bluuebunny/crossref_metadata_2025 huggingface dataset:
3D-Printed Molecularly Imprinted Polymers: Advanced Molecular Recognition Interfaces for Chem/Bio Sensors
Authors: Mizaikoff Boris
Published: December 2024

Molecularly imprinted polymers (MIPs) are known for their stability and specificity serving as biomimetic molecular recognition motif in applications including but not limited to diagnostics, drug delivery, and environmental monitoring. Despite their straightforward synthesis and robustness, the commercial scale-up of MIPs remains challenging, in particular concerning homogeneity and reproducibility of the material and structure, which are both critical for practical applications.

To overcome these challenges, we have developed an innovative strategy synergistically combining LCD-based 3D printing with MIP technology, which enables a yet unprecedented level of manufacturing precision and structural reproducibility. The integration of photo-curing-based 3D-printing with polymerization-induced phase separation constitutes a key advancement facilitating the scalable fabrication of complex macroscopic polymer structures. In addition, the inherent porosity of the material can be precisely controlled at the sub-micrometer level, while at the same time tuning the macro-porosity of the geometric structure via digital design.

This hybridization of techniques marks a new era for MIPs facilitating the production of materials with precison-engineered properties that meet the demanding requirements of a wide variety of applications. Resulting, a robust and scalable approach has been developed that not only improves the reproducibility of MIPs, but also expands their applicability and promises a rapid transition from laboratory innovation to commercial reality. This process is particularly suitable for coating and structuring molecular chem/bio sensing architectures at the surface of electrodes, waveguides and other transducers establishing next-generation biomimetic sensing schemes.

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Rapid Detection of Trace Levels of Perfluorooctanoic Acid Using Photothermal Cantilever Deflection Spectroscopy
Authors: Zhao Yaoli , Leatt Kyle , Krishna Murthy Prabakar , Thundat Thomas
Published: December 2024

Real-time detection of chemical contaminants in the environment using portable, low-cost sensors with high selectivity, sensitivity, reproducibility, and wide dynamic range is challenging because of the complex nature of analytes and sample matrices. The challenge is exacerbated when the targeted chemical contaminants appear at trace levels. There is currently an urgent need to develop chemical sensors that can selectively and sensitively detect emerging contaminants, such as per- and polyfluoroalkyl substances (PFAS) in various environmental matrices. We have developed a portable sensor system based on standoff detection. In this method, a surface containing perfluorooctanoic acid (PFOA) is irradiated with infrared radiation from a tunable source, and the scattered radiation is collected and detected with a bimatetial cantilever. The differential deflection of the cantilever as a function of irradiation wavelength shows the IR absorption spectrum of the PFOA. The experimental results show the detection of PFAS with high selectivity and with ppb sensitivity and the developed technique can detect the trace levels of contaminants in less than 5 min.
Deep Microfabrication of Silica Glass Using Atmospheric Gas-Phase Catalyst Etching for Sensing Applications
Authors: Sano Kohei , Ono Yoshitaka , Yasuda Kohei , Tobinaga Ryosuke , Imamura Yutaka , Hayashi Yasuo , Yanagitani Takahiko
Published: December 2024

Deep microfabrication processes such as the Bosch process have dramatically improved the performance of Si-MEMS devices. In contrast to Si, SiO2 is suitable for optical analysis devices because of its high transparency over a wide range and chemical durability. In recent years, micro-total analysis systems using glass-type microfluidics or microwell arrays have attracted attention in the field of biotechnology. Anisotropic microstructures on silica glass substrates are generally fabricated via reactive ion etching (RIE). However, high-power ion energy is required to fabricate deep microstructures because of the high chemical and plasma durability of SiO2. Therefore, the fabrication of vertical deep microstructures on SiO2 has been a longstanding problem because a hard mask material is etched simultaneously during RIE. We focused on surface treatment with HF gas, which enables dry etching of SiO2 without using a plasma source1,2. The chemical reaction between HF gas and SiO2 can be expressed as follows:

SiO2 + 4HF → SiF4 + 2H2O.

However, the etching reaction of SiO2 by HF molecules is extremely slow1. Therefore, H2O or alcohol, which form hydrogen bonds with HF molecules, are added as a catalyst in the etching of SiO2 with HF gas2,3.

This study proposed the deep microfabrication of SiO2 by HF gas etching using a photoresist as a catalyst that allows micro-scale patterning on the substrate4. The hydrophilic functional groups in the catalyst formed hydrogen bonds with the HF molecules at the interface with SiO2. Therefore, the etching reaction by HF gas occurs only at the interface between SiO2 and the catalyst. This selective etching reaction enables deep microfabrication on SiO2 without the use of a plasma source or hard mask materials. The microstructures fabricated via the HF gas-phase catalyst etching were characterized by high verticality and smooth sidewall surfaces, as shown in Fig.1. This simple microfabrication process could improve the sensing performance and the mass production of SiO2-based microfluidic devices and microwells.

REFERENCES

Habuka, H.; Otsuka, T. Reaction of Hydrogen Fluoride Gas at High Temperatures with Silicon Oxide Film and Silicon Surface. J. Appl. Phys., 1998, 37, 6123–6127.

Holmes, P. J.; Snell, J. E. A Vapor Etching Technique for the Photolithography of Silicon Dioxide. Microelectronics and Reliability, 1966, 5, 337–341.

