bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Force-Responsive Hydrogel Made of Block Polyrotaxane
Authors: Maeda Rina , Masayuki Taniguchi , Uenuma Shuntaro , Mayumi Koichi , Yokoyama Hideaki , Ito Kohzo 
Published: February 2020

Stimuli-responsive polymers that are sensitive to certain triggers from the external environment have been attracting many researchers’ interests. Stimulus that can be used to trigger these materials have been varied from temperature, light, electrical or magnetic fields, to chemicals. However, some applications require new triggers such as force. We thought that polyrotaxane-based gel is a new candidate of force-responsive material. Polyrotaxane is a type of mechanically interlocked supramolecule consisting of polymer axle and ring molecules, in which multiple rings are threaded onto a polymer axle and prevented from dethreading by bulky end groups. When a force is applied to polyrotaxane gels, in which polyrotaxanes are crosslinked through ring molecules, ring molecules slide along an axle polymer to evenly distribute the applied force. Recently we created block polyrotaxane whose axle is a triblock copolymer poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-PPO-PEO).[1] β-Cyclodextrin (β-CD) form inclusion complex with PPO but not with PEO in water. We hypothesized that chemical property of the hydrogels obtained from this block polyrotaxane would be converted to hydrophobic by force. β-CDs should stay on PPO segment without loading, while β-CDs would slide from PPO to PEO segment to expose hydrophobic PPO segment when a force is applied. In order to confirm this concept, we studied hydrogels based on polyrotaxane made of β-CDs and PEO-PPO-PEO with several molecular weight and PEO/PPO ratio. Three polyrotaxanes compared in this study are followings; PEO60-PPO30-PEO60 with 17CDs (PPR_7k), PEO80-PPO70-PEO80 with 13CDs (PPR_11k), PEO110-PPO55-PEO110 with 12CDs (PPR_13k) (subscripts denote a number of repeating unit of each segment). 1H NMR measurements were conducted to investigate a position of β-CDs of a series of polyrotaxanes in water. It was found that β-CDs in the PPR_13k shuttles both on PEO and PPO segment but β-CDs in PR_7k and PR_11k stayed on PPO. Small-angle X-ray scattering (SAXS) was conducted to the hydrogels obtained from cross-linked polyrotaxane. Figure shows SAXS 1D profiles of the hydrogel obtained from PPR_11k. Before stretching, no peak was observed based on a periodic structure. Then this hydrogel was extended to 1.8 times of the original state to show a peak corresponding to a periodic distance of 29 nm. These results indicate PPO segments were exposed after loading to form hydrophobic periodic domains in PPR_11k. Other hydrogels obtained from PPR_7k and PPR_13k did not show any periodic structures even after loading. We are hoping that this new force-responsive block polyrotaxane system can be applied to the materials that can alter materials permeability by an applied force.
[1] S. Uenuma et al.
Chem. lett., 45 (8), 991-993 (2016)

Figure 1
A Photoresponsive Polymeric Actuator Topologically Cross-Linked by Movable Rings Based on a [2]Rotaxane Structure
Authors: Osaki Motofumi , Takashima Yoshinori , Yamaguchi Hiroyasu , Harada Akira 
Published: February 2020

A photoresponsive polymeric material, in which [2]rotaxane units with α-cyclodextrin (αCD) threading onto an azobenzene (Azo) derivative is used as a topological cross-link for the main chains of the polymeric material in aqueous media, was achieved.
As shown in Figure 1a, A polycondensation reaction between Lys-αCD/Am2Azo inclusion complex and Su2PEG gave polymeric material cross-linked by [2]rotaxane (αCD-Azo hydrogel). [2]Rotaxane structures in the αCD-Azo hydrogel were found to act as movable links in the polymer network, and the mechanical properties of the material were enhanced to show a rupture strain of 2800%. The materials were reversibly deformed by irradiation with UV or visible lights in aqueous media, which caused photoisomerization of the azobenzene moiety and changed the structure of the [2]rotaxane linker, leading to deformation of the polymer network (Figure 1b).
Surprisingly, the dry material (αCD-Azo xerogel), which had been uniaxially extended in air, showed a faster response than the αCD-Azo hydrogel. The orientation of the polymeric network in the materials enables the efficient response. As shown in Figure 1c, the αCD-Azo xerogel quickly bent towards the light source side within 3 seconds upon irradiation with UV light. 5.6 mg of the αCD-Azo xerogel also performed 5.6 μJ of mechanical work within 10 seconds by the UV-irradiation, which is approximately 50 times higher than that achieved in our previous work1.

