bluuebunny/crossref_metadata_2025 huggingface dataset:
Glucose Detection Using Molecularly Imprinted Mesoporous Organosilica
Authors: Jimenez-Monroy Kathia , Caldara Manlio , Eersels Kasper , Diliën Hanne , van Grinsven Bart , Cleij Thomas J.
Published: July 2021

Since the first developments in Molecular Imprints, the general approach is to crosslink a polymeric network around a target molecule, which serves as a template. After removing the target imprint, the remaining polymer keeps the shape and functional groups for rebinding with the target molecule. Therefore, Molecularly Imprinted Polymers (MIPs) are also known as artificial antibodies.

In the context of sensing applications, the advantages of using MIPs over natural antibodies range from higher stability at different measuring conditions (eg. solvents, pH, etc.) to longer shelf-life. However, the hydrophobic nature of polymers might play a role in the sensitivity of measurements performed in aqueous solvents, for example to detect contaminants in food samples.

To tackle this problem, we use hydrophilic mesoporous organosilica polymers to detect glucose in real time. Sensitivity and selectivity tests were performed using the developed organosilica MIP and the corresponding Non-Imprinted Polymer (NIP). Rebinding isotherms were calculated using uv-vis spectroscopy, Impedance and Heat-transfer method (HTM).
Multiplexed Bioanalysis Based on Light-Sensitive Electrodes
Authors: Zhao Shuang , Riedel Marc , Yue Zhao , Parak Wolfgang , Lisdat Fred
Published: July 2021

Introduction

Quantum dots (QDs) have become attractive tools in bioanalysis because of their advantageous optical and electrochemical properties. This relates to applications exploiting fluorescence, electrochemiluminescence or photocurrent generation [1]. For the latter case QDs are immobilized on conductive electrodes. By light excitation charge carriers are formed inside the nanoparticles which can be used for photocurrent generation. Signal chains can be constructed when appropriate donor or acceptor components are present in solution. The special feature of such electrodes is that the response is triggered by illumination of the sensing electrode [1]. In this study, a light-addressable photoelectrochemical sensor was built by coupling QDs with oxidases to detect different enzyme substrates.

Results and Conclusions

First CdSe/ZnS QDs have been immobilised via a dithiol compound on gold electrodes. Two different enzymes, glucose oxidase (GOD) and sarcosine oxidase (SOD) have been deposited on this QDs-electrode at spatially well resolved places. Here small spots have been achieved by a dropping method. A laser beam is moved over the spots to detect photocurrents. Since oxygen can act as electron acceptor at the illuminated QDs the photocurrent is correlated to the oxygen concentration in solution. By action of the enzymes in the presence of the corresponding substrate a competitive situation for oxygen is created in front of the QD layer and thus, the photocurrent decreases [2, 3]. Since this happens in a concentration dependent way, analysis of the enzyme substrate is feasible.

Furthermore, due to the spatially separated immobilisation of the two enzymes, an independent read-out of the two enzyme reactions is possible. The results indicate good lateral resolution and selectivity of the multi-detection system without any crosstalk between the two sensing regions and also without any response at regions, which have not been modified with an enzyme [4].

After that, the possibility of an imaging of the enzyme spot by photocurrent measurement has been studied. When the laser is moved over the spot of GOD with a constant speed, the size of the spot can be determined from the photocurrent - time curve (with a defined moving speed). The photocurrent correlates to different local enzyme activities. Consequently, an imaging of the enzyme activity distribution on the surface has also been achieved by this method.

References

[1] F. Lisdat, D. Schäfer, A. Kapp, Analytical and Bioanalytical Chemistry 405 (2013) 3739-3752

[2] M. Riedel, et al., Chem. Phys. Chem. 2013, 14, 2338-2342.

[3] J. Tanne et al., Anal. Chem. 2011, 83, 7778-7785.

[4] S. Zhao et al., ACS Applied Materials & Interfaces, 2019, Vol. 11 (24), p. 21830-21839
Aggregation Effect in Polymer Graphene Composites for Optical Sensing Applications
Authors: Barkley Jennifer , Reyes-Rosa Lianis , Han Shubo , Siamaki Ali , Gautam Bhoj
Published: July 2021

We measured the aggregation behavior of polyfluorine (PFO) films blended with graphene oxide (GO) and reduced graphene oxide (RGO) using optical spectroscopy spectroscopy. We observed the changes relative intensity of 0-0 to 0-1 in the emission spectra in polymer graphene composite films. The composite films have more H like aggregation compared to pristine film. In addition, strong photoluminescence quenching observed in PFO-RGO compared to PFO-GO. Our study shows that polymer graphene composites can be used as optical sensing materials.
Soft Electrochemical/Electronic Devices and Their Applications in Point-of-Care Testing
Authors: Li Fei
Published: July 2021

Using soft materials (e.g., paper, hydrogel) to replace the traditional hard materials (e.g., glass, silicon) as substrates have become a recent trend in developing point-of-care testing (POCT) platforms. And through integration of the soft materials with electrochemical or electric devices can further extend the applications of POCT. In our recent work, we used four kinds of soft materials, including paper, PDMS, hydrogel and liquid marble, as the new soft substrates of POCT platforms and realized their new applications in POCT. For example, by integration of the electrodes and hydrophobic channels on paper through simply writing method using home-made pens, the fabricated paper-based electrochemical devices have been successfully applied to detect glucose in artificial urine and melamine in sample solutions. By fabrication of MWNTs/PDMS fibers as multifunctional sensors and integration them on a glove, the measurement of gesture recognition and temperature have been realized by the “smart” glove. Through injection of liquid metal into the 3D helical structure of hydrogel and combination the hydrogel with electronic sensing device, the temperature, UV sensing and EMG signal detections have been performed by the wearable, multifunctional hydrogel device. By using liquid marble as a separator and small device for isoelectric focusing, the POCT separation and analysis of proteins have been realized. The proposed new soft platforms show wide application potential in POCT.