Jang, W. I.; Choi, C.A.; Lee, M.L.; Jun, C.H.; Kim, Y.T. Fabrication of MEMS Devices by Using Anhydrous HF Gas-Phase Etching with Alcoholic Vapor. Micromech. Microeng., 2002, 12, 297–306.

Sano, K.-H.; Ono, Y.; Tobinaga, R.; Imamura, Y.; Hayashi, Y.; Yanagitani, T. (in press). Atmospheric Gas-phase Catalyst Etching of SiO2 for Deep Microfabrication Using HF Gas and Patterned Photoresist. ACS Appl. Mater. Interfaces, Apr. 2024.

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(Sensor Division Early Career Award Address) Advancing Hydrogen Technologies with Real-Time Ion Sensing and Tracking
Authors: Dong Dongmei
Published: December 2024

As we strive for a sustainable future through a green hydrogen economy, it is essential to understand the degradation mechanisms of hydrogen-focused electrochemical devices, such as proton exchange membrane (PEM) fuel cells and water electrolysis systems. Our research delves into current accelerated stress tests and the resulting degradation phenomena through associated comprehensive analyses that include electrochemical, spectroscopic, tomographic, and microscopic techniques, along with detailed examinations of electrode, membrane, and interface structures. Current studies often rely on sophisticated, stationary laboratory equipment to uncover these degradation features under dynamic operations. However, for practical applications like hydrogen-powered electric vehicles, there is a critical need for a portable, low-cost, and user-friendly diagnostic tool.

Given the crucial role of ion exchange and transport, nanoparticles and polymers and the potential for dissolution, monitoring, and tracking ion traces over time can provide critical insights into the behaviors within PEM-based fuel cells and water electrolysis systems. Our recent work focuses on creating electrochemical and transistor-based ion sensors integrated into a circuit chip for real-time, in-situ monitoring of system health and degradation. This effort not only aims to improve real-time diagnostics but also provides guidelines for developing suitable accelerated stress test protocols to assess system durability and for designing materials that can withstand long-term use.
MOF Assisted Ion-Conductive Nanocomposite Hydrogel Based Robust Strain Sensor
Authors: Rahman MD Sazzadur , Rahman Muhammad Toyabur , Kim Seonghwan
Published: December 2024

Soft, flexible, and stretchable materials with exceptional toughness and adhesion properties hold great potential for robust strain sensor development across various applications. An ion-conductive hydrogel, consisting of polyacrylamide (PAM) and 2-hydroxyethyl acrylate (HEA), LiCl incorporates via imidazole-based metal-organic framework (MOF) nanoparticles to introduce multifunctionality and enhance mechanical properties, including stretchability, toughness, energy dissipation, and hysteresis loop, for use as wearable strain sensors. The zeolite imidazolate frameworks-8 (ZIF-8) reinforced nanocomposite hydrogels exhibit high fracture elongation up to 800%, fracture strength up to 110 kPa, fracture toughness up to 0.45 MJm-3, and minimal hysteresis as low as 2.6%. Additionally, the hydrogels adhere well to various surfaces, including steel, glass, silicone rubbers, aluminum, and nitrile rubbers, and demonstrate resilience in freezing temperatures down to -20°C. The synergy of electrostatic interactions between the AM-HEA polymer chain and nanoporous ZIF-8 enhances the mechanical properties, while the abundant hydrogen bonds originating from the polarized surface of ZIF-8 also introduce multifunctionality to the nanocomposite hydrogel. These properties enable the hydrogels to act as strain sensors with a high sensitivity gauge factor of ~3.00, along with fast response and recovery times of 280 ms and 330 ms respectively. The versatile multifunctionality of the ZIF-8 reinforced nanocomposite ionic hydrogels prepared herein could offer a novel approach to designing and fabricating advanced all-round strain sensors for promising applications in biomedical fields, particularly in health assessment and human motion monitoring.
Development of Electrochemical Sensors for Dissolved Inorganic Nitrogen Detection at Release Sites into the Great Barrier Reef
Authors: Tan Jing Fang , Chandra Shaneel , Anastasi Amie
Published: December 2024

The accumulation of dissolved inorganic nitrogen (DIN); nitrate, nitrite and ammonium species of anthropogenic origin within water bodies remains a key environmental challenge. It causes detrimental effects to aquatic ecosystems and human health. Regular monitoring of nutrient levels in vulnerable sites is therefore the first crucial step in managing water quality. Sensor technologies that work in real time, on-site, reliably and frequently with immediate data-transfer to end-users are necessary for effective monitoring. One ideal detection system is based on electrochemical sensors. To this end, a low-cost, easy-to-use DIN sensor device was developed using modified screen-printed electrodes. Sample delivery and extrication was possible via an automated Arduino-pump attachment, with scheduled readings and imbedded algorithms for data processing. Additionally, data captured by the sensor was capable of being wirelessly transferred to a separate CPU unit. The screen-printed electrodes were immobilized with nanomaterials specific to the target analyte, and the solid-state reference electrodes were also modified to compensate for matrix effects, particularly from chloride. Nitrate and ammonia electrodes were based on ion-selective membranes; nitrate ionophores and nonactin respectively. Nitrite electrodes were immobilized with gold nanoparticles, nickel oxide nanoparticles, and electrochemically deposited with reduced graphene oxide. To determine operational success in the field, the automated sensor systems were tested on water samples from waterways draining into the Great Barrier Reef. Inter-laboratory comparisons were undertaken for quality control. This research exhibits promising applications for more affordable, miniaturized, real-time field sensors with strong potential for improving water quality and management.
(Digital Presentation) An Integrated Platform for Immune Profiling and Cytokine Monitoring
Authors: Kang Xuejia , Zhou Lang , Ma Chao , Wang Chuanyu , Wu Shuai , Wu Siqi , Chen Weiqiang , Rampauram Jayachandra Babu , Chen Pengyu
Published: December 2024

