bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Aqueous Ammonia Sensors Using Electrochemical Stripping and Capacitive-Based Detection
Authors: Lalwani Anand Vikas , Mu Linchao , Woo Kelly , Guo Jinyu , Dong Hang , Holiday Maximillian A , Senesky Debbie G , Tarpeh William Abraham
Published: December 2020

Harmful algal blooms (HABs) and eutrophication cause billions of dollars in damages and kill a large percentage of our aquatic ecosystem. According to Bernard et al. (2014), the costs of monitoring is on the order of 1 billion USD annually and Kim (2006) reported that due to HABs, Japan lost over 1 billion dollars in aquaculture.

To monitor and predict such blooms, we need to cost-effectively and remotely monitor pollutants in our water bodies. One prominent pollutant that is a factor in causing harmful algal bloom is dissolved ammonia from agriculture and sewage treatment plants. To that end, we propose a novel and cost-effective sensing solution that can detect ammonia in water. Using selective membrane separation and electrochemical stripping, we are able to selectively isolate ammonium ions from dissolved river water and wastewater in our small-scale 3-chamber system. Through capacitive sensing, we can then measure with high sensitivity (28-bit resolution) and precision the concentration of ammonium ions present in our final chamber.

Between the first and second chamber, there is a cation exchange membrane that allows only cations to pass through. Amongst the cations, only ammonium and hydrogen ions form gases and diffuse through the gas-permeable membrane between the second and third chamber. The ammonia gas is then dissolved into the sulfuric acid present in the third chamber. The dissolved ammonium ions change the permittivity of the overall solution and this change can be measured using highly sensitive capacitive-based sensors.

Presently, we have higher than 99% selectivity in isolating ammonium ions from wastewater and river water. Our capacitive sensor has a noise floor of 0.3 femtofarad. The capacitive measurements show a linear response under 0.4 mg N/L. The combination of high selectivity and high sensitivity unlocks the ability to detect small traces of dissolved ammonia at low power draw and low costs (under $29) thus enabling the use of such methods for remote immersible ammonia sensors for environmental sensing applications along with IoT nodes.

References:

Bernard S, Kudela RM, Velo-Suárez L. Developing global capabilities for the observation and prediction of harmful algal blooms. In: Djavidnia S, Cheung V, Ott M, Seeyave S, editors. Oceans and society: blue planet. Cambridge Scholars Publishing; 2014. Chapter 6

Kim HG. Mitigation and controls of HABs. In: Granéli E, Turner JT, editors. Ecology of harmful algae. Ecological Studies. Vol. 189. Springer-Verlag; Berlin: 2006. pp. 327–338
Flow Injection Electrochemical Quartz Microbalance with ICP-OES Detection
Authors: Molina Daniel , Beyenal Haluk , Ivory Cornelius F.
Published: December 2020

The electrochemical quartz crystal microbalance (EQCM) has been previously reported in flow injection (FI) mode as a microgravimetric sensor for analytes that can be deposited onto an electrode surface through various mechanisms such as adsorption, covalent bond, or electrodeposition. Since this methodology does not provide the composition of the deposited species, it must be coupled with other analytical techniques.

In this work, a new hyphenated technique, flow injection – electrochemical quartz crystal microbalance – inductively coupled plasma optical emission spectroscopy (FI-EQCM-ICP-OES), is used to study the deposition and stripping of metallic ions under hydrodynamic conditions in a modified commercially-available EQCM flow cell with a reaction volume of 50 uL. An automatic flow injection valve (FIV) delivers a fixed volume of analyte from a sample loop to the EQCM flow cell, where the electrodeposition reaction occurs, and the current and frequency change corresponding to the mass deposited on the electrode is measured in real time. After a film of the analyte has formed it can be rapidly stripped by changing the potential of the electrode. An ICP-OES connected downstream of the EQCM provides continuous elemental analysis throughout the deposition and stripping processes. One of the advantages is the possibility of sequential deposition-stripping experiments without having to disturb the working electrode in the flow cell.

This platform was tested via flow injection of cupric sulfate samples in a sulfuric acid matrix at 200 uL/min, with cathodic electrodeposition and anodic stripping performed at different potentials. We also developed a finite element 3D model of the electrochemical flow cell in COMSOL Multiphysics®, with the simulated results in reasonable agreement to the measured current and mass deposition in the copper experiments. The image below shows the simulated [Cu+2] profile in COMSOL Multiphysics® during cathodic electrodeposition, 62 seconds after the sample enters the reaction chamber of the flow cell.

Figure 1
Novel Design of Multiple Nested Coaxial ZnO Nanotube Gas Sensors Synthesized in Porous Templates By Atomic Layer Deposition
Authors: Lin Pengtao , Zhang Kai , Baumgart Helmut -
Published: December 2020

Among the various Metal Oxide Semiconductor (MOS) gas sensor types, solid-state gas sensors based on ZnO nanostructures have been widely used due to their properties of large exciton binding energy, wide band gape of 3.37 eV, good electrical conductivity, low cost, and high mechanical stability. In this work, ZnO nanotube nanostructures were employed for gas sensing of ethanol vapor concentrations, which is aided by their high electrochemical stability, nontoxicity, and, especially, high surface-to-volume ratio. Multiple coaxial nested ZnO nanotubes were synthesized inside porous membranes and porous templates to further enhance the sensing response to ethanol vapors with vastly increased reaction surfaces.