References

[1] J. C. Niu, H. X. Shi, H. G. Wei, B. Gao, J. Li, F. Xu, X. G. Li, F. Li, Liquid Plasticine Integrated with Isoelectric Focusing for Miniaturized Protein Analysis, Analytical Chemistry. 2020, 92, 9048

[2] H. Liu, M. X. Li, S. B. Liu, P. P. Jia, X. J. Guo, S. S. Feng, T. J. Lu, H. Y. Yang, F. Li, F. Xu, Spatially Modulated Stiffness on Hydrogel for Soft and Stretchable Integrated Electronics, Material Horizons. 2020, 7, 203

[3] Z. D. Li, H. Liu, X. C. He, F. Xu, F. Li, Pen-on-Paper Strategies for Point-of-Care Testing of Human Health, Trac-Trends Anal. Chem. 2018, 108, 50.
Neuropeptide Y Detection Using Aptamer-Modified Electrodes By Electrochemical Impedance Spectroscopy
Authors: Lopez Luis F. , Martinez Lyza , Lozano Kelly , Cunci Lisandro
Published: July 2021

The advantages of using carbon fiber, gold or platinum as electrodes are because they are promising materials with high electrical conductivity, chemical stability, and high surface area that can be easily modified on their surface. The immobilization and biofouling of the surface of the electrodes were studied and compared using Electrochemical Impedance Spectroscopy (EIS). Adsorption of NPY to the aptamer-modified microelectrodes was also demonstrated by EIS with the specificity provided by aptamer functionalization of the electrode surface. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Atomic Force Microscopy (AFM) was used to characterize the morphology, the elemental composition, and the topography of the electrodes before and after the aptamer modification, respectively. NPY concentrations from the range of pg/mL to ng/mL were detected to the see the interaction between the modified electrodes and our target. These results give us a great approach of measure NPY using EIS.
(IMCS First Place Best Paper Award) Local Hypoxia System as a Sensing Interface of Cellular Responses
Authors: Wong Joseph Jo Yin , Varga Balazs , Karadottir Ragnhildur Thora , Hall Elizabeth A.H.
Published: July 2021

Oxygen concentration is one of the critical factors tightly controlled in each part of an organism to regulate the cells’ role and function. Yet, changes in tissue oxygenation often occur in small focal areas with aging or as a result of an injury. Despite the serious health implications of focal hypoxia, no methodologies exist that can model oxygen supply system accordingly in animal models or in vitro models. Therefore, we designed a novel local hypoxia system as a sensing interface for in vitro cell culture. The oxygen removal efficiencies measured by Clark electrodes showed that O2 concentration can be reduced from 20.9% / 140mmHg or 5% / 35mmHg and maintained at hypoxia (< 1.5% / 10mmHg) in 15 or 8 minutes respectively, compared with 3 hours needed by conventional incubator and hypoxic chambers. The induced hypoxia stimulated localized time-dependent HIF-1α transcription factor nuclear accumulation at the region of interest on human neural progenitor cells. This new culture system can robustly generate a hypoxia gradient in the same culture dish for the first time and provides the opportunity to decipher the impact of focal hypoxia, the function of localised oxygen homeostasis and the pathophysiology of multiple diseases.
Layer by Layer Assembly of Graphene Oxide and Reduced Graphene Oxide for Electrochemical Oxidation of Bisphenol
Authors: Ahammad A. J. Saleh , Hasan Md. Mahedi , Islam Tamanna , Sarker Subrata
Published: July 2021

Here, we report fabricating graphene oxide (GO)_GO, GO_reduced graphene oxide (rGO), rGO_rGO, and rGO_GO electrodes through screen printing and study their electronic structure and properties for electrochemical oxidation of bisphenol A (BPA). The electroanalytical techniques used were cyclic voltammetry, Tafel analysis, electrochemical impedance spectroscopy (EIS), and chronoamperometry. The electron transfer mechanism for all the systems were investigated for BPA analyte. Though the research is just in its infancy, analysis of the data obtained so far showed that BPA interacted differently with each of the systems. The BPA oxidation peak current (Ipa) and peak potentials (Epa) for GO_GO, GO_rGO, rGO_rGO, and rGO_GO were determined to be: 1.93 µA @ 0.51 V; 1.47 µA @ 0.5 V; 0.8 µA @ 0.53 V; and 3.6 µA @ 0.5 V; respectively. Tafel slope analysis yielded values of 32.45 mV/dec for GO_GO, 55.4 mV/dec for GO_rGO, 70 mV/dec for rGO_rGO, 90.1 mV/dec for rGO_GO. These different values of Tafel slope indicates that the electron transfer kinetics is different for each of the systems. We intend to thoroughly investigate the interlayer interaction (ILI) process for these four different setups and how they contribute to the electrode/electrolyte interfacial charge transfer process.
(Invited) Chemical Sensing Based on Metal-Carbon Nanocomposites
Authors: Chen Shaowei
Published: July 2021