In the realm of cancer immunotherapy, the pivotal role of immune cells in driving efficacy, and the delicate balance maintained by cytokines between efficacy and potentially life-threatening side effects, cannot be overstated. Hence, precise in situ immune profiling and close scrutiny of critical cytokines are imperative for assessing the features associated with immunotherapeutic interventions. Unfortunately, existing in vitro assessment methods suffer from drawbacks such as being endpoint, time-intensive, and demanding large sample volumes.

To address these limitations, we present an innovative solution: an integrated real-time 3D vascularized blood-brain barrier (BBB) chip. This cutting-edge platform faithfully replicates the BBB environment infiltrated by immune T cells while simultaneously enabling the monitoring of immune profiling. Crucially, it facilitates the real-time detection of cytokines during CAR T cell interactions with various cell types. This comprehensive monitoring encompasses crucial aspects such as T cell and monocyte migration, cancer cell recognition, immune cell activation, and cytokine and neurotransmitter dynamics. Furthermore, the chip allows for the evaluation of the dynamics of therapeutics aimed at managing side effects associated with immunotherapy.

A key highlight of our approach is the ability to detect cytokines directly within the biological milieu. This method exhibits an impressive detection range spanning from 1 to 10,000 pg/mL, requiring only a minimal sample volume of 4 μL. The innovative sensing mechanism utilizes pillar microarrays, where anti-cytokine capture antibodies (CAbs) immobilized as the primary layer efficiently capture cytokines. Paired detection antibodies (DAbs) then facilitate signal detection, enabling simultaneous detection of multiple cytokines within small sample sizes through parallel processing.

By providing a means to effectively monitor the dynamics of immune therapy-induced factor release without perturbing the cancer microenvironment, our integrated chip empowers researchers to delve deeper into the intricacies of immunotherapy while enhancing its safety profile. This advancement holds significant promise for improving the outcomes of cancer treatment, ushering in a new era of precision and efficacy in cancer immunotherapy.
Effect of Direct Current and Periodic Polarization on Differential Electrolytic Potentiometric Signal Produced By Carbon Nanotube Electrode
Authors: Osman Abdalghaffar Mohammad
Published: December 2024

In differential electrolytic potentiometry (DEP), a pair of identical indicator electrodes is polarized using either a very small, heavily stabilized direct current (DC) or a periodic square waveform (SW) of constant amplitude. The square wave can be biased or bias-free. In this study, carbon nanotube-modified silver electrodes, CNT-Ag, were used as the DEP indicating system with all types of polarization. This was done to investigate how the polarization mode affects the signal intensity, shape, position, and amplification. The method was applied to analyze various analytes including ascorbic acid, Fluoroquinolone, cyanide, and chloride using normal titrimetric and sequential injection analysis (SIA) methods. Many of the findings showed that raising the polarizing direct current density (µA/cm2) boosts the DEP peak until reaching a certain point, after which the peaks begin to widen and the position of the peak center shifts. Similar changes were observed when increasing the percentage bias of the square waveform used to polarize the CNT-Ag indicator electrodes. The free-biased square waveform led to the least improvement in peak intensity. As the percentage bias increased, the peak intensity improved up to a certain level. However, beyond that point, all peaks began to broaden without further enhancement in intensity. In all cases, periodic polarization of electrodes produced a much greater enhancement in peak intensities compared to direct current polarization. With square-wave polarization, the ongoing reversal of polarity prevents the accumulation of films on the electrodes, speeds up the response, and substantially reduces electrode fouling and deactivation.

Furthermore, aside from the advantages of the periodic polarization, the CNT-Ag electrode, fabricated through chemical vapor deposition with aligned and well-structured CNTs, contributes to boosting the DEP peak intensity by promoting heterogeneous electron transfer. This process facilitates fast equilibrium, leading to precise and reproducible results.

Figure 1
Monolithic Integration of Lead Chalcogenide Thin Films on Silicon Substrates via Surface Morphology Engineering for Low-Cost Mid-IR Photodetector Applications
Authors: Park Jeung Hun
Published: December 2024

In this study, we assess the impact of surface modification techniques on the signal-to-noise ratio and opto-electrical properties of lead chalcogenide thin films grown on silicon substrates using chemical bath deposition (CBD). Our research supports the development of cost-effective mid-wavelength infrared (mid-IR) photodetectors. We focus on the adhesion stability and physical properties of lead chalcogenide films on Si substrates treated with surface oxidation and plasma. We employ atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and current-voltage (I-V) measurements to characterize these films.
Bay-Region, Nitrogen Functionalized Perylene Diimides for Printed Electronic Sensors
Authors: Welch Gregory Charles
Published: December 2024