Figure 1.
The preparation of the αCD-Azo hydrogel as a topological material (a), schematic illustration of the αCD-Azo hydrogel before and afeter the irradiation with UV (b), and lateral views of the αCD-Azo xerogel showing deformations driven by UV irradiation.
[1]. Iwaso, K.; Takashima, Y.; Harada, A. Nat. Chem.
2016, 8, 625-632.

Figure 1
Development of Ion Conductive Monolithic Polymers
Authors: Ahmed Kumkum , Naga Naofumi , Furukawa Hidemitsu 
Published: February 2020

Polymer monoliths composed with macroporous sizes are one of the potential candidates in separation technology and for efficient and stable separators in batteries and fuel cells [1]. Recently, thiol-ene "click" reaction has been received extensive attention in the field of monolith preparation owing to its exceptional versatility and propensity for the quantitative conversions under mild conditions along with extending the choice of versatile categories of functional monomers. In this work we report a wide variety of joint-linker type porous polymers induced by phase separation during polymerization, by utilizing thiol-ene reaction of multi-functional thiol, 1,3,4-Tris(3-mercaptobutyloxethyl)-1,3,5-triazine-2,4,6- (1H,3H,5H)-trione (3T), pentaerythritol tetrakis(3-mercaptobutylate) (PTMB) etc. as the joint molecules, and poly (ethylene glycol) diacrylate-1000 (PEGDA-1000) as the linker molecules in ethanol. Ion conducting phenomenon of these monoliths has been introduced by swelling them in a wide variety of Ionic liquids (IL). We have studied the concentration effect of joint molecules and temperature on the physical features of these monolith polymers. These microporous monoliths exhibited diverse mechanical prosperities and morphology. In contrary to ionic gels [3] the monolithic structure with entrapped ILs exhibited high ionic conductivity due to the loosely bound ions within the porous polymer network. Physical properties of these IL entrapped monoliths have been investigated to optimize suitable IL-monolith combination for best performance in application of separator membranes for batteries and for separation technology.
References

Sakakibara, K., Kagata, H., Ishizuka, N., Sato, T., Tsujii, Y. Fabrication of surface skinless membranes of epoxy resin-based mesoporous monoliths toward advanced separators for lithium ion batteries. J. Mater. Chem. A, 5, 6866–6873 (2017).

Liu, Z., Ou, J., Zou, H., Click polymerization for preparation of monolithic columns for liquid chromatography. Trends Anal. Chem., 82, 89–99 (2016).

Ahmed, K., Naga, N., Kawakami, M. & Furukawa, H. Development of ionic gels using thiol-based monomers in ionic liquid. 9800, 980005 (2016).
(Invited) Bioinspired Materials that can Sense and Adapt to Mechanical Loadings and Damages
Authors: Orrego Santiago , Krekora Urszula , Kang Eugene , Hou Decheng , Kang Sung Hoon 
Published: February 2020

