bluuebunny/crossref_metadata_2025 huggingface dataset:
In-Situ Soft X-Ray Spectromicroscopy Characterization of Electrochemical Processes
Authors: Zhang Chunyang , Ingino Pablo , Obst Martin , Shahcheraghi Ladan , Yuan Hao , Eraky Haytham , Wang Jian , Higgins Drew , Hitchcock Adam P.
Published: December 2020

Soft X-ray Scanning Transmission X-ray microscopy (STXM) is a synchrotron-based technique which can provide both spectroscopic characterization (near edge X-ray absorption fine structure, NEXAFS) and chemically selective imaging with high spatial resolution (~30 nm). Recently, we have developed in situ flow electrochemical devices [1,2] which allow control of the electrochemical environment while conducting STXM measurements, thus providing a platform for in-situ studies of electrochemical oxidation and reduction processes. This presentation reports results of in situ flow electrochemical STXM studies on three different systems to demonstrate the present capabilities. First, the ability to rapidly exchange the electrolyte is demonstrated by a STXM Fe 2p and in situ electrochemical study of the ferro/ferricyanide solution redox system. Second Cu and Ag-doped Cu catalysts for CO2 electrochemical reduction (CO2R) were successfully prepared using in situ electrodeposition. Third, the electrolyte was changed from CuSO4 to NaHCO3 (as substrate for CO2R) and the cell was operated under electrochemical CO2 reduction conditions, while monitoring the changes to the Cu deposited layer at various potentials, including –0.5 V where CO2 reduction is expected [3]. The figure shows a cyclic voltammogram (CV) and color-coded Cu oxidation state maps which were derived from Cu 2p stacks measured under chronoamperometric conditions at the indicated potentials. These results demonstrate that in situ flow electrochemical STXM measurements can be performed in our device under varying electrochemical reaction conditions, enabling visualization of the morphology changes from selective energy imaging, and quantitative tracking of electrochemical transformations from spectromicroscopy. This system will be used for in situ studies of CO2 electrochemical reduction catalysis with the goal of obtaining mechanistic insights to guide the development of catalysts with improved efficiency and selectivity. In addition, the system will be used to study a variety of material science, chemistry and environmental science related questions associated with oxidation or reduction processes, such as mechanisms of extra-cellular electron transport in marine sediment microbial biofilms [4].

This research is supported by NSERC (Canada). STXM measurements were performed at the ambient STXM facility at the Canadian Light Source, which is funded by the Canadian Foundation for Innovation.

[1] V. Prabu et al., Rev. Sci. Inst. 89 (2018) 063702.

[2] P. Ingino, et al., in preparation

[3] L. Wang, D.C. Higgins, et al., Proc. Nat. Acad. Sci. (2020) 01821683. DOI: 10.1073/pnas.1821683117

[4] M. Obst, et al., Microsc. Microanal. 24 (S-2) (2018) 502-504.

Figure 1
In-Situ Electrochemical Mapping of Lithium-Sulfur Battery Interfaces Using AFM-SECM
Authors: Mahankali Kiran , Thangavel Naresh kumar , Arava Leela Mohana Reddy
Published: December 2020

Although lithium-sulfur (Li-S) batteries hold significant promise as the next-generation technology to replace lithium-ion batteries, their development is still hampered by several challenges such as rapid capacity fade, short cycle life, and poor coulombic efficiency(1, 2). To address these issues, extensive research efforts were devoted to finding better electrode and electrolyte materials. However, only a limited emphasis was given towards understanding the true nature of lithium polysulfides (LiPS) interactions at the electrode/electrolyte interface mainly due to the nonexistence of a comprehensive tool to grasp the working mechanism in real-time. While much of the in-situ studies envisage the nature of LiPS reactivity along with their chemical identity in different electrolytes(3-6), a detailed temporal and spatial mapping of LiPS interactions on the electrode surface is not explored much(7, 8).

Herein, we introduce the atomic-force-microscopy-based scanning electrochemical microscopy (AFM−SECM) technique to study the Li−S interfacial redox reactions at nanoscale spatial resolution in real-time. In situ electrochemical mapping of the discharge end products during oxidation revealed heterogeneity in the particle’s electrochemical activity and spectroscopic evidence demonstrated the presence of Li2S and Li2S2 species. During charging, Li2S2 was found to undergo facile oxidation compared to Li2S to produce intermediate LiPS. Subsequently, the unoxidized Li2S chemically/electrochemically reacts with the intermediate LiPS. At higher oxidation potentials, the as-reacted LiPS turns into insulating products, which accumulate over cycling, resulting in the reduction of active material utilization and ultimately leading to capacity fade. The interdependence of the topography and electrochemical oxidative behavior of Li2S on the carbon surface by AFM−SECM reveals the Li2S morphology−activity relationship and provides new insights into the capacity fading mechanism in Li−S batteries.

References:

(1) Xu, I. Belharouak, X. Zhang, R. Chamoun, C. Yu, Y. Ren, A. Nie, R. Shahbazian-Yassar, J. Lu and J. C. Li, ACS Appl. Mater. Interface., 6, 21938 (2014).

(2) Xu, J. Lu and K. Amine, Adv. Energy. Mater., 5 (2015).

(3) L. Wu, L. A. Huff and A. A. Gewirth, ACS Appl. Mater. Interfaces., 7, 1709 (2015).

(4) Barchasz, F. Molton, C. Duboc, J. C. Lepretre, S. Patoux and F. Alloin, Anal. Chem., 84, 3973 (2012).

(5) Zhang, Z. W. Zhang, H. J. Peng, J. Q. Huang and Q. Zhang, Small Methods, 1, 1700134 (2017).

