their high catalytic activity towards ORR. By atomically dispersing Pt or forming Pt nanoclusters in the nitrogen-doped carbon, utilization of Pt can be maximized, resulting in ultralow usage of Pt catalyst. Fe incorporated in the nitrogen-doped carbon (Fe-N-C) has been reported as the best candidate to attain high ORR activity among the non-precious catalysts. In applying these catalysts for PEMFC, it is still required to improve activity and durability of those M-N-C catalysts in the harsh acidic environment of PEMFC.

Herein, we present Pt-N-C and Fe-N-C as highly-active ORR catalysts prepared through a facile method. To enhance ORR activity of those M-N-C catalysts, a hetero-atom is doped into the M-N-C catalyst. In addition, effects of formation of metal nanoclusters on the ORR activity are investigated with respect to the size of the nanoclusters. DFT calculation study explores active sites for the ORR in M-N-C catalysts by examining the oxygen adsorption energy of reaction intermediates towards benefiting ORR.
Graphene-Interface with Electrogenic Bacterial Membrane: Electron Transport and Energetics
Authors: Cotts Sheldon , Keisham Bijentimala , Berry Vikas
Published: May 2020

A synergistic, nanoscale electrical-interface with the membranes of exoelectrogenic microbes will have transformative impact on biological cell based electronic-devices. In this presentation, we will report a conformal graphenic interface on biocatalytic Geobacter sulfurreducens membrane that results in quantum-capacitance induced n-doping in graphene. This further enhances electron shuttling from the membrane to improve electron harvesting from the electrogenic membrane. The quantum coupling of reduced graphene oxide (rGO) with the connected protein-membrane channels leads to an additional electron density of 3.44 x 1012 cm-2 and an increase in the in-plane phonon vibration energies (G) of rGO by 5 cm-1. This n-doping enhances the electron transfer-rate from the cell membrane into the rGO improving the power density of a simplistic microbial fuel cell (MFC) by ~ 2 folds. The synergistic electron-harvesting and conformal membrane-interfacing of flexible 2D nanomaterials can lead to an evolution in the design of microbe-circuitry to power stand-alone nanodevices.

Figure 1