In this study, ZnO nanotubes were synthesized by Atomic Layer Deposition (ALD) on porous Anodic Aluminum Oxide (AAO) templates with sacrificial Al2O3 layers and on porous Si membranes. The Al2O3 sacrificial layers were synthesized on porous AAO and porous Si by ALD with TMA (Al2(CH3)6) and DI water as ALD precursors. Then ZnO thin films were deposited on the surface of the sacrificial layer with precisely controlled thickness by ALD. The entire ALD procedure is considered as one ALD super cycle. More super cycles were applied to synthesize additional coaxial ZnO nanotubes. For the final removal of the sacrificial layer, Precision Ion Polishing System (PIPS) was used to first remove the top ALD surface cover. In this way, the Al2O3 sacrificial layers were exposed for Sodium Hydroxide (NaOH) etching. The objective of the Al2O3 sacrificial layers was to expose additional reactive sensing surfaces to react with the target gas by subsequent removal of these sacrificial layers. Finally, after the sacrificial layers were completely removed by wet chemical NaOH dissolution, the nested coaxial ZnO nanotube gas sensor design was fabricated with multiple sensing surfaces.

To investigate the sensing performance of ZnO nanotube gas sensors to ethanol vapor, a gas sensor testing system was developed with a sealed reaction chamber and control system with stable temperature control and accurate concentration control. The sensing performance of single ZnO nanotubes, two nested coaxial ZnO nanotubes, and three nested coaxial ZnO nanotubes to ethanol vapor were measured and analyzed under various ethanol vapor concentrations and at different operating temperatures. The ZnO nanostructures sensing results on ethanol vapor demonstrated the sensing performance was considerably enhanced due to the increased surface to volume ratio in the ZnO tube structures.
Development of Miniaturized Interdigitated Electrode Sensors and Their Application in Taste Sensing
Authors: Dudala Sohan , Srikanth Sangam , Dubey Satish Kumar , Javed Arshad , Goel Sanket
Published: December 2020

Interdigitated Electrodes (IDEs) or Interdigitated Arrays (IDAs) are frequently used in a variety of sensing mechanisms including electrochemical detection and have been subjected to extensive miniaturization in recent times. Multiple methods involving the fabrication of IDEs have been reported. However, these fabrication methods are often time consuming, multistep, skill intensive, expensive and require clean room conditions. This work reports on the fabrication and comparison of miniaturized IDEs fabricated using two inexpensive and clean room free approaches - inkjet-printing and direct laser writing (DLW) based photolithography. For inkjet-printing approach, a commercially available printed-circuit board (PCB) printer was used with a carbon ink to print the IDEs on a glass slide. For photolithography-based fabrication, a DLW system was used for the fabrication of IDEs on a copper-clad FR4 PCB board. Previously established, validated and reported models were employed for the design of IDEs. The design parameters were selected to optimize sensitivity while striking a balance with the overall size of the sensor. The application of the developed IDE sensors was demonstrated for its taste sensing capability. Sensing of five fundamental tastes, namely salty, sweet, sour, bitter, and umami, was established with electrochemical impedance spectroscopy (EIS). The chemicals which can simulate these fundamental tastes for experimental purposes were identified as sucrose (sweet), sodium chloride (salty), citric acid (sour), L-tryptophan (bitter) and guanosine monophosphate (GMP) (umami). EIS was performed on a benchtop electrochemical workstation with two electrode configurations and data was analysed in the frequency range of 1 Hz to 1 MHz. The obtained data was analyzed for different chemicals at varying concentrations and compared for changes in the response. DLW photolithography-based approach produces IDEs with excellent geometric dimensional repeatability. The IDEs produced on glass slides using Carbon ink-based printing were fabricated in under 2 minutes and cost less than US$ 0.3. Both approaches demonstrate the applications of IDEs with fairly reasonable and benchmarked taste sensing capabilities.

Figure: a) Optimised Design b) Carbon ink-based printing c) IDE printed on glass slide d) Photlithography based DLW IDE fabrication e) IDE on a copper cladded FR4 PCR board.

Figure 1
Carbon Nanotube and Organic Color Center Solvatochromism in Biomedicine
Authors: Heller Daniel A. , Antman-Passig Merav , Baker Hanan , Budhathoki-Uprety Januka , Chen Chen , Cupo Christian , Jena Prakrit Vaibhav , Kim Mijin , Langenbacher Rachel E , Shah Janki , Wang YuHuang , Williams Ryan M. , Yaari Zvi A , Zheng Ming
Published: December 2020

Optical sensor technologies for vivo use often run into difficulties when attempting to relay quantitative information. Fluorescence transmission from within tissues may be variable depending on depth and tissue heterogeneity. Modulation of the fluorescence emission band position may mitigate some of these difficulties. We developed sensors that modulate the near-infrared emission of single-walled carbon nanotubes and organic color centers (carbon nanotubes with covalent sp3 defects). We developed methods to control solvatochromic behavior to improve sensor responses, and we developed tools to observe solvatochromism within live cells and live animals. We found that nanotube solvatochromism extends to variations of local electrostatic charge, induced by adsorption/desorption of polyelectrolytes on the nanotube surface, such as proteins and nucleic acids. We also found that dielectric and charge-mediated solvatochromism can be compounded to exacerbate the response. Upon triggered desorption of a polyelectrolyte, amphiphilic molecules can adsorb to the recently-uncovered nanotube surface. This work has enabled the detection of disease biomarkers, drugs, and metabolites, and nucleic acids, including virus RNA, facilitating improvements in disease detection, drug development, and biomedical research.
(Invited) Development of a Single Walled Carbon Nanotube Sensor for Long Term Implantation and Detection in a Large Animal Model
Authors: Iverson Nicole M , Hofferber Eric M , Meier Jakob , Herrera Nicolas , Calkins Chris , Kachman Stephen D
Published: December 2020