(6) Liu, G. Zhou, A. Yang, X. Yu, F. Shi, J. Sun, J. Zhang, B. Liu, C. L. Wu and X. Tao, Proc. Nat. Acad. Sci., 116, 765 (2019).

(7) Ji and L. F. Nazar, J. Mater. Chem., 20, 9821 (2010).

(8) Manthiram, Y. Fu, S. H. Chung, C. Zu and Y. S. Su, Chem. Rev., 114, 11751 (2014).
(Invited) A Real Time Platform for Observing Surface Processes at Activated Battery Cathodes:Resolving CO2 and O2 Evolution
Authors: Mishra Abhiroop , Rodríguez-López Joaquín
Published: December 2020

Understanding the impact of surface catalysis on the interfacial evolution of battery electrodes during energy storage is key to developing reliable, efficient, and safe high-energy density technologies. The formation of interphases is essential for the operation at anodes, where the solid-electrolyte interphase (SEI) kinetically stabilizes the electrode; recently, the formation of interfacial structures at high-energy density cathodes has also garnered great interest due to the kinetic and Coulombic limitations it places on the performance of various promising materials. [1] Elucidating how electrode surface structure, composition, and potential-dependent behavior impact the degradation reactions of the electrolyte and solvent is a fundamental pursuit with significant practical implications, as it may be key to engineering safe devices and to improve the efficiency of growing and aging stable interfaces at an industrial scale. Thus, understanding how surface reactions prompt the evolution of interfaces is a pressing challenge. While X-ray and mass-spectrometric methods [2,3] have been used to characterize these chemistries, probing the surface chemistry of these electrodes with higher versatility, in situ and with high spatiotemporal and chemical resolution represents a formidable analytical challenge.

Here, we present an analytical methodology based on the use of scanning electrochemical microscopy in various modes for quantitatively detecting the formation, in real time and with high spatial resolution, of gaseous by-products such as O2 and CO2 from the catalytic decomposition of the electrolyte/solvent at battery electrodes. Using the generation/collection mode we developed an analytical platform capable of resolving these two species in order to quantify material degradation processes as a function of state of charge, and by using the feedback mode we can simultaneously monitor their impact on the interfacial kinetics of the electrode. By insightfully using ultramicroelectrode methods, and principles of CO2 electroreduction, we evaluated the nonaqueous reaction mechanisms involved in the detection to provide quantitative guidance on the relationship between the detected signal and the quantification of the processes undergoing at the battery electrode. We tested the response of our probes on a model NMC cathode, confirming O2 and CO2 evolution processes under conditions reported to exhibit bulk decomposition and surface passivation, respectively. This work creates a foundation not only for the high spatiotemporal evolution of interfacial processes at battery electrodes, but also for the understanding of CO2-related mechanisms in nonaqueous solvents.

[1] Li, W. et al. Nature Comm.
2017, 8, 14589

[2] Li, Q. et al. ACS Appl. Mater. Interfaces
2020, 12, 2, 2319–2326

[3] McCloskey, B.D. et al. J. Phys. Chem. Lett.
2012, 3, 997-1001
Bifunctional Nickel and Copper Electrocatalysts for CO2 Reduction and the Oxygen Evolution Reaction
Authors: Pan Hanqing , Barile Christopher J.
Published: December 2020

In this study, a bifunctional electrocatalyst for CO2 reduction and the O2 evolution reaction (OER) was constructed from the electrodeposition of cuprous oxide (Cu2O) and Ni on a carbon substrate. Different Ni thicknesses on Cu2O were achieved by varying the time of chronopotentiometric deposition of Ni. Electrochemical CO2 reduction was carried out at -0.89 V and -1.89 V vs. RHE, and it was found that formate and CO were the two major products. Cu2O modified with a Ni overlayer with a thickness of ~700 nm resulted in the highest formate Faradaic efficiency of 18%, and Cu2O resulted in highest CO Faradaic efficiency of 7.9%. The enhanced Faradaic efficiency for formate is attributed to the synergistic effect between Ni and Cu2O due to maximized amounts of exposed bimetallic sites that facilitate CO2 reduction. The electrocatalyst also produces ~9 times more current density than previous studies using Ni-Cu2O electrocatalysts for the OER. The ability of the Ni-Cu2O thin films to catalyze both the OER and CO2 reduction allows them to be incorporated in the first demonstration of a two-electrode CO2 conversion device with a bifunctional catalyst.
(Invited) The Role of Alkali Cation during the Electroreduction of CO2 in Aqueous Media
Authors: Co Anne C. , Zhang Fen
Published: December 2020

Using Au as a model catalyst where CO is the only product, we show that the CO oxidation peak shifts by -86 ± 2 mV/pH during CO2RR, which can be used to quantify the local pH change near the catalyst surface during electrolysis. We then applied this methodology to investigate the role of cations in affecting the local pH during CO2RR and find that during CO2RR to CO on Au in a MHCO3 buffer (where M is an alkali metal), the experimentally measured local basicity decreased in the order Li+ > Na+ > K+ > Cs+, which agreed with an earlier theoretical prediction by Singh et al.
Multi-Component Composite Oxides for Superior Oxygen Evolution Reaction Performance
Authors: Nguyen Thi-Xuyen , Ting Jyh-Ming
Published: December 2020