The chemistry of organic conjugated materials is rich. Chemical structures can be infinity tuned to tailor optical, electronic, and physical properties. With an ability to transport electrical charge, such materials have found widespread use in electronic devices ranging from solar cells to sensors, so called ‘organic electronics. As organic electronic technologies move towards commercialization there becomes a focus on cost and sustainably. Perylene diimide (PDI) is a classic organic dye that has been well manipulated and studied in organic electronics and championed as chemically versatile, high-performance, and accessible (i.e. low-cost). While many electronic devices featuring PDI as an active electronic component have been engineered to achieved high performance, sustainably (i.e. greenness) has often been overlooked. Our research team at the university of Calgary is a member of the Canadian NSERC Green Electronics Network (GreEN) developing new materials and processes for sustainable organic electronic devices. This presentation will showcase two new PDI dyes, modified with active pyrrole or amine functional groups to produce electronically active, large area, green solvent roll-coated films. The materials design, chemistry, properties, and utility as electronic amine sensors, fully roll coated, will be discussed.

References:

Flexible dual-action colorimetric-electronic amine sensors based on N-annulated perylene diimide dyes. RSC Sensors and Diagnostics. Early View. 10.1039/D4SD00004H

Organic heterojunction charge-transfer chemical sensors. Journal of Materials Chemistry C. 2024. 12, 5083-5087.

An air-stable n-type bay-and-headland substituted bis-cyano N-H functionalized perylene diimide for printed electronics. Journal of Materials Chemistry C. 2021. 9, 13630-13634.

Acid dyeing for green solvent processing of solvent resistant semiconducting organic thin films. Materials Horizons. 2020. 7, 2959-2969.
(Invited) Engineering Pore Structure of Hard Carbon Anode Materials for High-Power Potassium-Ion Hybrid Capacitors
Authors: Hwang Jongkook
Published: December 2024

Potassium ion hybrid supercapacitors (PIHCs) have received great attention because of the low redox potential of K/K+ as well as the wide availability and low cost of potassium resources. However, the development of high power PIHCs has been largely limited by the sluggish K+ storage kinetics in battery-type carbon anode materials. Among the various strategies to improve the electrochemical performance of carbon anodes, pore structure engineering has been emphasized as an effective solution. Although several previous studies have reported the relationship between pore structure and K+ storage behavior, there is no consensus on the exact role of pores of different sizes. This is due to (i) the difficulties in preparing suitable model carbon materials with controlled porestructures, and (ii) the limited understanding of the role of pore structure in capacitive-controlled and diffusion-controlled K+ storage, respectively.

In this presentation, I will showcase the latest advancements from our research group in understanding the influence of pore structures on the K+ storage behaviors of hard carbon anode materials. We have developed carbon materials with controlled pore sizes (namely, micropore-dominated, ultramicropore/mesopore-mixed, and mesopore-dominated), and revealed a notable positive correlation between ultramicropore volume and enhanced capacitive K+ capacity. Additionally, our research team has successfully synthesized mesoporous carbon spheres with controlled mesopore openings. We found that prominently exposed mesopores significantly enhance the capacitive K+ storage capacity. This enhanced capacitive contribution in turn contributes to increased power densities in PIHC devices. These insights are pivotal in guiding the strategic design of pore structures to maximize capacitive K+ storage in carbon anode materials, thus propelling the development of high-power PIHCs.
Solvent-Confined Van Der Waals Gap Engineering to Improve Energy Storage in a 2D Layered Supercapacitor
Authors: Shim Jaehyung , Lee Chul-Ho
Published: December 2024

Despite the rapidly growing demand for high-performance and eco-friendly supercapacitors in the pursuit of sustainable energy storage, achieving both high volumetric energy density and ultrafast charging remains a significant challenge. Two-dimensional layered materials (2DLM) have emerged as promising electrode materials due to their ability to form highly networked nanochannels. Understanding the transport behavior of ions within these nanochannels is crucial for efficient energy storage. Recent advancements have shown promise in creating nanochannels that enhance ion transport and storage. However, controlling the properties of nanochannels has been challenging due to their nanoscale size and limited choice of solvents primarily water.

Here, we propose a manufacturing method of 2DLM films that confines various solvents within the van der Waals gap, allowing for adjustable thickness from nano to micro dimensions. The confined solvents serve as nanofluidic channels, improving ion transport and achieving high-density energy storage. Our ethanol-confined films demonstrate a gravimetric capacitance of 302 F g-1 and a volumetric capacitance of 1033 F cm-3, measured at a scan rate of 100 mV s-1, which is twice as high as water-confined films. By selectively controlling the nanochannels, we can regulate the channel distance and density of the film, effectively enhancing the electrode surface potential and enabling ultrafast ion transport. This demonstration offers valuable insights into the design of 2DLM films for energy storage and conversion applications.
Mechanisms and Applications of Electrochemical CO2 Capture Utilizing Activated Carbon Supercapacitors
Authors: Ferris Alan , Ding Ran , Dawlaty Jahan M , Rodriguez Lopez Joaquin , Augustyn Veronica
Published: December 2024