Fluorescent sensors are frequently not used for in vivo research due to photobleaching and difficulty in signal detection. Single walled carbon nanotubes (SWNT) circumvent these issues with near infrared fluorescent emission and long term stability; yet detection of carbon nanotube sensors has never before been performed in large animal models. The ability to place and read SWNT sensors in vivo for a large animal requires specialized instrumentation and research facilities. By teaming up with large animal veterinarians and meat scientists, our lab was able to surgically place, monitor, and recover SWNT sensors from 14 sheep. We examined various SWNT platforms, implantation locations, and detection methods to determine a strategy for frequent, consistent detection of SWNT sensors that serve as an indicator of animal stress and overall health.
(Invited) Extending the Stability of Electrochemical, Aptamer-Based Sensors In Vivo
Authors: Arroyo Netz
Published: December 2020

Electrochemical aptamer-based (E-AB) sensors are a technology that enables precise measurements of specific molecular targets in the body. They have been demonstrated to support real-time therapeutic drug monitoring and feedback-controlled drug dosing in living animals. However, one drawback of E-AB sensors is the rapid degradation of their sensing interface upon continuous interrogation via, for example, voltammetry. Over time, the faradaic current from their aptamer-attached redox reporter decreases, and the currents from charging the electrical double-layer increase beyond the faradaic current, thus preventing signaling. The latter effect is due to progressive desorption of the electrode-passivating alkyl thiol monolayers employed in these sensors. This progressive degradation limits their in-vivo operational life to hours, a period too short for monitoring the vast majority of drugs in humans. Attempting to address this problem, my laboratory is investigating novel monolayer chemistries that extend the operational life of E-AB sensors without compromising their sensing performance or biocompatibility. In this presentation, I will discuss the effects that different monolayer chemistries have on E-AB sensing performance and how they extend the in-vitro operational life of E-AB sensors for days in undiluted biological fluids.
Real-Time Glucose Monitoring System Containing Enzymatic Sensor and Reference Electrodes for Application In Vivo
Authors: Ramašauskas Lukas , Ratautas Dalius
Published: December 2020

Nearly every electrochemical biosensor uses two or three electrode setup which involves sensing electrode (usually containing oxidoreductase) for a specific reaction, metal/salt reference electrode (i.e., Ag/AgCl or Hg/Hg2Cl2) for the control of the potential and, is some cases, counter electrode for the compensation of the current. This setup did not change significantly since 1962,1 when the idea of biosensors was proposed, despite having significant flaws related to metal/salt reference electrodes: they are bulky and difficult to miniaturize, leak electrolyte to the medium, lose the ability to define the electrochemical potential precisely in time, consequently, have to be updated or replaced.2 This causes significant problems then the biosensor cannot be easily replaced (e.g., implanted electronics). It is worth noting, that significant potential drifts for an in vivo tested metal/salt reference electrodes (Ag/AgCl or Hg/Hg2Cl2) were noticed as early as in 1986,3 yet little efforts were reported to solve the above-mentioned issues, despite significant advances in the development of sensor electrodes. The majority of the reported works focused on improvement and miniaturization of current technology – metal/salt electrodes.

Here we present a real-time glucose monitoring system capable of referencing its own electrochemical potential (Figure). By using sensing electrode composed of wired glucose dehydrogenase and enzymatic reference electrode composed of wired laccase we have managed to create stable and accurate electrode system which measured fluxes in concentration of glucose in a physiological range (3–8 mM). To the best of our knowledge, this is the first fully enzymatic electrode system capable to reference its own potential and avoid usage of metal/salt reference electrodes. Our designed enzymatic reference electrode is universal and we envision that it may be applied for other biosensors, thus open possibilities for the new generation of implantable devices for healthcare monitoring in vivo.

References

(1) Clark, L. C.; Lyons, C. Electrode Systems for Continuous Monitoring in Cardiovascular Surgery. Annals of the New York Academy of Sciences
1962, 102 (1), 29–45.

(2) Hashemi, P.; Walsh, P. L.; Guillot, T. S.; Gras-Najjar, J.; Takmakov, P.; Crews, F. T.; Wightman, R. M. Chronically Implanted, Nafion-Coated Ag/AgCl Reference Electrodes for Neurochemical Applications. ACS Chemical Neuroscience
2011, 2 (11), 658–666.

(3) Thompson, M.; Vandenberg, E. T. In Vivo Probes: Problems and Perspectives. Clinical Biochemistry
1986, 19 (5), 255–261.

Figure 1
The Effects of H3PO4 Treatment on Li/Mn-Rich Layered Li1.2-X[Mn0.55Ni0.15Fe0.10]O2(1-x)F2x Cathode Materials for Li-Ion Batteries
Authors: Acuna Sinjin , Kucuk Kamil , Segre Carlo U. , Timofeeva Elena V.
Published: December 2020

In this study, sol-gel synthesized Li/Mn-rich layered Li1.2-x[Mn0.55Ni0.15Fe0.10]O2(1-x)F2x was studied as an alternative to commercial NMC and LiCoO2 batteries due to greater theoretical capacity ~250 mAh g-1, increased safety, and lower-cost. Despite these advantages, MNF cathodes show experimentally lower capacity and decay, voltage fading, and poor rate capability [1]. To address these problems, the creation of a Li3PO4-coating with a H3PO4 solution treatment was investigated. Treatment has resulted in increased initial discharge capacity for the first 3 cycles at 0.1C and increased cell retention for the following 97 cycles at 0.33C compared to untreated MNF551510. As alternatives to the classic NMC and LiCoO2 arise, H3PO4 treatment can be a useful technique to enhance electrochemical performance of novel cathode materials.