As a part of the effort for realize clean and renewable energy, substantial attentions are currently being paid to hydrogen generation. Of great interest is the electrocatalyst water splitting, one of the most effective ways to produce hydrogen. However, the hydrogen generation efficiency is still less than desirable due to the slow anodic oxygen evolution reaction (OER) due to primarily there are four electrons involved in the OER. Many multi-metal oxides have therefore been intensively investigated. In the paper, we report various novel oxide systems, each consisting of multiple metals for use as high performance OER electrocatalysts. The oxides were synthesized using a facile wet chemical method. The multi-metal oxides obtained include perovskite La(Mn1-xMx)O3, spinel (Fe,Co,M)3O4, and Fe5V15-xMxO39(OH)9
.9H2O, where M represents multiple metals. The material characteristics were examined using X-ray Diffractometry (XRD), scanning electron microscopy (SEM), tunneling electron microscopy (TEM), and X-ray photoelectron spectrometer (XPS). Electrochemical properties were evaluated using Multi AUTOLAB M204. Leaner sweep voltammetry (LSV) was carried out in at 5 mV/s within a potential window of 0 to 0.8 V. Stability test was carried out at 100 mV/s for 3000 CV cycles within a potential window of 0 to 0.8V. Excellent catalytic performance is demonstrated.
First-Principles Analysis of Coverage, Ensemble, and Solvation Effects on Selectivity Trends in NO Electroreduction on Pt3sn Alloys
Authors: Deshpande Siddharth , Greeley Jeffrey
Published: December 2020

Nitrogen cycle electrochemistry is an upcoming area of interest in the chemical and environmental engineering communities, with applications ranging from removal of nitrates from wastewater streams to the development of fundamental understanding of NO electrochemistry. In spite of a significant amount of fundamental research for this chemistry on single crystal surfaces, however, the mechanistic details of the reactions are not fully known.

In this work, we begin by describing a detailed analysis of the reaction mechanism of NO electroreduction on PtSn alloys. These alloys are of interest because they have been experimentally shown to be selective to products such as hydroxylamine (NH2OH) in acidic solutions, which is a more valuable product compared to NH3, the only product formed on pure platinum surfaces. In spite of this interest, however, little is known about the structural and electronic features of the PtSn that cause this selectivity change.

To elucidate these features, we make use of periodic Density Function Theory calculations combined with theoretical electrochemistry analyses. We first present our analysis for low coverages of NO present on the Pt3Sn(111) surface and derive preliminary conclusions about the reaction mechanism. Subsequently, we introduce an in-house graph theory based tool to efficiently estimate higher coverage structures of adsorbed NO on the Pt3Sn(111) surface, and we extend the kinetic analysis to the limit of higher NO coverages, resembling the state of a real catalyst under continuous reaction conditions. Further, we compare the mechanistic insights for NO electrochemical reduction on Pt-Sn alloys with that on Pt(111) and Pt(100) surfaces, to understand the role of ‘Sn’ in promoting the selectivity to NH2OH. We close by suggesting design strategies to tune the selectivity of NO electroreduction to desired products, including N2 and hydroxylamine, on other transition metals and alloys.
Off-Grid Electrocatalytic Water Treatment Combined with CO2 Conversion Driven By Photovoltaic Cells
Authors: Park Hyunwoong , Choi Wonjung
Published: December 2020

This study purposes the development of off-grid electrolysis system combined water treatment with CO2 conversion driven by sunlight. To enhance the low faradaic efficiency (FE) of (in)organic contaminant decomposition because of competition with water oxidation, reactive chlorine species (RCS), produced by chloride oxidation, is used to oxidizing agent for contaminant in aqueous solution. We conducted a research focused on arsenite (As(III)), a common and highly toxic pollutant in aqueous system, and proved that the presence of chloride in aqueous solution doubled FE of As(III) oxidation. CO2 reduction reaction (CO2RR), which is the counter reaction of improved anodic reaction, is carried out on electrodeposited Bi nanoparticle electrocatalyst, and produced formate. Formate was produced with FE of 100 % on Bi electrocatalyst when the electrolysis system was satisfied with the specific condition. The overall redox system was designed to concentrate on the simultaneous driving of these two different optimized reactions without degradation the performance compare to half-reactions. Finally, a stand-alone hybrid system operated without external power was developed through a combination of solar cells and hybrid system. In order to efficiently operate the PV-electrolysis hybrid system, the conditions of the solar cells were optimized to suit the power demands and experimental conditions of each hybrid system. As a result, the PV-electrolysis hybrid system with a solar-to system conversion efficiency more than 10% was implemented, and there were no difference in FE of the redox reaction compared to when it was operated using an external power source.
3D Capacitive Deionization Electrode Supported By Carbon Fiber/Felt Framework with Ordered Macropores for Brackish Water Desalination
Authors: Wang Yang , Lado Julio , Zhao Cong , Garcia - Quismondo Enrique , Palma Jesus , Anderson Marc A.
Published: December 2020

Capacitive Deionization (CDI) is an emerging technology for brackish water desalination. To achieve scaling electrodes with a commercial mass loading, carbon fiber/felt was employed as framework to build 3D composite electrode. The highly conductive carbon fiber/felt can serve as electron transfer channel and also provide macrostructure while activated carbon (AC) with microstructure was loaded to furnish ionic adsorption sites. The electrochemical characterization of 3D composite with carbon felt (1 cm2) showed a larger total ion storage capacity (25 F g−1, 40 mg cm−2, 0.79 F) as compared to an AC film electrode (93 F g−1, 1.5 mg cm−2, 0.11 F). It was then tested in a 10 cm2 CDI cell reaching salt adsorption capacity (SAC) values of 5.2–8.7 mg g−1 and 57–67% in charge efficiency. In addition, the 3D composite was scaled to a 300 cm2 stack demonstrating excellent performance (8.7 mg g−1SAC, 2.6gSALT m−2 h−1 and 63% charge efficiency). Similarly, the 3D composite with carbon fiber as the framework and ordered macropores by the introduction and removal of a second fiber showed lower ohmic drop and higher deionization performance than the AC film electrode and also the ones with only carbon fiber. Therefore, these 3D composite electrode supported by carbon fiber/felt framework can be a great promise for large-scale CDI practical applications.
As(III) Oxidation Mediated By Reactive Oxygen Species in-Situ-Generated from Pre-Photocharged TiO2 and WO3 Composite Catalyst Membrane Filters
Authors: Park Jiyeon , Park Hyunwoong
Published: December 2020