Fundamental understanding of high energy efficiency and selective CO2 adsorption mechanisms could lead to improvements in direct-air CO2 capture technology. Supercapacitive swing adsorption is a high energy efficiency electrochemical method to reversibly capture CO2 under an applied bias on activated carbon electrodes, but its mechanism remains unclear. Here, we examine the mechanisms behind supercapacitive swing adsorption using both planar gold electrodes to probe the electric double layer response and activated carbon electrodes in a flow cell configuration to probe the effect of porosity and confinement. The double layer capacitance of polycrystalline gold electrodes decreased in a CO2 saturated electrolyte as compared to argon. We attribute this phenomenon to the presence of CO2 and/or bicarbonate in the electric double layer under applied bias. To determine the effect of porosity and confinement on supercapacitive swing adsorption, we developed a flow cell with symmetrical activated carbon electrodes. Upon comparing various commercially available activated carbons, we found that high surface area was a leading factor for increased CO2 adsorption capacity. We further varied the CO2 flow rate, charge protocol, gas composition, and electrode composition to determine which factors led to optimum CO2 adsorption capacity and energy efficiency.
Cobalt-Free Layered Nickel Oxides with Antisite Defects for Long-Lived Lithium-Ion Batteries
Authors: Fujimura Hinata , Konuma Itsuki , Ugata Yosuke , Yabuuchi Naoaki
Published: December 2024

Toward the realization of sustainable society, the development of high-energy lithium-ion batteries is required. LiNiO2 is considered a promising positive electrode candidate owing to its high capacity. However, the gradual loss of electrode reversibility at high voltage region coupled with Ni migration to tetrahedral site on charging is observed on cycling.1 In this study, to improve electrode reversibility of LiNiO2, Li- deficient Li1–x
Ni1+x
O2 are synthesized and their electrochemical properties were examined. Stoichiometric LiNiO2 and Li-deficient Li1–x
Ni1+x
O2 were synthesized by mixing LiOH・H2O and Ni(OH)2 and calcined for 12 h at 650 oC under oxygen atmosphere. As shown Figure 1, Li deficiency significantly reduces particle size and crystallinity. In addition, the peak intensity ratio of 003 and 104 diffraction lines is decreased as Li content decreases, which indicates the increase of Ni ion occupation in Li layers. Compared with stoichiometric LiNiO2, Li deficient samples deliver a smaller discharge capacity, but higher electrode reversibility is achieved (Fig. 2). These facts suggest that Ni migration to adjacent tetrahedral sites is effectively suppressed by the presence of extra Ni ions in Li layers for the Li-deficient samples, leading to the high electrode reversibility.2 The impact of Li deficiency on electrochemical properties of LiNiO2 will be discussed in detail.

N. Ikeda et al., and N. Yabuuchi, J. Mater. Chem. A, 9, 15963 (2021).

I. Konuma et al., and N. Yabuuchi, Energy Stor. Mater. 66, 103200 (2024).

Figure 1
Factors Affecting Performance on Electrode Materials for Proton Batteries
Authors: Furuhata Shun , Ugata Yosuke , Yabuuchi Naoaki
Published: December 2024

Lithium-ion batteries (LIBs) are used in a wide range of applications such as electronic devices and electric vehicles. However, growing demand for LIBs raises concerns about the sustainable supply of Li resources. Therefore, battery systems composed of abundant elements are required to complement LIBs. A promising candidate is proton batteries, which have been extensively studied as energy storage applications. Nickel-metal hydride batteries (Ni-MH) are typical examples of proton batteries, but the low operating voltage restricts energy density. To solve this problem, fabrication of a bipolar-type cell, which uses sheet-type composite electrodes coated with positive and negative electrode materials on both sides of the current collector, is proposed as an effective approach to increase energy density and power density as battery modules. In this study, sheet-type composite electrodes of proton insertion materials are prepared by slurry coating method, and their electrochemical properties are examined. The prepared Ni(OH)2 and LaNi5 composite electrodes show reversible proton insertion/extraction behaviors in cyclic voltammetry and galvanostatic charge/discharge tests. In addition, a bipolar structured proton battery is successfully assembled with a cell voltage of >3 V. Impacts of polymer binders and conductive agents on the electrode performance and electrochemical characterizations of Ni-free proton insertion materials will be also discussed.
Anomaly Detection in Battery Charge-Discharge Experiments Using Multi-Task Auto-Encoder
Authors: Han Sangheon , Jung JinYoung , Han Skill , Kim Kyeongtaek
Published: December 2024

Battery charge-discharge experiments require a long time for data collection, often taking several months. It is impossible to stop the experiment immediately when anomalous data is generated, such as rapid capacity fade in batteries, leading to inefficient waste of time.

To effectively continue the experiment, it's important to monitor the battery charge and discharge process in real time to anomaly behavior early.

Recently, research has been actively conducted to predict the characteristics and lifetime of batteries using deep learning. However, this deep learning approach necessarily requires a large amount of reproducible learning data. The fact that battery data is highly affected by changes in experimental conditions such as C-rate and temperature.

In this paper, we propose an anomaly detection algorithm model applicable to various experimental conditions by using multiple Auto-encoders (AE). We define this model as Multi-task Auto-encoder (MTAE), where each AE model is trained on normal battery operation data collected under different C-rate conditions.

MTAE reconstructs raw data measured at each cycle during charge-discharge experiments based on the learned normal data and calculates the reconstruction error. Using the reconstruction error values, we establish the 'reconstruction error distribution' for normal battery operation data, and based on this, set a threshold for detecting anomaly data. If the reconstruction error exceeds the threshold, it's identified as anomaly data.