Detection of hydrogen peroxide is of great significance for clinical diagnosis and biomedical research. Ratiometric detection represents an effective method that is generally based on horseradish peroxidase. In this presentation, we will show that ruthenium ion-complexed carbon nitride (Ru−C3N4) nanosheets can be used as a peroxidase mimic and catalyze the conversion of o-phenylenediamine to fluorescent 2,3-diaminophenazine in the presence of H2O2. The produced 2,3- diaminophenazine also results in the apparent quenching of the Ru−C3N4 photoluminescence due to the inner filter effect. These unique characteristics can be exploited for the construction of an effective, peroxidase-free ratiometric fluorescence framework for the detection of H2O2 and glucose, which has also been used in the successful detection of glucose in human serum. Results from this study not only demonstrate a new peroxidase mimic but also provide a novel ratiometric fluorescence platform for the detection of H2O2 and metabolites involving reactions of H2O2 generation in the absence of horseradish peroxidase.
(Invited) Surface Acoustic Wave Sensors for Refrigerant Leak Detection
Authors: Thallapally Praveen K
Published: July 2021

Advanced sensors for detection of gases and vapors are required for energy and environmental monitoring. For example, detection of refrigerant leaks from HVAC equipment specifically difluoromethane at low concentrations in air is required. When a refrigerant leak occurs from a HVAC system, there are several consequences, i) reduction in cooling efficiency and ii) higher greenhouse gas emissions to the atmosphere. Sensing refrigerant leaks requires sorbents with high affinity at low partial pressures. Having a highly effective sorbent sensitive to fluorocarbon refrigerant vapors provides a means to develop a sensing device for leak detection. In this regard, Pacific Northwest National Laboratory is exploring novel classes of materials including metal organic frameworks (MOFs), covalent organic frameworks and porous organic cages as a thin film on surface acoustic wave sensor for detection of refrigerant leaks. The structure and selectivity of these materials can be tailored by the selection of various organic bridging ligands used in the synthesis. Further these materials shown to have high surface area and shown to have high gas mobility higher than many other sorbent materials. These characteristics are highly favorable for development sorptive materials for sensing refrigerant molecules from air. Our work in this area suggest these materials reflect a range of sorbent properties from high uptake capacity (over 170 wt%) at high vapor pressures to very high sorption affinities at very low vapor pressures. I will discuss methods to use these materials as a thin film on surface acoustic wave sensor for detection of refrigerant molecules
Nanostructured Molecular Imprinted Polymers for Chemosensing of Hormone Proteins
Authors: Kalecki Jakub , Cieplak Maciej , Dąbrowski Marcin , Lisowski Wojciech , Kuhn Alexander , D'Souza Francis , Sharma Piyush Sindhu
Published: July 2021

Immunoassays and high-performance liquid chromatography combined with mass spectrometry are common methods to selectively determine protein biomarkers in biological samples. The excellent accuracy of these determinations is at the expense of a high cost, including the cost of specific antibodies supply or instrumentation and experienced operation. Several biosensors were devised and fabricated for fast and selective quantification of the protein biomarkers. The most interesting protein biomarkers belong to the glycoprotein family. Unfortunately, it seems challenging to generate antibodies for this family because of low immunogenicity. Thus, an alternative research field is developing which claims to synthesize more stable artificial antibody-like receptors for the replacement of natural antibodies.

Here, a semi-covalent procedure is proposed to elaborate surface imprinted polymers for selective recognition of gonadotropin hormones.1,2 Briefly, this strategy consists of a combination of three methods, namely, (i) lithography, (ii) surface imprinting, and (iii) semi-covalent imprinting. Hard template silica beads were used as a mold to prepare a highly organized opal structure. On top of this, template proteins were immobilized. Later, the protein was derivatized with functional monomers. These functionalized template molecules were electrochemically cross-linked with an excess of cross-linking monomer. Removal of the silica mold creates a nanostructure containing molecular cavities on the surface. Such nanostructures are advantageous for non-restrictive diffusion of bulky proteins toward the respective molecular cavities.

We confirmed regular and hexagonal packing of silica beads, resulting in inverse opal surface imprinted molecular films, by Scanning Electron Microscope (SEM). The recognition of proteins by the nanostructured molecular imprinted polymer films was transduced with the help of capacitive impedimetry. The suitability of the synthetic receptor was further confirmed by measuring proteins in real blood serum samples.

References

[1] J. Kalecki, M. Cieplak, M. Dąbrowski, W. Lisowski, A. Kuhn, P. S. Sharma, ACS Sens.
2020, 5, 1, 118.

[2] M. Dabrowski, A. Zimińska, A., J. Kalecki, M. Cieplak, W. Lisowski, W. R. Maksym, S. Shao, F. D'Souza, A. Kuhn, P. S. Sharma, ACS Appl. Mater. Interfaces. 2019, 11, 9265.

Acknowledgements

The present research was financially supported by the Polish National Science Centre (Grant No. NCN 2017/25/B/ST4/01696 to P.S.S.).