The photocatalytic oxidation system has been widely investigated as a pretreatment process for efficient removal of arsenic. However, its practical use for the arsenite (As(III)) oxidation is limited by several problems such as low oxidation efficiency under dark condition and difficult separation of catalysts from treated water. This study investigated light-charged TiO2 and WO3 (TW) composite-embedded inorganic membrane filter system as a practical method for preoxidative treatment of As(III) even without the addition of chemical oxidants under dark condition. And this study demonstrated that reactive oxygen species (ROSs ; O2
·- and HO2
·) in pre-photocharged TW composite catalyst membrane filter. TW membrane filters were charged under UV or simulated solar light (AM 1.5; 1 sun) irradiation and subsequently transferred to a once-through flow type system for testing As(III) oxidation in the dark condition. The As(III) oxidation efficiency increased with increasing photocharging time, weight ratio of WO3 and solution pH. These conditions enable the sufficient generation of ROSs via O2 reduction using electrons accumulated in TW during pre-photocharging for achieving the effective oxidation of As(III) in the dark condition. The oxidation capability of TW system was completely recovered after re-photocharging. TW-embedded membrane filter system can be easily reused after recharging process without the requirement of additional physical separation steps under ambient dark condition.
Disposable Stochastic Sensors Based on Nanolayer Depositon(s) of Silver, and AgC Composite on Plastic for the Assay of α-Amylase in Whole Blood and Saliva
Authors: Van Staden Raluca , Moscalu-Lungu Alexandrina , Badulescu Marius
Published: December 2020

Nanolayer deposition(s) of Ag, and AgC composite on a plastic substrate was used to design disposable stochastic sensors. The first sensor was based on an Ag nanofilm deposited on plastic; for the second sensor, an AgC composite was deposited on plastic, and for the third sensor on the plastic was deposited first a nanofilm of Ag, and on top of it a nanofilm of the AgC composite. α-Cyclodextrin was used to modify the active surface of the sensor. Wide linear concentration ranges were obtained as follows: for de assay of α-amylase in whole blood: 1.00x10-7-1.00x103 U mL-1, and for the assay of α-amylase in saliva: 1.5x10-15 - 1.5x102 U mL-1. α-Amylase was reliably determined from whole blood and saliva samples using the proposed disposable stochastic sensors.
(Keynote) Reverse Electrodialysis As a New Power Source for Sensors
Authors: Chung Taek Dong , Kwon Seung-Ryong , Baek Seol , Lee Jihye , Rho Jihun , Han Seok Hee , Yeon Song Yi
Published: December 2020

As extensive researches on renewable energy are emerging, sensory devices increasingly need appropriate power sources that supply not excessive but sufficient electricity at low cost in eco-friendly manner. Reverse electrodialysis (RED) is a promising candidate to produce electricity from the salinity difference between sea and river water. Opposite transport of ions across ion selective membrane between the aqueous solutions flowing alternatively generates electric power. Recently, research on RED has expanded not only to enhance power density but also to enable integration with other energy generation systems. The state-of-the-art of RED is compact and readily disposed. Importantly, miniaturized RED has evolved to electrodeless circuit and power patch that can be customized at will. By highlighting emerging applications of RED, this talk will focus on the introduction of recently developed miniaturized patch-type RED which can be used to power various devices. We emphasize the potential of this RED for sensors and look forward to its wide range of application scopes in the future.

Figure 1
Ni-BTC Derived Porous Ni/C/Graphene Composite for Highly Sensitive Non-enzymatic Electrochemical Glucose Detection
Authors: Li Guofu , Chen Di , Chen Yingjie , Dong Lifeng
Published: December 2020

Electrochemical detection of glucose, including enzymatic and non-enzymatic detections, has gained widespread attention due to its rapid response, unparalleled sensitivity, and common applications in both biomedical and healthcare fields. Compared with enzymatic glucose detection, non-enzymatic detection has lower cost, better stability and simpler immobilization operation. However, due to relatively inert nature of glucose and prone-to-contaminant characteristic of solid electrodes, non-enzymatic glucose detection suffers from weak sensitivity and reproducibility. To address these problems, various transition metal-based materials and graphene-based materials have been explored to improve electrochemical responses to glucose.