Nature provides numerous examples of advanced materials with remarkable properties. Inspired by natural systems, there have been active efforts to understand design principles of natural materials and to synthesize bioinspired materials with outstanding properties. We have been inspired by natural structural materials with outstanding mechanical properties such as bone, coral reef, and wood that can adapt to their surrounding environment. For instance, bone can control mineral quantity proportional to the amount of stress from its sensing and mineral synthesis control mechanism. It becomes stronger in locations subjected to the higher mechanical loads, and vice versa. This leads to the formation of mechanically efficient structures for optimal biomechanical and energy-efficient performance.
However, it has been a challenge for making synthetic materials that sense change of loading conditions and damage and change their structures and properties to adapt to new conditions. Moreover, materials degrade over time due to fatigue and damages accelerate the degradation rate, resulting in reduction in the lifetime of the materials and increase of the maintenance costs. If materials can repair damages, we can have more efficient use of materials with reduced associated costs. Synthesizing materials that can sense and adapt to mechanical loading and repair damages, can help us to use materials for a broad range of loading conditions with extended lifetime and reduced costs.
To address the challenge, we are inspired by previous findings that bones are formed by mineralization of organic scaffolds using ions from blood. We report a material system that triggers mineral synthesis from simulated body fluids onto organic scaffolds upon mechanical loadings and/or damages so that the material can modulate its mechanical properties to adapt to loadings and regenerate upon damages. For example, we observed ~40% increase in the modulus of the material upon periodic loadings for 3 days. We also observed that the material could self-repair damages generated by removing ~5 μm thick minerals from the matrix, in 7 days. In addition, we demonstrate a simple way of making functionally graded material based on stress distribution within a material that results in graded deposition of minerals. We envision that our findings can open new strategies for making synthetic materials with self-adaptable mechanical properties and self-repair capability as well as tuning material properties on-demand.
Effect of H2 Evolution in Aqueous Aluminum Air Battery
Authors: Zhou Chong , Bhonge Kaustubh , Cho Kyu Taek 
Published: February 2020

The demand of electrical energy system is increasing rapidly these days for diverse applications from portable electronics and electrical vehicles to grid-scale energy storage. Lithium-ion battery has been utilized for most of those applications, but due to high cost (about $600/ kWh) and lower energy density (0.38 kWh/kg) [1], the advent of low cost and high performing battery system is required. Metal-air system, which has metal as a reactant for the anode side and oxygen for the cathode side of the battery cell, is getting intense attention due to its benefits such as high energy density and low system cost. Especially, metals such as lithium, aluminum, magnesium, calcium, iron, and zinc whose reduction potential is substantially low are typically used for the negative electrode, while oxygen generally from air is used for the positive side.
The energy density of the metal-air battery systems is 3 to 10 times greater than that of the conventional lithium ion battery (i.e. specific energy of the metal-air system is in the range from 0.8 to 3.9 kWh/kg, while that of the conventional lithium ion battery is 0.38 kWh/kg) [2].
Especially, aluminum of which specific energy is roughly 10 times greater than lithium ion battery is abundant, low price, environmentally benign, and inertness to humid operating condition, preventing the catastrophic thermal failure which is the major safety issue of the conventional system. However those promising systems could not be fully utilized due to the challenging issue associated with the redox reaction of metal electrode: self-corrosion reaction (i.e. hydrogen evolution)[3].
In this study, the effect of H2 evolution due to aluminum corrosion on the cell performance will be investigated through combined research of experiment (cell-based and component-based tests) and physics-based computational model. Especially, the coverage of H2 bubbles on the electrode surface, change of diffusion layer thickness affected by the H2 bubble rise, and change in the electrolyte conductivity will be analyzed with respect to various pH conditions, flow rate conditions, and currents. The results will be utilized to understand the underlying physics of H2 bubble issues and to define the key controlling parameters for the cell performance.

Reference

[1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J.-M. Tarascon, Nat Mater 2012, 11, 19-29.
[2] Q. Li, N. J. Bjerrum, J. Power Sources 2002, 110, 1-10.
[3] D. R. Egan, C. Ponce de León, R. Stokes, F. C. Walsh, J. Power Sources 2013, 236, 293-310.
Efficient Third-Party Abstraction of Lithium-Ion Batteries for Asset Modeling
Authors: Rogall Martin , Greenwood David , Barai Anup , Bhagat Rohit , Luk Patrick , Brucoli Maria 
Published: February 2020