Figure 1
A TiO2 Nanotube-Based Sensor for the Detection of Cyanide in Water
Authors: Subramanian Vaidyanathan , Tembo Prichard Mekani , Dhabarde Nikhil
Published: July 2021

Cyanide is an acutely toxic compound capable of reducing or eliminating oxygen utilization in living organisms on exposure. Natural and industrial processes contribute to the presence of cyanide in the environment. However, the concentrated nature of industrial-process-derived cyanide calls for greater attention. The ability to bind to other compounds makes cyanide capable of spreading to ground and surface waters more easily than other industrial contaminants. Cyanide concentrations in waste waters need monitoring to ensure that they are within permissible levels. Furthermore, cyanide is an essential reagent in some processes, and thus tracking of cyanide concentrations in the process line is essential. Real-time monitoring of cyanide concentrations calls for a robust and quick method for detection of cyanide concentrations in water. As such, this work focuses on the application of titanium dioxide (TiO2) nanotubes for the sensitive and selective electrochemical detection of cyanide in water. The TiO2 nanotubes were modified by the addition of iron (Fe) and sulfur (S) to the nanotube structures. Characterization of the prepared sensing electrode was carried out using X-ray diffraction and electron microscopy. Electrochemical sensing of the cyanide in water was performed using a three-electrode system with an Fe-S-TiO2 working electrode. Cyclic voltammetry was used to establish the sensing of the cyanide species as well as the response to cyanide concentration in water. Chronoamperometry was used to test the effect of interfering species as well as the sensor sensitivity, with an observed current response to a 0.1μM change in cyanide concentration. The sensor response indicated that an Fe-S-TiO2 sensing electrode could effectively be used for the sensing of cyanide concentrations lower than the recommended limits in water, and with good sensing electrode reusability.
Increased Vacancy Concentrations Improve Li+ Diffusion in Solid State Battery Electrolyte Li3OCl
Authors: Adelstein Nicole , Mehmedovic Zerina , Wei Vanessa , Grieder Andrew , Wood Brandon
Published: July 2021

All solid-state batteries are a promising new technology that can replace the current Li-ion batteries. The solid inorganic electrolyte offers advances in safety, durability, and volumetric and gravimetric energy density. The anti-perovskites lithium oxychloride (Li3OCl) and the hydroxychloride (Li3−xHxOCl) are promising solid electrolytes, though more optimization is required. Performance of these lithium rich anti-perovskites can be improved through understanding the diffusion mechanism through simulation. Here, we report the first comprehensive study varying Li+ concentrations in Li3OCl using ab-initio molecular dynamics simulations. The simulations accurately capture the complex interactions between Li+ vacancies (V’), with concentrations between 0.5-2%. Analysis of discretized local diffusion events in both space and time lend insight into the effect of vacancy concentration on the diffusion mechanism and the lowering of the activation energy barrier. The results reveal the critical interplay between lattice polarization, disorder, and correlated dynamics in promoting ionic conductivity in Li3OCl.
Surface-Modified Mxene Nanosheets to Enable Complete Utilization and Immobilization of Polysulfides in Lithium-Sulfur Batteries
Authors: Pai Rahul , Natu Varun , Sokol Maxim , Carey Michael , Barsoum Michel W. , Kalra Vibha
Published: July 2021

Lithium-Sulfur batteries are of great interest owing to sulfur's high theoretical capacity, low-cost and environmental benignity. However, the practicality of these batteries has been impeded due to the infamous “polysulfide-shuttle” effect. Although several research articles in the past decade have focused to mitigate this effect, capacity fade and low coulombic efficiency still prevail. 2D MXenes are early transition metal carbides known for their high metallic conductivity with tunable surface functionalities. MXenes with formula Mn+1XnTx are usually derived from the parental MAX phases by selectively etching the A layer (where M represents a transition metal, A represents the group 13 or 14 elements in the periodic table and X represents carbon or nitrogen, Tx stands for the surface terminations). Thus, the obtained MXenes possess a unique layered structure. After etching, the surface of MXenes is terminated with various functional groups such as hydroxyl (-OH), oxygen (-O), chlorine (-Cl), and fluorine (-F).

Rich surface polar sites in Ti3C2Tx enhance electrochemical performance via suppression of polysulfide shuttle. However, past synthesis procedures result in the development of hydrophilic MXene nanosheets unable to be coupled with hydrophobic sulfur. Herein, we propose a new design based on the functionalization of MXene nanosheets with an organic molecule for the effective deposition of sulfur nanoparticles on the surface. This strategy enables the dispersion of MXene sheets in sulfur dissolved solvents enabling the conformal deposition of sulfur on MXene sheets with negligible water in the composite. The metallic sheet-like conductivity (~103 S.cm-1) also aids in faster reaction kinetics during the conversion of polysulfides to Li2S, mitigating the shuttle effect. Consequently, the developed composite enables the efficient utilization of active surface sites to bind polysulfides and alleviate the shuttle effect. This novel cathode delivers a high initial reversible capacity of 1220 mAh·g-1 at 0.1 C and at 0.5C, these cathodes stabilize at 880mAh·g-1 after the first 5 cycles, 85% of which is retained post 500 cycles. Additionally, we developed cathodes with high sulfur loading of ~10.7 mg·cm-2 that delivers a stable areal capacity of ~7 mAh·cm-2 for 150 cycles. Moreover, these cathodes in a pouch cell configuration retained ~770 mAh·g-1 after ~200 cycles at 0.2C (85.5% retention). Ex-situ studies elucidated the nature of the LiPs–MXene interaction and the effect of surface functionalization towards improved performance

+RP and VN have equal contribution
The Role of Thiourea As an Electrolyte Additive in Lithium-Sulfur Batteries
Authors: Rafie Ayda , Kalra Vibha
Published: July 2021

Lithium-sulfur batteries offer five times more energy density compared to commercialized Lithium-ion batteries. Theoretical capacity in Li-S batteries reaches to ~1675 mAh/g making them a great candidate for next-generation batteries. Despite the advantages of Li-S batteries, they suffer from poor cycle life. The main challenge in achieving long-term cycling in Li-S batteries, known as polysulfide shuttling, is the dissolution and diffusion of highly soluble intermediate species, lithium polysulfides. Polysulfide shuttling results in a loss of active material and low efficiency of the Li-S battery. Moreover, Li2S, as the final discharge product, is an electronic and ionic insulator; consequently, activation of such material in the charge process of a Li-S battery becomes a challenge.