Herein, a highly sensitive non-enzymatic glucose detection electrocatalyst was synthesized by in-situ growing porous NiO nanoparticles derived from Ni-BTC (1,3,5-Benzenetricarboxylic acid) on graphene (NiO/G). By virtue of highly porous Ni-BTC as a precursor, the composite exhibited homogeneous metal distribution, massive exposure of active sites, and spatially ordered structure. The NiO/G demonstrated superior steadiness, electron transfer rate, excellent electrocatalytic activity towards glucose oxidation, and high sensitivity (1030 μA mM−1 cm−2) in alkaline media. Thus, the NiO/G can be utilized as electrocatalysts for applications in non-enzymatic glucose detection, and the preparation strategy can be used to synthesize other nano-composites with low cost, such as CuO/G and Co/G, for non-enzyme glucose sensors.
(Sensor Division Outstanding Achievement Award Address) Paper-Based Lateral Flow Strips As Point-of-Care Testing Tools for Detection of Biomarkers and Viruses
Authors: Wu Nianqiang Nick
Published: December 2020

Biomarkers indicate human health conditions and diseases. For example, viral RNA and antigens are used for COVID-19 screening. Currently enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) are the gold standard methods for measuring protein and nucleic acid biomarkers, respectively. Both PCR and ELISA require professionals to operate in a centralized laboratory for several hours. Therefore, this presentation shows our effort to develop paper-based lateral flow strips as point-of-care testing (POCT) devices for rapid and in-field detection of proteins and nucleic acids by laypersons at clinics, home, and remote areas. Plasmonic nanostructures have been developed to enhance fluorescence or surface-enhanced Raman scattering (SERS) to improve sensitivity. Such optical sensors have been integrated with paper-based microfluidic strips to achieve automation and miniaturization. The integrated paper-based lateral flow strips have been used for detection of viruses and biomarkers of several human diseases such as traumatic brain injury and cancers.
An Enzymatic Electrochemical Biosensor for Real-Time Detection of Physiologically Relevant Nicotine Concentrations
Authors: Kuzmanovic Uros , Chen Mingfu , Tararina Margarita , Shu Nicolas , Sensharma Prerana , Gupta Anant , Fan Andy , Klapperich Catherine M. , Allen Karen , Grinstaff Mark W , Galagan James
Published: December 2020

The glucose biosensor, built upon the redox enzyme glucose oxidase, is the most commercially successful and studied enzymatic biosensor. However, the lack of available and functionally validated enzymes is prohibiting the development of redox-based sensors for other important analytes. Herein, we present the development and assessment of an electrochemical nicotine biosensor, using genomic screening to identify the gene for a known nicotine catabolizing redox enzyme. The resulting nicotine biosensor demonstrated a specific, sensitive, and stable operational profile with a limit of detection of 27 μM over the range of 0-200 μM. This range is well within the physiological concentrations of nicotine present in smoker urine. Specificity and cross-reactivity were measured against structurally similar compounds to nicotine as well as to known physiological by-products. Our results highlight that this novel enzymatic electrochemical nicotine biosensor possesses operational capabilities for monitoring of nicotine in physiologically relevant conditions. The screening methodology can be generalized for the discovery of enzymes for novel sensor development.
Electrochemical Detection Method Using Serotonin Oxidation inside a Single Human Platelet
Authors: Lee Jungeun , Kim Byung-Kwon
Published: December 2020

An early diagnosis of platelet-related diseases is important for maintaining a healthy human life for blood clotting disorders caused by internal and/or external stimuli. Various technologies based on physics and chemistry have been developed for the detection of platelets. These methods are mainly set up in clinical laboratory and hospitals, cannot be portable, and require both complex pretreatment procedure and expensive detectors for platelet detection. Platelets are one of the human blood compositions and an important role in blood coagulation. Therefore, it is necessary to develop a method that can be adopted as a medical device capable of diagnosis in everyday life. We proposed an electrochemical collision method for direct detection of serotonin in a single platelet from human blood. This method is based on collisions of platelets with an ultramicroelectrode (UME) and observed the oxidation signal of serotonin without any modification of electrode through single-entity electrochemistry (SEE). When a platelet collides with the UME, secreted serotonin from the platelet gets oxidized at the electrode surface generating anodic currents. In our methods, the current for effective detection of platelets is very sensitive because there is no redox species. Studies on biomolecule detection through SEE can be useful for measuring the number of blood cells in our blood. Observing changes in the current that occur when platelets selectively collide with the UME, is medically useful information obtained cheaply and easily. The SEE method applied to blood analysis will be a new way to overcome the limitations of the existing sampling process, analysis time and environment. It is also expected to contribute to the development of high-performance sensors based on point-of-care-testing (POCT) devices capable of on-site and real-time diagnosis.
(Invited) Assembly of Multifunctional Nanoelectronic Sensors via Tissue Development
Authors: Liu Jia
Published: December 2020

Tissue-wide electrophysiology with single-cell and single-spike spatiotemporal resolution is critical for biological studies and biomedical applications. In this talk, I will discuss the creation of cyborg organisms: the three-dimensional (3D) assembly of soft, stretchable mesh nanoelectronics across the entire living organism by the cell-cell attraction forces from 2D-to-3D tissue reconfiguration during organogenesis. We demonstrate that stretchable mesh nanoelectronics can migrate with and grow into the initial 2D cell layers to form the 3D organ with minimal impact on tissue growth and differentiation. The intimate contact between the dispersed nanoelectronics and cells enables us to chronically and systematically observe the evolution, propagation and synchronization of the bursting dynamics and biomechanical signals in different organisms through their entire organogenesis and maturation. I will also discuss the potential applications of these cyborg organisms in biology and biomedicine.
Real-Time, In Vivo Monitoring of Pharmacodynamics in Solid Tumors Using Organic Color Centers
Authors: Kim Mijin , Chen Chen , Langenbacher Rachel E , Frederiksen Rune , Wu Xiaojian , Yaari Zvi A , Shah Janki , Wang YuHuang , Heller Daniel A.
Published: December 2020