Powder X-ray diffraction was used to determine the phase of the material as well as the amount of lithium carbonate contamination before and after Li3PO4-coating. Furthermore, scanning electron microscopy (SEM) was performed to analyze the effects of Li3PO4-coating on the morphology of the particle. For electrochemical analysis, galvanostatic charge-discharge cycling and cyclic voltammetry (CV) were completed.
Covalent Triazine Frameworks Incorporating Charged Polypyrrole Channels for High-Performance Lithium-Sulfur Batteries
Authors: Elabd Ahmed , Kim Jiheon , Chung Sung-Yoon , Coskun Ali , Choi Jang Wook
Published: December 2020

Covalent triazine frameworks (CTFs) have emerged as promising electrode materials for lithium-sulfur (Li-S) batteries owing to their pristine pyrdinic sites, conjugated backbone and ability to stabilize remarkable sulfur contents. Following the first synthesis of sulfur-CTFs under catalyst and solvent-free reaction conditions[1], new synthetic strategies have been extensively investigated to improve CTFs properties for Li-S batteries applications. Further upgrading for CTFs was introduced to achieve extremely high sulfur contents CTFs via employing nucleophilic aromatic substitution reaction (SNAr) between perfluoroaryl units and elemental sulfur.[2] However, the previous (SNAr) approach possessed immense sulfur conent up to 82%, it is challenging to endure high ionic and electronic conductivity with mitigation of Li-polysulfide (Li-PS) shuttling. These fatal problems limit their cycling performance at high active mass loadings. In an effort to tackle the previously mentioned problems, a new approach incorporates the integration of one-dimensional charged conducting polymers with a two-dimensional covalent triazine framework in the presence of elemental sulfur.[3] Noticeably, the addition of charged conducting polymers triggers a 3D nanochannel formation in the CTF framework with high-affinity anchoring sites towards Li-PS while achieving decent ionic and electronic conductivity. The resulting polymers showed significantly improved ionic , electronic conductivities and high sulfur loadings. Because of these remarkable properties, we are able to obtain exceptional electrochemical performance at high mass loading of 3 mg sulfur per cm2 with a specific capacity of 1275.2 mAh g−1 at 0.05C.

References:

[1] S. N. Talapaneni, T. H. Hwang, S. H. Je, O. Buyukcakir, J. W. Choi, A. Coskun, Angew. Chemie - Int. Ed.
2016, 55, 3106–3111.

[2] S. H. Je, H. J. Kim, J. Kim, J. W. Choi, A. Coskun, Adv. Funct. Mater.
2017, 27, 1–9.

[3] J. Kim, A. Elabd, S-Y. Chung, A. Coskun, J. W. Choi. Chem. Mater.
2020, under revision.
Underpotential Lithium Plating on Graphite Anodes Caused By Temperature Heterogeneity
Authors: Wang Hansen , Zhu Yangying , Cui Yi
Published: December 2020

Rechargeability and operational safety of commercial lithium (Li)-ion batteries demand further improvement. Plating of metallic Li on graphite anodes is a critical reason for Li-ion battery capacity decay and short circuit. It is generally believed that Li plating is caused by the slow kinetics of graphite intercalation, but in this paper, we demonstrate that thermodynamics also serves a crucial role. We show that a non-uniform temperature distribution within the battery can make local plating of Li above 0 V vs. Li+/Li0 (room temperature) thermodynamically favorable. This phenomenon is caused by temperature dependent shifts of the equilibrium potential of Li+/Li0. Supported by simulation results, we confirm the likelihood of this failure mechanism during commercial Li-ion battery operation, including both slow and fast charging conditions. This work furthers the understanding of non-uniform Li plating and will inspire future studies to prolong the cycling lifetime of Li-ion batteries.
Analysis of the Effect of Particle Shape on Pore Structure
Authors: Oh Hyeseong , Kim Youngmin , Jeong Kyeong-Min
Published: December 2020

Market requirements for lithium-ion batteries are gradually increasing as they expand their applications from small electronic devices to large EVs and ESSs. Various active materials, binders, and conductive materials could be used to make batteries. In manufacturing electrodes, the microstructure of each porous electrode will vary depending on the size and shape of the particles used.1 Many studies show that the microstructure of lithium-ion battery electrodes affects cell resistance, cycle life, and rate capabilities.

In this study, electrodes with various mass loading levels and composite densities were fabricated using single crystal and secondary particle NCM cathode active materials. Two major parameters of the porous electrode, porosity and tortuosity, were obtained. Mercury intrusion porosimetry was used to measure porosity. Tortuosity was obtained from Bruggeman’s relationship,2,3 using electrochemical impedance spectroscopy (EIS). We compared porosity and tortuosity values with the SEM image of each electrode. It was confirmed that the pore structure can be well maintained in the single crystal NCM based electrode due to the high stiffness of the active material.

References

Harris, Stephen J., and Peng Lu. The Journal of Physical Chemistry C 13 (2013): 6481-6492.

Landesfeind, Johannes, et al. Journal of The Electrochemical Society 7 (2016): A1373-A1387.