As part of international strategies towards high penetration of renewable energy sources, the implementation of energy storage systems in power grids becomes increasingly necessary for short- and long-term energy deferral. Due to technical advantages in short-term and overall practical advantages, Lithium-Ion batteries are excellent storage mediums and already serve today widespread in a variety of applications both stationary and mobile.
However, most storage systems are privately funded. To investors, battery storage is considered an asset with high capital expenditure and slow, only partially predictable return on investment. The value estimation of storage systems is intercepted by two major difficulties. The first issue is the inherent complexity of batteries regarding performance and aging, which requires in-depth knowledge for accurate statements. The second issue is the inability to determine the optimal operation strategy due to the sizable portfolio of potential applications, reaching from frequency response over arbitrage to peak-shaving, and the potential impact of each on the storage system.
Investors are commonly provided with very few details on the battery itself and don’t always have the background knowledge necessary to accurately predict battery behavior and value generation in long term due to this complexity. This makes battery storage less tangible and less attractive than other assets.
This presentation introduces a tool for potential customers of battery storage that can be applied to any market-available carbon-based Li-Ion battery technology. It aims to provide an approximation for the battery’s lifetime behavior based on a multi-physics model. Electrical, thermal and aging models are constructed from literature and scaled and enhanced through experimental data.
The tool, which is developed in Python, takes as input the maximum amount of information available to customers in advance while making the minimum amount of assumptions about the storage system. The tool produces an approximation for the degradation of the storage system on an absolute and linear scale and can therefore be used inside optimization algorithms or as pre-processing tool. It is designed to be easily transferable and computationally efficient enough to allow for flexible parameter adjustment and multi-case comparison between storage providers and applications on any scale.

Figure 1
Performance and Stability of Cathode Electrode Under Carbon Capture Operating Conditions
Authors: Hilmi Abdelkader , Geary Timothy C , Franco Adam , Yuh Chao-Yi 
Published: February 2020

Introduction
The high-temperature molten carbonate fuel cell (MCFC) is one of the most advanced clean power generating devices. To date >8 billion kWh of clean electricity has been produced commercially using this new technology. The high operating temperature of MCFC (550-650°C) dramatically improves the reaction kinetics and eliminates the need for a noble metal catalyst. The electrochemical reactions taking place during cell operation involve CO2 transfer from cathode to anode through electrolyte matrix in the form of carbonate ions (Figure 1). The transport of CO3
= is equivalent to that of O= and CO2 (CO3
= ⇔ O= + CO2). Therefore, MCFC stack technology can be utilized for efficient simultaneous power generation and CO2 separation/capture by integrating with conventional combustion-based coal and/or natural-gas power plants.
The state of the art MCFC cathode is porous lithiated NiO. The cathode performance and stability are affected by several factors such as gas composition, temperature, electrode structure, and electrolyte chemistry. To ensure long-term performance and material stability (such as NiO cathode dissolution, polarization loss and CO2 capture efficiency), material selection, operating characteristics, and electrode design need to be carefully considered.
FCE has operated numerous bench-scale single cells (100 W) and technology stacks (30 kW) under carbon capture operating conditions (4-5% CO2 in the cathode inlet as opposed to >15% in baseline MCFC systems) to understand parameters affecting performance, life, and to investigate design solutions for further enhancement. Figure 2 shows similar NiO cathode stability under standard as well as carbon capture conditions, projecting to useful life of >7-years under both operation conditions. More endurance carbon capture tests are being conducted for further verification.
This paper will review the cathode material stability, microstructure, and durability under long-term carbon-capture operations. The effect of parameters such as electrolyte fill, gas composition and electrolyte chemistry, as well as approaches to enhance the CO2 capture efficiency and life, will be discussed.

Figure 1
Real-Time Imaging Analysis on Dendrite Formation of Aluminium Metal Anodes
Authors: Liu Hao-Wen , Wu Nae-Lih , Huang Hsiao-Wen , Chiang Chien-Chih , Yang Chang-Chung 
Published: February 2020