Covalent bonding of organic functional groups to the sp2 carbon lattice can produce tunable sp3 quantum defects that fluoresce brightly in the second near-infrared (NIR-II, 1000-1700 nm). Such synthetic defects, or ‘organic color centers’ (OCCs), provide a molecular focal point that sensitively and selectively responds to the local dielectric environments. To benefit from the unique electronic and optical properties of OCCs in biomedical applications, we present a new method that controls the biological interactions/biocompatibility of OCC-based nanosensors via their supramolecular interactions with polymers and other excipients. The resultig OCC-based nanosensor measures endolysosomal pH in live cells and in vivo. We discuss the utility of the nanosensor to real-time monitor the pharmacodynamics of anticancer drugs in solid tumors.
Welcome Remarks - M03: In Vivo Nano Biosensors
Authors: Heller Daniel A. , Corrie Simon
Published: December 2020

Welcome to M03: In Vivo Nano Biosensors! Take a moment to listen to welcome remarks from the lead organizer, Daniel Heller and co-organizer, Simon Corrie.
Insight into Lithium Ion Transport Properties of Artificial Solid Electrolyte Interfaces By Molecular Dynamics Simulations
Authors: Verweyen Elisabeth , Bedrov Dmitry , Winter Martin , Brunklaus Gunther
Published: December 2020

Among the most promising technologies for the next generation of electrochemical energy storage devices are lithium metal anode based batteries. In practical application, however, issues such as parasitic reactions of lithium metal with liquid electrolytes or the transient inhomogeneous lithium deposition on the metal anode occur for these storage systems.

To enable the use of lithium metal electrodes with liquid electrolytes, an artificial solid electrolyte interface (SEI) can be introduced, which should be affordable but also enhancing the electrochemical performance as well as calendar and cycle life of the cells. The ongoing search for feasible materials suggested the copolymer poly(3,4-ethylenedioxythiophene)-co-polyethylene glycol (PEDOT-co-PEG) as a promising candidate. The PEG homopolymer is ion-conductive whereas PEDOT is electron-conductive and offers good electrochemical stability [1]. The copolymer PEDOT-co-PEG exhibits sufficiently high ionic conductivity and may stabilize lithium electrode interfaces, thereby reducing lithium dendrite growth [1].

This work includes an analysis of the lithium ion transport properties of PEDOT-co-PEG by extensive molecular dynamics (MD) simulations, exploiting the Atomistic Polarizable Potential for Liquids, Electrolytes and Polymer (APPLE&P) method. Multiple constitutions of the copolymer as well as blend polymers of both PEDOT and PEG were studied in the presence of lithium bis(trifluoromethane)sulfonamide (LiTFSI) in different concentrations, at simulated temperatures between 300 and 500 K. Notably, the impact of selected parameters not only on the resulting polymer morphology, but also on the dissociation of the lithium salt, the mean square displacement of lithium ions, the corresponding lithium coordination, as well as the lithium transport mechanism is detailed. This work affords deeper insight and comprehensive understanding of molecular processes that govern the lithium conduction, thereby paving ways for tailored design of future materials, including the development of electrode coatings and electrolyte formulations, based on which superior electrochemical performance and lifetime for lithium metal based batteries could be achieved.

References:

[1] I.S. Kang, Y.-S. Lee, D.-W. Kim, J. Electrochem. Soc. 161 (2014) 53-57.
High Dielectric, Robust Organic-Inorganic Composite Protective Layer for Lithium Metal Anode
Authors: Jang Eun Kwang , Im Jinsol , Cho Kuk Young
Published: December 2020

The development of lithium metal anodes for next-generation batteries is still a challenge. Li dendrite growth, one of the challenges, not only induces severe safety issues but also leads to capacity fading by continuously consuming the electrolyte. In this study, we demonstrate the design and fabrication of a composite protective layer to overcome these challenges. Composite protective layers exhibit high ionic conductivity and mechanical strength. This layer not only suppresses dendrite growth but also prevents salt degradation.

The composite protective layer, which exhibits synergistic soft-rigid characteristics, is placed on the Li metal anode and facilitates superior interfacial stability during long-term cycles. LiMn2O4/ coated lithium full cells using the composite protective layer enhanced capacity retention compared to the cells using bare lithium anode. The proposed strategy opens new avenues to fabricate a sustainable composite protective layer that affords superior performance in lithium metal batteries.
Study of α-MnO2 By Electrochemical Analysis in Rechargeable Aqueous Zinc-Ion Battery
Authors: Putro Dimas Yunianto , Islam Saiful , Lee Seulgi , Kim Seokhun , Park Sohyun , Kim Jaekook
Published: December 2020

Zinc-ion batteries (ZIBs) are very promising energy storage devices owing to their safety, environmental friendliness, and low-costs. Nevertheless, their development has been mostly focused on aqueous-based systems. We fabricated a quasi-solid-state ZIB based on a-MnO2 nanohusk morphology synthesized using a one-step hydrothermal method and gel electrolyte. The fabricated quasi-solid-state ZIB exhibited a high initial discharge capacity of 321 mAh/g at a current density of 33 mA/g and considerable cyclability. We systematically investigated its electrochemical properties utilizing various characterization methods such as cyclic voltammetry and galvanostatic intermittent titration technique. In addition,in-situ synchrotron X-ray diffraction and X-ray absorption spectroscopy were used to elucidate the phase transformation of the cathode in the quasi-solid-state ZIB upon electrochemical cycling. This study may provide further insight into electrochemical behaviour of the quasi-solid-state ZIB based on the a-MnO2 nanohusk morphology and gel electrolyte as a promising energy storage device.
Preperation of Br-Doped Li4Ti5O12 Anode and Its Electrochemical Performance in Li-Ion Battery
Authors: Piao JunJi , Kim Seokhun , Lee Seulgi , Islam Saiful , Kim Jaekook
Published: December 2020

In this work, we studied about Br-doped Li4Ti5O12-xBrx (“x”= 0, 0.1, 0.3, 0.5 and 0.7) anode materials, which were synthesized by a conventional solid-state reaction using precursors of Li2CO3, TiO2 and LiBr, and we found that their electrochemical properties were related to the doping behavior

Most of the Br ions are situated on the surfaces/interfaces of agglomerated particles rather than in the bulk lattice after quantitative instrumental analysis.