Bruggeman, Von DAG. Annalen der physic 7 (1935): 636-664.
Application of Spinel MgMn2-X
Al
x
O4 As Cathode for Mg Rechargeable Battery
Authors: Yokozaki Rika , Kobayashi Hiroaki , Mandai Toshihiko , Honma Itaru
Published: December 2020

【Introduction】

Lithium-ion battery (LIB) has mainly used in our life, but its high price due to Li and Co metals are crucial problem. Magnesium rechargeable battery (MRB) has been recently studied as a post LIB due to elemental abundant supply and superior theoretical volumetric energy density of magnesium. For cathode materials, spinel oxides is one of a candidate of MRB due to its high redox potential and three-dimensional diffusion paths.[1] Especially, MgMn2O4 is expected to perform high theoretical capacity because utilization of both Mn3+/Mn4+ and Mn2+/ Mn3+ redox is possible in the potential window of the common electrolyte.[2] But structural change from tetragonal to cubic occurs due to Jahn-Teller effect of Mn3+ ion during charge/discharge, which decreases reversibility. In this study, we tried to enhance reversibility of MgMn2O4 spinel by substituting Al for Mn to release its Jahn-Teller distortion, and the optimal substitution ratio and their electrochemical property were evaluated.

【Experimental】

MgMn2-xAlxO4 (x = 0, 0.1, 0.2, 0.5) were synthesized by Pechini method[3] with an annealing process of 400 ºC, 10 hour. Cathodes were prepared by mixing the obtained samples with acetylene black and polytetrafuluoroethylene at a weight ratio of 60/30/10 . Mg alloy (AZ31) was used for an anode. Galvanostatic charge/discharge profiles were obtained by using a coin cell with a 0.3 M Mg[B(HFIP)4]2/triglyme electrolyte at 25 ºC, 10 mA/g.

【Results and discussion】

According to X-ray diffraction(XRD) patterns, MgMn2-xAlxO4 (x = 0, 0.1, 0.2, 0.5) spinel were obtained and their crystallinity become lower by Al substitution. In MgMn1.5Al0.5O4, the crystal structure changed from tetragonal to cubic phase, suggesting that the Jahn-Teller effect is suppressed by the formation of the solid solution of tetragonal MgMn2O4 and cubic MgAl2O4. The Al-substituted MgMn2O4 exhibited higher discharge capacities compared with MgMn2O4 (64.0 mAh/g), and especially MgMn1.9Al0.1O4 showed the highest discharge capacity of 92.3 mAh/g. In the poster session, X-ray absorption spectroscopy (XAS) and cycle characteristics will be reported.

【Acknowledgment】

This work was supported by JST ALCA-SPRING Grant Number JPMJAL1301, Japan.

【References】

[1] S. Okamoto, T. Ichitsubo, T. Kawaguchi, Y. Kumagai, F. Oba, S. Yagi, K. Shimokawa, N. Goto, T. Doi and E. Matsubara, Adv.
Sci., 2015, 2, 1500072

[2] H. Kobayashi, K. Yamaguchi and I. Honma, RSC Adv., 2019, 9, 36434-36439.

[3] J. Yin, A. B. Brady, E. S. Takeuchi, A. C. Marschilok and K. J. Takeuchi, Chem. Commun., 2017, 53, 3665-3668.
Enhancement of Electrochemical Redox Reaction By Transition Metal Oxalates for High-Performance Lithium-Sulfur Battery
Authors: Seo Gyuwon , Kim Jin Won , Lee Jaeyoung
Published: December 2020

As the size and usage of electronics are diversified, demand for secondary batteries with higher capacity and performance is increasing. Lithium-sulfur(Li-S) battery is one of the promising next generation battery due to high theoretical capacity(1,672 mAh/g), natural abundance and environmental nontoxic compare to conventional active materials of lithium-ion batteries. However, lithium polysulfide(PS) dissolution issue which causes capacity fade inevitably must be overcome for commercialization.

In this study, we introduced first transition metal oxalates as cathode additives which have a high polar surface area to enlarge the electrocatalytic interfacial boundary enabling LiPS redox reactions to occur, by controlling the carbon and metal oxalates ratio. Furthermore, physicochemical interactions between LiPS and metal oxalates were verified by UV-vis, X-ray Photoelectron Spectroscopy and Electrochemical Analysis(Cyclic Voltammetry, Galvanostatic Intermittent Titration Technique, Electrochemical Impedance Spectroscopy). As a result, the modified cathode by the best candidate effectively decreased cell overpotential and improved the cycle stability by maximized electrochemical utilization

Figure 1
Development of Negative Electrode for Calcium Ion Battery Using Marimo Nano Carbon
Authors: Nishimura Yuichiro , Nakagawa Kiyoharu
Published: December 2020

Lithium-ion batteries (LIBs) are used in various fields due to their high energy density and high cycle characteristics. In general, graphite materials are used for the negative electrode materials for lithium-ion batteries (LIBs). However, since the amount of Li ion that can be stored in the graphite material of the negative electrode is approaching the theoretical value for LIBs, a significant increase in capacity cannot be expected.

Calcium ion batteries (CIBs) use Ca ion as charge carriers. Therefore, they can be expected to have twice the capacity of LIBs. In LIBs, charge and discharge mechanism occurs by intercalation and deintercalation of Li ion into graphite layers. However, Ca ion are poor in reactivity, intercalation and deintercalation of Ca ion do not occur in the graphite negative electrode, and charge and discharge capacity cannot be obtained. For this reason, we used Marimo Nano Carbon (MNC) as a new negative electrode material. MNC is an aggregate of carbon nano filaments (CNF). CNF has a layered structure similar to graphite and also has amazing electronic properties and many other unique properties. This CNF has coin-stacked structure in which graphene layers are stacked, and the edge surface is exposed. Hence, we expected that MNC negative electrode would react with less reactive Ca ions and indicated larger charge / discharge capacity than that of the graphite negative electrode. In this study, we evaluated MNC negative electrode performance.