Real-time anomaly detection using raw data through MTAE showed higher performance compared to AE models trained solely on a single C-rate, as evaluated by the Area Under the Curve (AUC). Although this paper categorized data based only on C-rate, future research will extend to include various characteristics such as temperature and pressure.
Rechargeable Aqueous Sodium-Ion Batteries with Iron/Titanium-Based Oxides As Negative Electrode Materials
Authors: Hirakuni Nozomi , Ugata Yosuke , Yabuuchi Naoaki
Published: December 2024

Sodium-ion batteries with earth abundant elements have attracted much attention as an alternative to lithium-ion batteries in terms of their cost and abundant resources. In addition, aqueous sodium-ion batteries are expected to reduce the cost of battery manufacturing cost and solve safety issues. In this study, O3-type metastable Na0.5Fe0.5Ti0.5O2 oxide is synthesized, and their electrode performances as negative electrode materials for aqueous sodium-ion batteries are examined.

Metastable Na0.5Fe0.5Ti0.5O2 with cation vanact sites was synthesized by the chemical oxidation of NaFe0.5Ti0.5O2. Figure 1 shows the XRD patterns of Na
x
Fe0.5Ti0.5O2 before and after soaking into water. From diffraction lines, the crystal structure of both samples can be assigned as an O3-type layered structure. The weakend peak intensity of the 003 diffraction line and the shrinkage of c-axis value after soaking into water indicates the partial extraction of Na ions and the successful formation of Na0.5Fe0.5Ti0.5O2. This fact is further supported by oxidation of Fe after soaking into water by X-ray absorption spectroscopy (Fig. 2). Galvanostatic charge/discharge curves of the samples before and after soaking into water are shown in Fig. 3. The sample after soaking delivers a larger initial charge (reduction) capacity because of the Fe oxidation and enriched vacant sites in the host structure.

Based on these results, the electrochemical properties of Na0.5Fe0.5Ti0.5O2 and its potential application to aqueous sodium ion batteries will be discussed in detail.

Figure 1
Study on High-Voltage Cathode Li-Ni-Mn Spinel Oxides with Low-Temperature Magnetism
Authors: Ishimori Yuki , Sakurai Hiroya , Takada Kazunori , Nakamura Tatsuya
Published: December 2024

Lithium-ion rechargeable batteries have been attracting researcher’s interest, because they are candidate to address environmental issues, especially for application to electric vehicles and stationary energy storage systems. The battery operating voltage is one of the factor affecting the energy density of battery cell, and therefore positive electrode with high operating voltage is very attracting. A typical high-voltage cathode material, LiNi0.5Mn1.5O4 is an end member of LiNixMn2-xO4 solid solution compounds (0.00<x<0.50). From the previous study, it is known that LiNi0.5Mn1.5O4 spinel is a ferri-magnetic material with large magnetic moment and high transition temperature. In this work, the compounds of LiNixMn2-xO4 (0.40<x<0.50) are studied with both low-temperature magnetism and electrochemical charge-discharging. Additionally, the correlation between electrochemical and magnetic properties is also discussed.

LiNixMn2-xO4 (0.40<x<0.50) were prepared by gelation of nitrate/citrate solution, thermal decomposition at 500 ℃ and annealing under various conditions (temperature and atmosphere). Under the preparation condition at relatively low temperature (700 ℃) in oxygen atmosphere, they were single phase of cubic spinel with fine particles. The lattice parameters monotonously decreased, as x increased. The charge-discharge profiles have twin plateaus around 4.7 V, to Ni2+/Ni3+ and Ni3+/Ni4+ redox signals, with a small signal at ~4.0 V. The capacity at >4.5 V formers increased with x and that at <4.5 V was reduced. From the magnetic evaluation, the saturation magnetization at 2 K (Ms) increased with x, and simultaneously, the ferri-magnetic/paramagnetic transition temperature (Tc), evaluated from temperature dependence of the saturation magnetization, shifted higher. These results exhibited the following relation-ships (presented in Fig. 1); the capacity at >4.5 V was almost proportional to Ms, and the operating voltage was proportional to Tc. However, it was found that the magnetic response under weak magnetic field was not usual (shown in Fig. 2) and it implied two-step phase transition around Tc. The anomaly was thought to be attributed to magnetic in-homogeneity, which is very sensitive to the specimen characters. The analysis of experimental results of specimens prepared under different conditions are being carried out and then presented and discussed at the conference.

Figure 1
Multi-Dopant Influence on the Volume Changes of Layered-Oxide Cathodes for Lithium-Ion Batteries
Authors: Miyazaki Tatsuya , Minamida Atsusa , Kawai Kosuke , Kubota Kei , Okubo Masashi
Published: December 2024

The growing global market of electric vehicles demands performance improvement of lithium-ion batteries (LIBs). Layered transition-metal oxide (LiMO2) is widely used as cathode materials for LIBs owing to its large energy densities. However, LiMO2 exhibits a large volume change upon (de)lithiation, which induces a mechanical stress inside a particle.1 Consequently, interparticle cracking occurs with repeating charge/discharge cycles, resulting in severe performance degradation. Introducing redox-inactive cations within and between transition-metal layers has been widely employed to suppress such volume changes. For example, Zhang et al. proposed that doping Ti, Mg, Mo, and Nb into LiMO2 could improve the cycle performance by reducing the volume change upon charge/discharge.2,3 In this study, the roles of multiple dopants in suppressing volume changes of LiNi0.5Mn0.5O2 are investigated using operando X-ray diffraction measurements.