In the present work, thiourea is used as an additive in the ether-based electrolyte, commonly used in Li-S batteries. We integrated electrochemical characterization and testing with in-situ spectroscopy to understand the potential role of thiourea in enhancing battery cycle life. Specifically, we hypothesized that thiourea facilitates stable cycling via favorable interactions between its C=S and C-NH2 bonds and intermediate lithium polysulfides. To understand the reaction mechanism and to test our hypothesis, we carried out in situ FTIR experiments. Using in situ FTIR results, lithium polysulfide interaction can be studied through monitoring the changes in the vibrational mode of existing bonds. Our electrochemical results show that the Li-S battery with a very low thiourea concentration of 0.02 M, enabled an initial capacity of 800 mAh/g at C/2 rate. The discharge capacity stabilized at 700 mAh/g after 20 cycles and remained stable for up to 200 cycles (figure 1a), unlike the reference battery with no-additive electrolyte that remained stable for only 80 cycles (figure 1a inset). As a result of reduced polysulfide shuttling, the coulombic efficiency of the battery remained >98% throughout the cycling. The electrochemical results show that this additive plays a significant role in enhancing the cycling stability of Li-S batteries. Moreover, we found out that thiourea is electrochemically active in this voltage range. Based on the redox activity of this additive, we believe that thiourea can potentially be used as a redox mediator to activate Li2S in the charging process. To understand the potential effect of thiourea as a redox mediator, we synthesized Li2S/CNF nanofibers. The electrochemical testing of Li2S/CNF nanofibers shows a significant difference when thiourea is added to the conventional ether electrolyte. Based on the electrochemical results obtained, we believe that thiourea has two simultaneous effects on the performance of Li-S batteries. It can perform as an additive to bind Lithium polysulfides and reduce shuttling of these species. Moreover, as a redox mediator, it can activate Li2S in the charging process.

Figure 1
Free-Standing N-Doped Carbon Cathode for Li-S Battery
Authors: Yang Jeongwoo , Park Jae Hyun , Choi Won Yeong , Kim Dohyeun , Gim Hyeonseo , Lee Jae W
Published: July 2021

A free-standing carbon cathode is attractive in that it can increase the proportion of active material without any current collector, conductive material, and binder. This study introduces a free-standing carbon cathode derived from CO2 with very high porosity for lithium-sulfur battery. The free-standing carbon cathode, while having its very porous structure, shows very excellent elasticity, providing potential as a standalone electrode material in industry. In addition, in the process of making free-standing carbon through electrospinning of polyacrylonitrile (PAN) and NaBH4, the very rich N atoms, 19.38wt% of pyridinic N and 16.24% of pyrrolic-N, exist on the surface, which greatly improves the lithium sulfide adsorption ability and electrical conductivity. As a result, a capacity of 700 mAh g−1 is exhibited for 500 cycles at 0.2 C and 650 mAh g−1 is secured at 5C. Even with a very high active material loading amount of 6.11 mg cm−2, it maintained an areal capacity of 3.1 mAh cm−2 for 500 cycles at 0.2 C with the original free-standing form maintained.
Stripping and Plating Behavior of Sodium Metal in Carbonate and Ether Electrolytes
Authors: Sarkar Susmita , Reed Daniel , Carter Rachel E. , Love Corey T. , Mukherjee Partha P.
Published: July 2021

Sodium (Na) stripping is a subsurface process, where sodium (Na) metal is oxidized into Na ions and vice versa during the plating process of cell operation. The morphological/structural changes in the metal following the charge transfer during stripping can largely affect the subsequent plating process. While the reactions and kinetics at the electrode-electrolyte interface are being recognized as the primary factor in limiting the applicable capacity of Na metal anode, a unified framework incorporating a detailed electrochemical study of various electrolyte formulations is still lacking. In this work, we used different types of carbonates (PC, PC: FEC) and ether-based solvents (DME, diglyme, and TEGDME) with NaClO4 and NaPF6 salts to explore the compatibility of Na metal in different liquid electrolyte system. The microscopic images were compared in the context of Na deposition and pitting. The electrolyte composition has a distinctive effect on the evolution of the plated and stripped Na profile, and it was observed that TEGDME for both NaClO4 and NaPF6 salts has severe effects of sodium corrosion, evident by large cavities in the Na metal. Dramatic changes in growth morphological variables, particularly thickness, have a large impact on system viability, affecting the packaging, and thus, identifying the prevalence of the Na deposition or stripping is critically important. The dynamic changes in the voltage profile in a symmetric cell setup were also examined during extended cycles to understand the reaction and mass transport limitation in different electrolyte solvents. As the stripping and plating processes are indirect proof of cell aging, the observed behavior of Na metal-salt-solvent interaction in this work will help to highlight the potential for developing a better Na metal system with long term electrochemical performance.
A Critical Investigation of the Viability of Fast Charging of Lithium-Metal Batteries in Glyme-Ether Electrolytes
Authors: Dutta Arghya , Kubo Yoshimi
Published: July 2021