For MNC synthesis, nano metal particles carried on oxidized diamond were used. Oxidized diamond has oxygen-containing functional groups arranged regularly. Thus, nano metal particles are a highly dispersed on it. Pd metal was used for carried metal. Pd metal could synthesized CNF having coin-stacked structures. Pd metal was carried on oxidized diamond by metal nano-colloidal method. C2H4 as a feedstock for CNF was used, and MNC was synthesized by the chemical vapor deposition (CVD) method.

When MNC was used as the negative electrode material, the charge and discharge capacity was larger than that of the graphite negative electrode. In addition, the intercalation of Ca ions between the graphene layers was confirmed.
(General Student Poster Session Winner - 1st Place)Feasibility of LiNbO3 Surface Coating on High-Ni Layered Cathode Materials for Lithium Ion Batteries
Authors: Kim Jong Hwa , Choi Wonchang , Park Min-Sik
Published: December 2020

Recently, lithium ion batteries (LIBs) have received great attention as a suitable power source for electric vehicles (EVs) because of its highest energy and power densities among currently available energy storage systems. For successful implementation the achievable energy density of current LIBs should be further improved to meet the industrial requirements. In this respect, the development of advanced materials is crucial for improving the energy density of LIBs. During the last decade, layered lithium transition metal oxides (e.g., LiMO2, M = transition metal) have been used as the most popular cathode materials in commercial LIBs [1]. From a structural point of view, Li+ can be reversibly inserted and extracted in the given structure based on the redox reactions of transition metals. Therefore, the choice of transition metals is crucial for determining the electrochemical properties of these cathode materials. By increasing the Ni concentration, the reversible capacity of the cathode materials can be effectively increased due to the double redox reaction of Ni2+/Ni4+. In practice, high-Ni layered cathode materials (Ni > 80%) can offer a high reversible capacity over 200 mAh g-1 [2]. As a result of increasing the Ni concentration, however, the cathode materials suffer from poor cycle performance and thermal stability mainly induced by side reactions with electrolyte and residual Li at the surface. To overcome these limitations, effective surface coatings are required to make the surface more stable and suppress undesirable side reactions [3]. Herein, we propose a surface coating with LiNbO3 onto NCM811 cathode material to minimize undesirable side reactions as well as improve the thermal stability [4]. Thanks to the high ionic conductivity and thermal resistance of LiNbO3, LiNbO3 coated NCM811 exhibit much improved cycle performance and rate capabilities even at high operating temperature of 60 oC. Moreover, we also investigate the effect of LiNbO3 crystallinity on the electrochemical properties of LiNbO3 coated NCM811. It would provide a practical guideline for the development of a highly reliable high-capacity cathode material for EV applications.

References:

[1] M. M. Thackeray, J. Electrochem. Soc. 142 (1995) 2558-2563.

[2] P. Hou, J. Yin, M. Ding, J. Huang, X. Xu, Small 13 (2017) 1701802.

[3] Z. Chen, D. Chao, J. Lin, Z. Shen, Mater. Res. Bull. 96 (2017) 491-502.

[4] M. Gellert, K. I. Gries, J. Sann, E. Pfeifer, K. Volz, B. Roling, Solid State Ion. 287 (2016) 8-12.
The Making and Baking of Coordination Polymers for Li-Ion Batteries
Authors: Shuaib Umaira , Indris Sylvio , Darma Mariyam Susana Dewi , Powell Annie K.
Published: December 2020

As demand for efficient and sustainably clean energy has thrust global research towards proficient energy storage systems (ESSs), which are capable of accommodating large capacities, portable systems that have a high energy and power density have become significantly important. The increasing need for hybrid electric vehicles, electric vehicles and portable devices with longer and more stable battery life, has boomed the applications of lithium-ion batteries considering their safety and reliability make them the most promising ESSs currently available on the mass market. However, their high energy density and limited self-discharge is hindered by the use of graphitic anodes. Transition-metal oxides (TMOs) have plenty of applications across many different fields of science; solar cells, gas sensors and the electronics industry are some areas where the progression from research to application has been extremely rapid. Manganese oxides (MnOs) are a common and commercial active material used in the electrodes of energy storage devices such as batteries, because they have a higher theoretical capacity (756 mAh g-1) compared to the conventional anode material graphite (372 mAh g-1).

Here we present both a TMO anode material as well as the corresponding cost effective porous carbon as graphite replacements for lithium-ion cells that observe stability in both the capacitance and redox potentials. Templating the battery materials from coordination polymers allows a fraction of control of the resultant materials obtained post pyrolysis. The as-synthesized MOFs and clusters have a carbon content of c.a 50% . The resultant oxide has a carbon content of ...c.a X%. BET analysis of these materials alongside the porous carbon shows surface area increasing from X to Y to Z respectfully.
Electrochemical Properties of LiNiO2 Integrated with Nanosize Li3PO4
Authors: 池田 直広 , Yabuuchi Naoaki , Aita Taira
Published: December 2020

The demand of EVs is growing in the world and further increase in energy density of lithium-ion batteries (LIBs) is required. Among positive electrode materials for LIBs, LiNiO2 and its derivatives have been considered as an alternative material to LiCO2 because of its high reversible capacity, good rate capability, and relatively low material cost.[1] Nevertheless, LiNiO2 without cobalt ions shows insufficient irreversibility especially upon charge to high voltage. In this study, nanosized Li3PO4 is integrated into LiNO2, which is synthesized by mechanical milling and post heat treatment, and is tested as a positive electrode material in Li cells. We also discuss the possibility of high-performance and Co-free electrode materials for LIBs.