LiNi0.5Mn0.5O2 and four multi-doped samples (LiNi0.5Mn0.43Ti
x
Mg
y
Mo
z
Nb0.07–x–y–z
O2) were synthesized by the co-precipitation methods. Working electrodes were prepared by coating an Al current collector with a slurry of active material, acetylene black, and polyvinylidene fluoride at a weight ratio of 80:10:10. 2032-type coin cells were fabricated using the working electrode, Li metal as a counter electrode, and 1 mol L–1 LiPF6 ethylene carbonate/diethyl carbonate (1:1 v/v%) + 2 wt% vinylene carbonate as an electrolyte. Galvanostatic charge/discharge measurements were performed at a C-rate of 0.1C (28 mA g–1). Laminated cells with the LiMO2 electrodes and 1 mol L–1 LiPF6 ethylene carbonate/diethyl carbonate (1:1 v/v%) electrolyte were fabricated for operando X-ray diffraction measurements with a transmission mode.

Powder X-ray diffraction measurements confirm the successful synthesis of all LiMO2. Galvanostatic charge/discharge measurements show that LiNi0.5Mn0.5O2 (non doped), LiNi0.5Mn0.43Ti0.03Mg0.02Mo0.02Nb0.01O2 (4-element doped), LiNi0.5Mn0.43Ti0.03Mg0.02Mo0.02O2 (3-element doped (w/o Nb)) deliver larger reversible capacities (~190 mAh g–1) than LiNi0.5Mn0.43Mg0.02Mo0.02Nb0.01O2 (3-element doped (w/o Ti)) and LiNi0.5Mn0.43Ti0.01Mg0.02Nb0.04O2 (3-element doped (w/o Mo)). After the 70th cycle, non-doped LiNi0.5Mn0.5O2 exhibits greater capacity retention (90%) than four-element doped and three-element doped (w/o Nb) LiNi0.5Mn0.5O2 (86% and 85%, respectively). Operando X-ray diffraction measurements show that the volume change (ΔV/V) at 80% depth of charge was −4.2%, −1.8%, and –3.3% for no-doped, four-element doped, and three-element doped (w/o Nb) LiMO2. These results indicate that a Nb dopant plays an important role in the suppression of a volume change during the first charge.

Yan, P., et al., Nat Commun.
8, 14101 (2017).

Zhang, R., et al., Nature
610, 67–73 (2022).

Zhang, R. et al., Energy.
8, 695–702 (2023).

Figure 1
Theoretical Analysis of Anion Intercalation Process into Cathode Conductive Carbon
Authors: Nakamura Kou , Takenaka Norio , Hagiwara Satoshi , Otani Minoru , Yamada Atsuo
Published: December 2024

High-voltage Li-ion batteries have been extensively studied to increase the energy density of batteries. To achieve this goal, 5 V class cathode materials have been developed, but the long-term stable operation has not been achieved. Recently, we reported that the poor cycle stability comes not only from the oxidative degradation of the electrolyte and/or cathode active material, but also from side reactions caused by the insertion of anions into the interlayer of a cathode conductive carbon [1]. However, the detailed mechanism of anion insertion into the conductive carbon is still not well understood. In this study, we theoretically investigated the anion insertion process at the interface between a graphite and EC-based electrolyte solution (1 M LiPF6 / EC).

We adopted a density functional theory (DFT) in combination with the effective screening medium and reference interaction site model (ESM-RISM) method to analyze the insertion process of a PF6
- anion into the graphite [2]. The simulation cells are composed of graphite electrode (C252(PF6)9H36) and the 1 M LiPF6 / EC electrolyte, where the entire graphite electrode are treated quantum mechanically, whereas the electrolyte components are treated classically by the RISM method. The activation energy was calculated by computing the grand potential (Ω) at each point while moving a PF6
- anion from its initial position on the electrolyte side (r = 20 Å) to the electrode interior (r = 0 Å). These calculations were performed at two different electrode potentials, the potential of zero charge (PZC) and the equilibrium potential of the anion insertion reaction, respectively. All the DFT and ESM-RISM calculations were conducted using the Quantum Espresso v.6.1 code.

The figure shows the profiles of Ω along the insertion process of the PF6
– anion into the graphite layer. The activation energies were estimated to be 0.49 eV (ΩPZC, black line) and 0.37 eV (Ωeq, red line) at the PZC and the equilibrium potential, respectively, considerably smaller than that of Li+ (0.6 eV) [3]. Importantly, the coordination number of EC molecules around PF6
– (N
EC, blue line) decreases from about 10 Å and Ω becomes correspondingly unstable, indicating that the desolvation of PF6
– contributes significantly to the activation barrier. Furthermore, systematic calculations of the desolvation energies for different solvent species show that the calculated values tend to increase as the dipole moment of the solvent molecule decreases. Therefore, a use of solvents with smaller dipole moments would increase the desolvation energy, thus suppressing the anion insertion.

1) S. Ko et al., Joule, 5, 998 (2021).