Widespread adoption of electric vehicles (EVs) largely depends on the development of efficient battery systems having high energy density with the capability of fast charging. In this regard, lithium (Li) metal-based batteries, such as Li-Oxygen and Li-Sulfur batteries, can provide much higher energy density compared to that of Li-ion batteries. However, low rate-capability of both Li-Oxygen and Li-Sulfur cells hinders their practical utilizations. It has been found that transport limitations in the electrolyte play a major role in affecting the rate-capability of the cells. Therefore, identifying a suitable electrolyte with high ionic conductivity is an essential requirement to improve the rate-capability of these batteries. Additionally, a desired electrolyte must also be stable toward the electrode processes in the cell. Glyme-ether based electrolytes, in these instances, are a preferred class of electrolytes for both Li-Oxygen and Li-Sulfur batteries due to their acceptable compatibility with Li metal as well as with the porous carbon electrodes. Nevertheless, the length of the glyme-ethers dramatically affects the ionic conductivities of the electrolytes and decides the rate-capability of the battery. Therefore, in this work we have investigated the viability of fast Li-plating in different glyme-ether electrolytes and critically analyzed the effects of ion-transport and also assessed the relative stabilities of the electrolytes during Li stripping/plating processes.

The present study involves investigation of Li stripping/plating in six different electrolytes using three glyme-ethers, diglyme (G2), triglyme (G3) and tetraglyme (G4), as the electrolyte solvents with lithium nitrate (LiNO3) or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the Li salts (1 M) and lithium bromide (LiBr) as an additive (0.05 M). It has been found that the ionic conductivity of the electrolyte increases as the glyme becomes smaller or highly associated LiNO3 is replaced with LiTFSI. As a result, both smaller glymes and LiTFSI help to achieve Li-plating at faster rates. However, unfortunately, stability of Li-plating in terms of Coulombic efficiency and overall cycle-life decreases in smaller glymes or in LiTFSI as the Li salt and detailed investigations reveal formation of unstable SEI to be responsible for lower stability of Li-plating in these electrolytes. Our results show that the consequences of increasing the ionic conductivity of the electrolyte by simply changing the glyme-ether solvent in Li-metal batteries are quite complex and warrant careful consideration of their relative stabilities with the electrode. All the results, in depth analyses and future perspectives of this work will be discussed during the presentation.
Testing with Thin Lithium Anode and Practical Capacities for Fast Evaluation of Polymer Electrolytes for Solid-State Batteries
Authors: Sahore Ritu , Du Zhijia , Chen Xi Chelsea , Westover Andrew S , Dudney Nancy
Published: July 2021

Lithium metal solid-state batteries can reach greater than 400 Wh/kg energy density compared to ~300 Wh/kg of conventional lithium-ion batteries. However, the amount of inactive material needs to be significantly reduced, and active material loading maximized. For example, the lithium metal anode needs to be <10 µm, the solid electrolyte separator layer needs to be <20 µm, and the cathode capacity >4 mAh/cm2. Several new inorganic and polymeric electrolytes have been discovered in the past decade. Nevertheless, the integration and testing of these novel candidate materials into functioning cells with the electrode loadings and dimensions required to meet the cell-level energy density goals have been limited. For example, typically, hundreds of microns thick lithium foils are used, which can hide any lithium losses at the anode due to reactions or physical isolation and lead to artificially long cycle life. The amount of lithium cycled is also typically too low (<1 mAh/cm2) compared to the desired 4 mAh/cm2 in both symmetric and full-cell tests. Such testing makes it difficult to gauge the progress of the field in reaching practical energy density goals. We argue that testing new materials solutions at full-cell level with practical electrode loading/dimensions can help understand their limitations quicker and progress faster towards reaching the cell-level energy density goal of >400 Wh/kg.

In this work, using two polymer electrolytes (a “dry” and a gel-type), we present several examples that demonstrate the impact on solid-state battery performance as electrode thicknesses/loadings and cycling capacities are shifted towards practical values. First, using thermally-evaporated ultra-thin (1-10 µm) lithium metal anodes, we quantified the lithium losses during cycling at the lithium/polymer-electrolyte interface. Our results show severe lithium losses or ultra-low coulombic efficiency of a common gel-polymer electrolyte leading to complete consumption of the lithium reservoir within a few cycles. Second, we present examples that highlight the challenges of increasing cycling capacities towards practical values. These examples underscore the need to test novel materials solutions directly with such practical capacities, either in full-cell or symmetric-cell formats, to accelerate the materials development endeavors.
Mesoscale Interfacial Interactions in All-Solid-State Lithium Batteries
Authors: Vishnugopi Bairav Sabarish , Mukherjee Partha P.
Published: July 2021