In recent years, rechargeable batteries are one of the most attractive options for both grid electrical energy storage and electrical vehicle (EV) applications due to the steadily increasing demands. Aluminum is the most abundant metal in the earth’s crust. Rechargeable aluminum-ion batteries (AIBs) is a promising research for future energy storage technologies due to its impressive advantages such as high anode capacity (gravimetric capacity of 2980 mAh g−1, and volumetric capacity of 8040 mAh cm−3), cost effectiveness, and safety. A recent study reported by Dai et al. cooperate with ITRI opened a new stage for this topic by employing an AlCl3/[EMIm]Cl ionic liquid electrolyte and graphitic cathode. This pioneering work has been stimulating various research enthusiasms in aluminum-ion batteries (AIBs).
At present, there are multiple challenges that need to be overcome in AIBs, including, for example, decomposition of the electrolyte material, small charge-discharge voltage window of the battery, and small energy/power densities, (compared with commercially available lithium batteries). The occurrence of aluminum dendrites, which could cause safety hazards, on the other hand, has not drawn sufficient attention.
In this study, we studied in real-time using optical microscopy the occurrence of dendritic aluminum electrochemical plating and its dendrite formation mechanisms. In particular, extensive real-time optical microscopy imaging and post mortem SEM analyses are carried out in conjunction with electrochemical characterizations to reveal the underlying mechanisms for the resulting effects.

Figure 1
Modeling the Electrical and Thermal Behaviors of a Lithium-Ion Battery Under External Short Circuit Conditions
Authors: Cho Jaesung , Koo Boram , Shin Chee Burm , Ha Yoon-Cheol 
Published: February 2020

The lithium-ion battery (LIB) is the primary choice for many applications such as mobile electronics, electric vehicles, and stationary energy storage solutions due to its high energy density, high voltage and low self-discharge rate. Reported safety incidents related to LIBs have resulted in an increased attention toward the safety issue of the LIB. In the operation of LIBs, there are many sorts of field failures including overheat, overcharge, and short circuit. External short circuit (ESC) is a severe fault which causes the large current flow and high temperature rise in an LIB immediately. Modeling to predict the maximum current flow and temperature rise of an LIB under ESC fault is essential to design an effective fault detection and diagnosis system for the safety management of LIB.
In this work, a modeling is performed to predict the electrical and thermal behaviors of an LIB cell under ESC conditions. The validation of the modeling approach is provided through the comparison of the modeling results for a 75Ah LIB cell from KOKAM with the experimental measurement data obtained from the ESC tests. The ESC tests were carried out using the external resistances of 0, 2, and 5 mΩ. Model predictions reasonably reproduce the experimental data.
Application of the Maximum Power Point Tracking (MPPT) Algorithm on Lithium-Ion Batteries
Authors: Shrestha Sujan , Dion Matt , Sholin Mark 
Published: February 2020

This work focuses on the application of the maximum power point tracking (MPPT) algorithm to discharge lithium-ion batteries at their maximum possible power. This algorithm is routinely applied in photovoltaic applications but has only seen limited application in battery applications so far.
A simple form of the MPPT algorithm is used in this work. A fixed magnitude of current is applied, and the new value of power is calculated. If the new value of power is greater than the previous one, the current is varied in the same direction until the maximum power is reached. This algorithm is simple to implement and consumes low computing power. However, the magnitude of a current step should be optimized. If the current step is very small, the time taken to reach the maximum power will be too long. And if the current step is very large, there will be a large oscillation near the power maxima.
Therefore, we study the effect of current steps during application of the MPPT algorithm on lithium-ion batteries. Comparative studies between various optimization methods such as gradient descent, steepest descent and Newton’s method are made. The effect of discharging batteries at their maximum power on their life cycle is also investigated.
The information obtained from this study can be a useful guide to designing a battery management system that gets the maximum performance out of a lithium-ion battery.

References

Selvan, P. Nair and Umayal, “A review of photovoltaic MPPT algorithms,” International Journal of Electrical and Computer Engineering, 6, 2016, 567-582.

A. B. Vieira and A. M. Mota, “Maximum power point tracker applied in batteries charging with PV panels,” 2008 IEEE International Symposium on Industrial Electronics, Cambridge, 2008, 202-207.

Kim, S. Mohan, J. B. Siegal and A. G. Stefanopoulou, “Maximum power estimation of lithium-ion batteries accounting for thermal and electrical constraints,” Proceedings of the ASME 2013 Dynamic Systems and Control Conference, California, 2013.