2) S. Nishihara et al., Phys. Rev. B, 96, 115429 (2017).

3) J. Haruyama et al., J. Phys. Chem. C, 122, 9804 (2018).

Figure 1
Preparation and Characterization of LGVO/PEO Composite Electrolytes with Wet Process
Authors: Ozaki Taiyo , Nakamura Tatsuya , Kakibe Takeshi
Published: December 2024

All-solid-state lithium-ion batteries (ASSLBs) have become a good candidate for energy storage devices with safety and long-life time. It is essential to apply an appropriate solid electrolyte, because it is quite important to build the electrode/electrolyte interface with good chemical, electrochemical and mechanical properties [1, 2]. The previous studies reported that LISICON compound Li3.5Ge0.5V0.5O4 (LGVO) solid electrolyte has good compatibility with layered rock salt cathode oxides [3]. However, the LGVO solid electrolyte phase is easily reductive-decomposed in contact with lithium metal anode. In order to avoid direct contact between LGVO electrolyte and Li metal anode, it is useful to construct intermediate polymer electrolyte layer with high Li+ ionic conductivity between them. In this paper, the preparation conditions of polyethylene oxide based polymer electrolyte (PEO-based SPE) film by wet method were discussed. In addition, the polymer film was prepared on the LGVO solid electrolyte layer, and the LGVO/PEO interfacial properties were also studied.

PEO-based SPE slurry was prepared by dissolving PEO and different concentrations of Lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) with/without Al2O3 nanoparticle in acetonitrile. PEO-based SPE slurry was uniformly coated on the LGVO membrane and dried in a vacuum to obtain LGVO/PEO laminated electrolytes.

X-ray diffraction patterns of the several PEO-based SPE are shown in Fig. 1. Low Li+ concentrated PEO-based SPE (with Li+ : EO ratio = 1:20) exhibited typical PEO diffraction peaks at 15°, 19° and 23°. On the other hand, the crystallinity degree of PEO in high Li+ concentrated PEO-based SPE (with Li+ : EO ratio = 1:10) decreased dramatically. Especially, there are no diffraction peaks in high Li+ concentrated PEO-based SPE (with Li+ : EO ratio 1:10) with Al2O3 nanoparticle addition. Fig. 2 shows temperature dependence on the ionic conductivities of the PEO-based SPE (with Li+ : EO ratio 1:10) with Al2O3 nanoparticle in temperature range from 10 to 80 °C. The ionic conductivity of the PEO-based SPE showed a sufficiently higher ionic conductivity (4.25 × 10-3 Scm-1) at 60 °C.

This study was supported in part by the JST GteX (grant number JPMJGX23S2).

[1] E. Quartarone, P. Mustarelli, “Electrolytes for solid-state lithium rechargeable batteries: recent advances and perspectives”, Chem. Soc. Rev., 40, 2525-2540, (2011).

[2] R. Chen, Q. Li, X. Yu, L. Chen, H. Li, “Approaching Practically Accessible Solid-State Batteries: Stability Issues Related to Solid Electrolytes and Interfaces”, Chem. Rev., 120, 6820-6877 (2020).

[3] T. Okumura, T. Takeuchi, H. Kobayashi, “All-Solid-State Batteries with LiCoO2-type electrodes: realization of an impurity free interface by utilizing a co-sinterable Li3.5Ge0.5V0.5O4 electrolyte”, Appl. Energy Mater. 4, 30-34 (2021).

Figure 1
Study on the Structural and Electrochemical Characteristics of End of Life Battery Electrode Delaminating Process
Authors: Kim Byeoungseok , Jin Sungjin , Park Sangho
Published: December 2024

Demand for lithium-ion batteries (LIBs) has been increased dramatically over the years due to the rapid market expansion of electric vehicles and Energy storage system(ESS). Current commercial lithium ion batteries mainly contain nickel, cobalt, manganese metal oxides, lithium, phosphates, aluminum, copper, graphite, organic electrolytes and other chemicals. Therefore, the recycling and reuse of used lithium-ion batteries at the end of their useful life are of great interest by many researchers. However, due to the high energy density, high safety and low price of lithium-ion batteries, the difference and variety are large, which poses great difficulties in recycling waste lithium-ion batteries.

Lithium ion batteries recycling typically involves both physical and chemical processes. Physical processes typically include pretreatment and direct recovery of electrode materials. These processes typically include decomposition, crushing, screening, magnetic separation, washing, heat treatment, etc. The chemical processes can generally be divided into pyrometallurgical and hydrometallurgical processes which include leaching, separation, extraction and chemical/electrochemical precipitation. Recently, recycling technologies for lithium secondary batteries through a direct regeneration process have been attracting attention. Directly regeneration technique has the advantages of short recovery route, low energy consumption, eco-friendly compared to pyrometallurgical and hydrometallurgical processes. In order to recover the cathode active material from the separated electrode plate, a process for separating the PVDF binder and the cathode active material is required. In general, N-methyl-2-pyrrolidone (NMP) is the most common solvent for the manufacture of cathode electrodes in the battery industry. Although ~99% of the solvent used in electrode manufacturing is recovered, it is however limited in several countries due to negative environmental impacts.

In this study, the cathode materials were separated electrode from used lithium ion cell using various wet-chemistry. Chemical, structural, and electrochemical characteristics of the cathode materials and substrate were investigated.