This lead to the formation of Narrow conduction paths of electron and Li-ion on their surfaces/interfaces.

The presence of these narrow surface electrical conduits increased the rate-capability of the LTOBr samples during charging/discharging process.

Highly Br-doped sample (LTOBr0.7) showed a slight reduction in capacity. The LTOBr0.5 sample, by the mean time, showed the highest capacity of 125 mAh/g at 1C compared to 115 mAh/g for pure LTO.

This was explained with the formation of fine precipitations (Br-containing second phase) on the surfaces of the LTO particles due to high Br addition.

The formation of fine precipitations (Br-containing second phase) on the surfaces of the LTO particles due to high Br addition could be the explanation of this.
Potassium Inserted V2O5.xH2o Nanorods As a High-Performance Cathode Materials for Cost Effective Aqueous Rechargeable Zinc-Ion Batteries
Authors: Islam Saiful , Alfaruqi Muhammad Hilmy , Piao JunJi , Kim Seokhun , Lee Seulgi , PARK Sunhyeon , Park Sohyun , Kim Jaekook
Published: December 2020

Research attention in aqueous rechargeable zinc-ion batteries (ARZIBs) is growing immensely because of their low-cost and eco-friendly cell components. However, its challenging to find new cathode materials towards practical application of ARZIBs. In this contribution, ground-breaking work on the potassium-pillared V2O5.nH2O (K0.5V2O5.nH2O) nanorod with exposed layer structure as high-performance cathode for ARZIB is presented. The storage mechanism of the K0.5V2O5.nH2O cathode in ARZIB is systematically elucidated using a combined of in situ synchrotron X-ray diffraction, ex situ synchrotron X-ray absorption spectroscopy, ex situ TEM analyses, and first-principle calculations. The K0.5V2O5. nH2O cathode displays a notable discharge capacity of 439 mAh g−1 at a current density of 50 mA g−1. Furthermore, it recovers 96% of the capacity after 1500 cycles at 8000 mA g−1. Impressively, the Zn/K0.5V2O5.nH2O battery offers a specific energy of 121 Wh kg−1 at a high specific power of 6480 W kg−1. The superior performance of the cathode is attributed to its unique exposed layer structure with high surface energy, high conductivity, and low migration barrier. The zinc (Zn) insertion pathway into K0.5V2O5.nH2O was studied using density function theory (DFT). This study provides an insight for designing high-performance cathode materials for ARZIBs and other electrochemical systems.
A Promising Positive Electrode Material for Na+/Li+ Hybrid-Ionbatteries: Monoclinic-Orthorhombic Na1.1Li2.0V2(PO4)3/C Composite
Authors: Lee Suyeong , Soundharrajan Vaiyapuri , Park Jimin , Song Moonsoo , Kim Jaekook , Hwang Jang-Yeon
Published: December 2020

In this paper, we report a new single death-to-fire Na1.1Li2.0V2 (PO4) 3 / C (NLVP / C) compound cathode synthesized from a mono-clinical LVP through a soft ion exchange reaction for use in Na+/Li+ hybrid ion batteries. Thermal studies, High Resolution Synchrotron X-ray diffraction (XRD), and electrochemical data check the room temperature stabilization of the monoclinic-orthorhombic NLVP / C composite phase. In particular, we report application of monoclinic orthorhombic NLVP / C composite as positive materials in Na half-cell. This monoclinic-orthorhombic NLVP/C composite cathode delivered a discharge capacity of 115 mAh g−1 with an average discharge potential of 3.47 V. Corresponding in situ synchrotron XRD patterns recorded during initial electrochemical cycling clearly indicate a series of two-phase transitions and confirm the structural stability of the NLVP/C composite cathode during insertion and extraction of the hybrid ions. In addition, the estimated average working potential and energy density at the initial cycle for the monoclinic orthorhombic NLVP/C composite cathode (3.47 V vs Na/Na+ and 102.5 Wh kg−1, respectively) are higher compared with those of the pyro-synthesized rhombohedral Na3V2(PO4)3 (3.36 V vs Na/Na+ and 88.5 Wh kg−1) cathode. Thus, this study shows the feasibility of using a soft ion-exchange reaction at 150 °C to facilitate the formation of composite phases suitable for rechargeable hybrid-ion battery applications.
A Self-Ion Exchange of Na0.53 MnO2+
Cathode for Li+/Na+ Hybrid Ion Battery
Authors: Oh Gwangeon , Zulkifli Z. , Park Sohyun , Song Moonsoo , Kim Jaekook , Hwang Jang-Yeon
Published: December 2020

P2-structure sodium manganese oxide is synthesized by a simple reduction reaction. The low-cost electrodes of lithium / sodium hybrid ion batteries after the ion exchange process provide new data on the direct use of sodium manganese oxide instead of lithium analogue. As observed by X-ray diffraction analysis, ion exchange occurs in sodium manganese oxide through electrolytes during cell stabilization. Its own ion exchange material has a high discharge capacity of 195 mA h g-1and a stable plateau at 3.0 V for 50 cycles. In-situ X-ray diffraction and ex-situ X-ray absorption close to edge structure studies confirm reversible oxidation reduction reactions and stable structural changes. ex-situ induced coupled plasma atomic emission spectroscopy confirms that residual sodium ions act as pillars during cycling in the structure.
Analysis of Irreversible Charge-Discharge Reaction in LiFePO4/Li4Ti5O12 Full-Cell Using Two-Phase Reaction Active Material
Authors: Omote Yuki , Katayama Misaki , Orikasa Yuki
Published: December 2020