All-solid-state batteries comprising of a lithium metal anode are promising next-generation energy storage systems, capable of providing enhanced safety and delivering high power and energy densities. Despite the inherent mechanical rigidity of solid electrolytes, the irregular nature of electrodeposition at the metal anode remains unresolved and thereby necessitates a detailed description of the mechanisms underlying the interfacial instability. The morphological evolution of the metal anode is influenced by various factors including the mechanical properties of lithium and solid electrolyte, presence of interfacial roughness, grain boundaries in the solid electrolyte microstructure and external operating conditions. In this work, the fundamental electrochemical-mechanical interactions governing the electrodeposition stability at the solid-solid interface, especially the role of grain boundaries will be examined in detail.
Polymer Templating Method for the Formation of Hierarchically Porous Nitrogen-Rich Tin-Carbon Composite Anodes
Authors: Weeks Jason Alexander
Published: July 2021

This study aims to provide a new platform for the fabrication of metal-carbon composites. Herein we show that the high density crosslinking of a polymer can be used to homogenously trap metal nanoparticles and other components. In this setting, we utilized the cross-linking of poly(maleic anhydride-at 1-octadecene) [PMAO] with ethylene glycol to trap metal nanoparticles and carbon nitride (C3N4) within the polymeric structure. During inert, high-temperature pyrolysis, the polymer acts as a soft-template and prevents agglomeration of metallic tin during the synthesis. Inspired by the work of Tang et al. the carbon nitride is employed to act as a nitrogen dopant source and textural template for the final product. Through an analysis variable experimental parameter, we have shown that this method provides an avenue for the tunable fabrication of nitrogen-rich porous composites. To demonstrate the practicality of this synthetic method, composites with a variety of different nitrogen moieties and textural compositions were electrochemically analyzed. The resulting composites were then used as a platform to demonstrate not only the tunability of the synthetic method but also an example of how much these effects drastically dictate the electrochemistry of the system. Of the samples analyzed it was shown that a urea based composite demonstrated the best electrochemistry touting high rate capability, stable cycling, and high coulombic efficiency (CE).

The results of long-term performance testing reveal the excellent electrochemical properties of the U-Sn-CN composite, supplying an initial capacity of ~ 600 mAh g–1 and 82.0 % capacity retention over 400 cycles at a high current density of 1 A g–1 (1C) with an average CE of 99.8 %. Lower current density studies [500 mA g-1 (C/2)] have shown the material to have an initial capacity of ~ 640 mAh g–1 with 86.0 % capacity retention over 400 cycles. Electrochemical and post-mortem analysis of this composite material suggest the performance properties can be attributed to the unique nitrogen-doped carbon framework, which is able to buffer the large volumetric expansion of the tin due to its disordered flexible nature whilst contributing to the overall capacity of the composite from its high degree of nitrogen doping (~11.9 at %).

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Optimization of Magnesium-Doped Lithium Metal Anode for Lithium Metal Batteries: Simulation and Experiment
Authors: Gao Peiyuan , Wu Haiping , Zhang Xianhui , Jia Hao , Kim Ju-Myung , Niu Chaojiang , Xu Zhijie , Zhang Ji-Guang , Xu Wu
Published: July 2021

To further improve the energy density of the current lithium ion batteries, tremendous effort has been made on the development of anode materials with higher capacities than the widely commercialized graphite. Lithium metal is considered as the most attractive anode candidate for lithium batteries because of its ultrahigh specific capacity (3860 mAh g-1) and extremely low redox potential (-3.040 V vs. standard hydrogen electrode). While the uncontrolled lithium dendrite growth and the interfacial instability, leading to low Coulombic efficiency, are two big problems for pure lithium metal anodes. Lithium-magnesium alloy has been considered as a potential alternative anode material. There have been some studies of magnesium amount on lithium-magnesium alloy anode with a wide range. It is found that even a marginal amount of magnesium can improve the battery performance. However, the optimum content of magnesium in lithium-magnesium alloy anode and the mechanism on cell performance are still not well understood. Quantum chemistry and molecular dynamics simulation methods have been widely used in advanced electrode materials design to accelerate the material discovery and development. Computational and experimental approaches are combined to optimize the amount of magnesium in lithium-magnesium alloy anode materials and investigate the cell performance. This work focuses on lithium-magnesium alloy with limited magnesium amount. The density functional theory calculation is employed to investigate the effect of doping magnesium amount in lithium-magnesium alloy anode. Simulation results show that the additional magnesium atom in lithium-magnesium alloy can control the plating/stripping of lithium atoms on the alloy anode surface. Moreover, an optimum ratio of magnesium in lithium-magnesium alloy is found when calculating the absorption energy of lithium atom on lithium-magnesium alloy surface. Electrochemical experiments further demonstrate that the alloy anode material with the optimal ratio of magnesium exhibits the best cycling stability in lithium metal batteries with high nickel layered oxide cathode. This work provides an effective approach to identify optimal alloying-type lithium metal anodes for improving long-term cycling stability of high-energy-density lithium metal batteries. More details will be discussed at the presentation.
Advanced Electrolyte Stabilizing Ultrahigh-Nickel Layered Oxide Cathode in High-Voltage Lithium Metal Batteries
Authors: Zhang Xianhui , Zou Lianfeng , Cui Zehao , Jia Hao , Engelhard Mark H. , Matthews Bethany E. , Cao Xia , Xie Qiang , Wang Chongmin , Manthiram Arumugam , Zhang Ji-Guang , Xu Wu
Published: July 2021