A binary system of x Li3PO4 – (1 – x) LiNiO2 (x = 0, 0.03, and 0.05) with a rocksalt structure was synthesized by mechanical milling and used as a precursor. The precursor with a rocksalt structure was heated at 650 oC in oxygen, resulting in the formation of layered LiNiO2 integrated with nanosize Li3PO4 domains. Characterization of the samples was conducted by X-ray diffraction (XRD) and scanning electron microscopy (SEM). For the evaluation of electrochemical properties, composite electrodes consisting of 80 wt% active material, 10 wt% AB, and 10 wt% PVdF, were casted on aluminum foil. 1.0 M LiPF6 dissolved in ethylene carbonate (EC)/dimethyl carbonate (DMC) (3/7 by volume) solution was used as electrolyte.

XRD patterns of x Li3PO4 – (1 – x) LiNiO2 (x = 0.03 and 0.05) binary system after milling are assigned into the rocksalt structure that is a metastable phase. After heating, the crystal structure of the samples is changed into the layered phase, and a uniform distribution of Ni and P was confirmed from energy dispersive X-ray elemental mapping. This finding suggests that nanosized Li3PO4 is successfully integrated into LiNiO2. Figure 1 shows the galvanostatic charge/discharge curves of the samples cycled in the voltage range of 2.5 and 4.5 V at a rate of 10 mA g-1 in Li cells. Layered LiNiO2 without Li3PO4 (x = 0) delivers a discharge capacity of 210 mA h g-1 at initial cycle. However, capacity degradation is non-negligible upon further cycles. In contrast, the sample of x = 0.03 exhibits a slightly reduced capacity of 190 mA h g−1, but the significant improvement of cyclability is evidenced even electrochemical cycle with charge to 4.5 V. From these results, we will further discuss the impact of integration of nanosize Li3PO4 into layered LiNiO2 and the possibility of Co-free electrode materials in the future.

References

(1) Y.-K. Sun et al., ACS Energy Lett.
2, 1150, (2017).

Figure 1
Phase-Field Simulation of Li-Ion Diffusion and Stress Evolution in Cathode Materials in NCA-Type Li-Ion Batteries
Authors: Yamanaka Akinori , Endo Hajime , Nakamoto Mitsunori , Yamaguchi Kikou , Kamisaka Hideyuki , Koshitani Naoki , Endo Kazuaki , Yano Masato , Tanaka Masatomo
Published: December 2020

The crack propagation in a positive electrode of lithium (Li)-ion batteries degrades the performance of Li-ion batteries. The crack propagation is driven by the Li intercalation- and deintercalation-induced stress-field in the electrode. In order to prevent the degradation of Li-ion battery performance, it is essential to understand the Li-ion diffusion and stress evolution in the positive electrode during the charging and discharging processes. Phase-field (PF) method has been widely used as a powerful numerical simulation methodology for analyzing micro- and meso-scale phenomena including electrochemical reactions. In this study, we develop a PF model for simulating the Li-ion diffusion and stress evolution in a positive electrode in a LiNi1-x-y
Co
x
Al
y
O2 (NCA)-type Li-ion battery, which attracts attentions as a high-capacity cathode material. In the PF model, the Li-ion diffusion in the NCA electrode is treated by the Cahn-Hilliard equation which incorporates the Butler-Volmer equation. The stress evolution is analyzed based on the PF microelasticity theory. The elastic constants and lattice misfit strains of NCA electrode used in the PF model were obtained from first-principles calculation. Using the developed PF model, we investigate the Li-ion diffusion and stress evolution in a NCA second-particle, which strongly depends on the distribution and crystal orientation of primary NCA particles in the second-particle.
Effect of Alloying Elements on Pit Growth in AA7075
Authors: Sampei Yota , Muto Izumi , Sugawara Yu
Published: December 2020

AA7075 is known to a show high strength/weight ratio but suffers from localized corrosion, such as filiform corrosion, pitting, crevice corrosion, and stress corrosion cracking in Cl-containing environments. It has been proposed that Cu-containing intermetallics deteriorate the corrosion resistance and are the initiation sites of pitting. When AA7075 is immersed in an aqueous solution containing NaCl, the intermetallic compounds dissolve, and Cu-enriched particles are formed on and around the intermetallic compounds. Then, the Cu-enriched particles act as a cathode for the oxygen reduction and hydrogen generation reactions, and a strong alkali is locally generated. As a result, it is considered that the Al matrix dissolves, and local corrosion occurs. Therefore, alloy elements that suppress the cathode reaction on the Cu-enriched particles were studied.

The samples were prepared from the arc-melting of AA7075 and pure Sn. The concentration of Sn was changed from 0.1 to 5 mass%. After casting, the ingots were heated to 430°C and rolled to a thickness of 2 mm. A solution treatment was performed at 500°C for 2 h. After the heat-treatment, the sample surfaces were polished with a diamond paste down to 0.25 µm.