In laboratory charge-discharge tests of lithium-ion battery electrodes is often used half-cell with a lithium metal anode, which can supply enough lithium ions. On the other hand, practical lithium-ion batteries do not contain lithium metal and use full-cell configuration with almost similar capacities between cathode and anode. Limited number of lithium ions supplied by the cathode contributes as carrier ions, which determines the actual charge-discharge capacity. Since the degradation behavior observed in full-cell is different from in half-cell [1, 2], it is important to understand the problems that occur during charge-discharge in full-cell to maximize battery performance. In this study, we investigated the irreversibility in full-cell with lithium iron phosphate (LiFePO4) cathode and lithium titanate (Li4Ti5O12) anode as an unnatural case, where both active materials show two-phase reaction in almost all composition. The potential changes of cathode and anode were tracked using the three-electrode full-cell with a lithium metal reference electrode. In addition to the electrochemical measurements, the charge-discharge state was analyzed from the X-ray absorption spectroscopy (XAS), which provides the valence change information.

Half-cell charge-discharge tests of LiFePO4 and Li4Ti5O12 at 0.1C result in reversible charge-discharge profile. However, the distinct irreversible capacity is observed in the LiFePO4 / Li4Ti5O12 full-cell configuration. The initial charge and discharge capacity are 162 nd 126 mAh g-1, respectively and this irreversibility is continuously observed in the subsequent cycle. The three-electrode test indicates that the potential of Li4Ti5O12 anode sharply increases despite in the middle of the discharge. Fe K-edge XAS shows similar edge energy for the half-charged and half-discharged LiFePO4 cathode. However, Ti K-edge XAS of half-charged Li4Ti5O12 anode shows the different edge energy from that of the half-discharged. The full-discharged LiFePO4 cathode does not reach the lithiated state even after discharging, which agrees with the results from the three-electrode test. At the end of the charge, little edge-energy shift in the Li4Ti5O12 anode is observed, indicating that the insertion reaction of lithium ions does not progress. Therefore, the irreversible capacity is caused by a side reaction at the Li4Ti5O12 anode in end of the charge.

[1] Bjorklund, D. Brandell, M. Hahlin, K. Edstrom, R. Younesi, J. Electrochem. Soc
., 164 (2017) A3054-A3059.

[2] H. Kim, N.P.W. Pieczonka, Z.C. Li, Y. Wu, S. Harris, B.R. Powell, Electrochim. Acta. , 90 (2013) 556-562.
One-Pot Pyro-Synthesis of a High Energy Density LiFePO4-Li3V2(PO4)3 Nanocomposite Cathode
Authors: Park Jimin , Chatterjee Shubham , Park Sohyun , Kim Jaekook , Hwang Jang-Yeon
Published: December 2020

Highly crystalline carbon-coated 0.66LiFePO4•0.33Li3V2(PO4)3(LFP-LVP) nanocomposite was synthesized by a one-pot pyro-synthetic strategy by a polyol medium at low temperature. In this article, electron microscopy delivered the as-synthesized composite consisting of spherical particles with average diameters in the range of 30–60 nm. Following heat treatment, a crystal growth phenomenon and particle aggregation was observed at 800 °C, thus resulting in an increase in the average particle size to 200– 300 nm. Testing for a lithium-ion cell, the nanocomposite electrode provided good electrochemical properties with higher operating potentials hence enhanced energy densities and excellent rate capacity. Corresponding to an energy density of 46.88 Wh Kg−1 at 6.4 C, the composite cathode showed a high reversible capacity of 156 mAh g−1 at 0.1 C and exhibited a remarkable reversible capacity of 119 mAh g−1. Moreover, when cycling was performed at 6.4 C, the electrode can recover up to 85% of the capacity at low current density of 0.1 C. As a result, the enhanced performance was attributed to the inclusion of the high potential LVP phase constituent in the present cathode using a simple one-pot polyol-assisted pyro strategy.
Coordination Complex Templated Battery Materials
Authors: Shuaib Umaira , Powell Annie K.
Published: December 2020

Transition-metal oxides (TMOs) have plenty of applications across many different fields of science; solar cells, gas sensors and the electronics industry are some of the areas where the progression from research to application has been extremely rapid. Manganese oxides (MnOs) are a common and commercially available active material used in the electrodes of energy storage devices such as batteries, because they have a higher theoretical capacity (c.a. 756 mAh g-1) compared to the conventional anode material graphite (372 mAh g-1). As shown in the ‘cycling stability’ graph, nearly 600 mAh g-1 of discharge capacity can be obtained during the first 40 cycles, followed by a gradual drop in capacity to 420 mAh g-1 before increasing again after the 82nd cycle and surpassing the initial 600 mAh g-1 after the 135th cycle.

While suggesting a reaction has taken place during long-term cycling (e.g. phase conversion), the isosbestic points in the insitu XAS studies aren’t necessarily correlated to CTAM behaviour. Alternate reactions in the electrode causing changes in the mechanism during the discharge profile are present. The radial distance between 1 and 2 Å is much lower than expected for the Mn-O bond. In the graph portraying the potential against time, we can see at 0.4 V the capacity is held at a stable potential between 10 h to 28 h.

Here we explored the unique electrochemical behaviour of these simple and sustainable oxides templated from metal-organic frameworks (MOFs) as a competitor for graphite and current oxide-anodes.

Figure 1