To achieve batteries with high specific energy, long cycle life and low cost, the promising approach is to use lithium (Li) metal as anode and nickel (Ni)-rich/cobalt (Co)-less layered oxides as cathode. When the Ni content in the cathode is increased to an ultrahigh level (Ni ≥ 0.9), more specific energy can be obtained from the capacity contribution and high redox potential of Ni3+/Ni4+. Therefore, high-voltage Li metal batteries with ultrahigh-Ni layered oxide cathodes will offer a great opportunity in boosting the energy density of battery systems for applications in electrical vehicles. However, increasing Ni content intrinsically faces a dilemma between specific capacity and electrochemical cyclability for the cathode materials because of the aggressive side reactions of electrolyte on the highly reactive Ni surface. Here, we report an advanced electrolyte to enable high stability with both the reactive Li metal anode and an ultrahigh-Ni cathode LiNi0.94Co0.06O2 (NC), via the in-situ formation of a robust and conductive Li/electrolyte interphase and a protective and stable cathode/electrolyte interphase. Thus, the Li||NC cells with the advanced electrolyte can deliver a high discharge capacity of about 210 mAh g−1 and an excellent capacity retention of 81.4 % after 500 cycles at 25 °C in the voltage range of 2.8 - 4.4 V at 1C cycling rate (1.5 mA cm-2), which significantly outperform the cells using the conventional LiPF6-based electrolyte. This work provides a viable path to the successful application of ultrahigh-Ni cathode in high energy-density Li metal batteries. More detailed information will be given at the presentation.
Binder Free Three-Dimensional Hybrid Cathode for Stable and High-Performance Li-S Batteries
Authors: Adhikari Pashupati Raj , Bhoyate Sanket , Choi Wonbong
Published: July 2021

Lithium-sulfur batteries (LSBs) represent a promising energy storage technology with a potential for next-generation high-energy storage systems due to their high specific capacity, abundant resources, low cost, non-toxicity, and environmentally friendly characteristics. However, due to many critical limitations such as insulating nature of elemental sulfur, poor lithium polysulfide (LiPS) conversion kinetics, polysulfide shuttle effect resulting in capacity fading, and low cyclic stability, commercialization of LSBs are far from realization. One of the most essential strategy to mitigate the issues with LSBs is to prevent polysulfide shuttling thereby maximizing the sulfur utilization and enhance the overall Li-S battery performance. In this work, we develop a binder free three-dimensional hybrid cathode for Li-S battery using multiwall carbon nanotubes (CNTs) and molybdenum sulfide (MoS2) as a catalyst, collectively enhancing LiPS conversion and ion transport ability and hence increased energy density, both gravimetric and volumetric. Different uniform mixtures of CNTs, MoS2, and conductive carbon black are prepared and loaded with high sulfur loading of ~6 mg cm-2. Various electrochemical performance parameters influencing cathode performance with respect to both gravimetric and volumetric energy densities are studied. Parameters that help improve the overall battery performance are identified and discussed.
Development of Si/C6 Negative Electrode for High Capacity Lithium-Sulfur Batteries
Authors: Tsunoda Uran , Ushioda Yusuke , Machida Kazuki , Seki Shiro
Published: July 2021

Recently, lithium-sulfur batteries are attracting attention as large-capacity energy storage devices for renewable energy. Lithium-sulfur battery uses elemental sulfur (S8) as positive electrode and Li metal as the negative electrode, respectively. Although large theoretical capacity (1,672 mAhg-1) of the sulfur active material is expected as advantage, formation of Li dendrites at the Li metal surface during charge process is concerned as serious problem. In this study, we applied a negative electrode with Si to suppress the precipitation of Li dendrites. The theoretical capacity of Si is extremely high at 4,200 mAhg-1 and high energy density can be expected. However, Si has low cycle performance owing to their volume changes with Li+ insertion and desorption. In this study, several cells ([Li | 1M-LiFSI EC/DEC(=3/7) | x wt%-Si/C6] ) using nano-Si mixed electrodes with C6 ( x wt%-Si/C6 (x=5,10,25,50) ) were prepared and evaluated.

As example, showing how the 5wt%-Si/C6 electrode is fabricated. C6:Si:Acetylene Black:PVdF was mixed into the NMP solvent at a weight ratio of 81:4:7:8. The mixed slurry was applied onto copper foil and dried at 353 K. The 5wt%-Si/C6 electrode was punched to φ 16 mm and pressed with a uniaxial force. [Li| 1M-LiFSI EC/DEC(=3/7) | x wt%-Si/C6] cells were prepared and investigated by charge-discharge test at 303 K.

Fig. 1 shows the charge-discharge profiles at the first cycle of the [Li| 1M-LiFSI EC/DEC(=3/7) |x wt%-Si/C6] (x=5,10,25,50) cells (a) and the relationship between the number of cycles and discharge capacity (b) . The initial discharge capacity was higher than the theoretical capacity of C6 (ca. 360 mAhg-1). However, remarkable decrease in discharge capacity is confirmed in accordance with an increase in the mixing amount of Si. Miniaturization might be occurred due to the volume change of Si during the charge-discharge reaction. As a result, the reaction at the electrode/electrolyte interface should be degraded. Irreversible reactions might be occurred after 2nd cycle. In addition, the lowest discharge capacity was obtained at 10wt%. As a result, isolation of active material was also suggested. Therefore, it is necessary to consider improving the cycle characteristics by the use of additives and improvement of the negative electrode itself. In the presentation, we will report for improvement methods of charge-discharge properties, such as new binder and composites with electric conductive additives.

Figure 1