In order to characterize the shape and distribution of the intermetallic particles in the samples, the sample surfaces were observed with an optical microscope and SEM-EDS. The open circuit potentials of AA7075 were measured in 0.1 M NaCl adjusted to pH 6.0 for 16 h. The area exposed to the electrolyte was 10 mm × 10 mm. The measurements were performed in a naturally aerated solution, and Ag/AgCl (3.33 M KCl) was used as a reference electrode. After immersion, the sample surfaces were inspected. Anodic polarization curves of AA7075 were measured in 0.1 M NaCl adjusted to pH 6.0. The measurements were performed in the aerated solution, and the electrode area was 10 mm × 10 mm. In addition, that of pure Sn was also measured. The number of intermetallic compounds in AA7075 with 0.1 mass% Sn was low compared with AA7075. In the initial stage of immersion of AA7075 and Sn-added AA7075, the open circuit potentials were located approximately – 1.0 V and increased with time. Finally, the potential reached around – 0.7 V. The lower potential duration was prolonged by the Sn addition. After immersion, filiform-like corrosion and pitting were observed on the samples. In addition, the Al-matrix and the intermetallic compounds discolored by dissolution. The pitting potential of AA7075 and the 0.1 mass% Sn-added AA7075 alloy was -0.65 V, and no difference was observed.
First Principles Prediction of Corrosion Kinetics As a Function of Microstructural Features in Precipitation Hardened Aluminum Alloys
Authors: Li Sirui , Zhu Yakun , Taylor Christopher
Published: December 2020

In this poster, first principles density functional theory (DFT) implemented in the Vienna Ab Initio Simulation Package (VASP)1 is coupled with micro-kinetic model2 to simulate the electrochemical corrosion kinetics of some commonly identified intermetallic particles3 (IMPs) associated with precipitation hardened aluminum alloys such as AA7075. First principles DFT calculation is used to characterize the adsorption energies for the cathodic reaction intermediates on intermetallic surfaces. The species include atomic oxygen (O) and hydroxide (OH) as intermediates for the oxygen reduction reaction. We will show that when coupling the thermodynamic calculations with an appropriate micro-kinetic model, we can predict the corrosion kinetics of IMPs. One of the most desirable properties obtained from the simulated polarization curve is the corrosion potential of the IMPs. The corrosion potential can indicate the relative nobilities of IMPs with respect to the alloy matrix. Experimentally the corrosion potential of IMPs on the range of microns are measured via a micro-capillary cell technique. With the state of the art TEM, localized corrosion even down to the nm scale can be characterized4. On the simulation side, however, a method that can be directly compared to experimental data has not yet been fully realized. Attempts to estimate corrosion potentials from the surface work functions obtained by DFT calculations have been made in recent literature but the direct correlation of work function to the corrosion potential has a significant band of uncertainty associated with it. Rather than finding direct correlation, we incorporate work function into the kinetics equation as one of the input parameters. Our simulated for Al7FeCu2, one of the most commonly identified IMP in high strength aluminum alloy, is -337 mVNHE, which is in good agreement with experimental data (-307 mVNHE). We contend here that a first-principles model founded in electrode kinetics is a promising path forward for bridging first-principles simulation and experiment in corrosion science.

Reference

G. Kresse and J. Furthmüller, Comput. Mater. Sci., 6, 15–50 (1996).

H. A. Hansen, V. Viswanathan, and J. K. Nørskov, J. Phys. Chem. C, 118, 6706–6718 (2014) http://pubs.acs.org/doi/abs/10.1021/jp4100608.

N. Birbilis and R. G. Buchheit, J. Electrochem. Soc., 152, B140 (2005) http://jes.ecsdl.org/cgi/doi/10.1149/1.1869984.

Y. Zhu et al., Acta Mater., 189 (2020).
Effect of Applied Voltage on Isotope Separation Factor By Electrodialysis Using Lithium Ion Conductive Electrolyte La0.57Li0.29TiO3
Authors: Shin-mura Kiyoto , Tokuyoshi Ryoya , Sasaki Kazuya
Published: December 2020

Tritium, which is used as a fuel in a thermonuclear fusion reactor, is produced in the fusion reactor blanket by the reaction of neutrons with lithium whose 6Li-isotope-ratio is 90%. Other than the mercury amalgam method, which has a large environmental impact, no practical lithium isotope enrichment technology has been established. Electrodialysis using the lithium ion conductive electrolyte La0.57Li0.29TiO3 (LLTO) is promising, as reported to achieve high isotope enrichment [1]. In this study, we investigate the effect of applied voltage in electrodialysis on the isotope separation factor.

An anode (primary solution side) and a cathode (secondary solution side) were formed on both front and back surfaces of LLTO. One reference electrode was also formed on each surface of the LLTO. DC voltage of various magnitudes was applied between the anode and the cathode. The electrochemical impedance between the reference electrode on the primary solution side and the anode during the application of this voltage was measured by AC impedance spectroscopy. At the same time, the electrochemical impedance between each of the secondary solution side reference electrode and the cathode was also measured. The amount of transferred lithium and the isotope ratio of lithium were measured by an inductively coupled plasma mass spectrometer (ICP-MS).

The lithium isotope separation factor increased linearly with decreasing applied voltage. Here we assume the following: ① The existence probability of such atoms with respect to the minimum value of the energy required for lithium in the crystal lattice to move to the adjacent site has a normal distribution, ② In 6Li and 7Li, the standard deviation of the normal distribution is the same and the energy average the values are different. Then, in a narrow energy region near the activation energy of 6Li or 7Li transfer, it is expected that the ratio of 6Li in the energy transfer lithium decreases linearly with the increase in energy. Our experimental results seem to follow this prediction.

[1] S. Honda, K. Shin-mura and K. Sasaki, J. Ceram. Soc. Japan, 126, [5], 331-335 (2018).