bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Stable and Active Ru Clusters Supported on Boron Carbon Nitride for Acidic Water Oxidation
Authors: Bai Xiaofang , Zhang Xiuping , Sun Yujiao , Huang Mingcheng , Fan Jiantao , Xu Shaoyi , Li Hui
Published: February 2024

In recent years, metal oxides, such as IrO2, have been widely used in proton exchange membrane water electrolysis (PEMWE) because of their excellent catalytic activity and long-term stability [1]. However the high price and scarcity of these catalysts were not enough to meet the requirements of PEMWE [2]. Therefore, it is significant to explore novel electrochemically active, stable, and low-cost catalysts.

In this paper, a uniformly dispersed Ru confined on boron carbon nitride support was synthesized and studied. The surface chemical states of Ru were tuned by the interaction between Ru and the active N in boron carbon nitrogen (BCN), forming a highly stable Ru-N bond. Benefiting from a graphene-like structure, the BCN-0.5Ru catalyst exhibited greater conductivity than RuO2. The strong interaction between Ru and the BCN support also allowed for accelerated charge transfer at the electrode interface.

Transmission electron microscopy (TEM) investigations revealed that Ru clusters were uniformly dispersed on BCN (Figure 1a), and the particle size distributions (Figure 1b) showed that the Ru clusters possessed an average particle size of 4 nm. It suggests that the Ru nanoclusters on the BCN support had small particle sizes and a narrow particle size distribution. These results demonstrated that the BCN support helped disperse the Ru metal nanoclusters more homogeneously than what occurred when RuO2 was prepared via direct RuCl3 annealing. The electrochemical performance of oxygen evolution reaction (OER) for BCN-xRu catalysts in O2-saturated 0.5 M H2SO4 solution was evaluated. The BCN-0.5Ru catalyst demonstrates a low overpotential of 164 mV at a current density of 10 mA cm–2 and remains stable for 12 h in acidic electrolyte (Figure 1c). In contrast, RuO2 without any support fails in only 1 h (Figure 1c). We propose that the surface chemical states of Ru supported by BCN may play an important role in enhancing stability. This study provides insights into designing and synthesizing high-performance electrocatalysts for acidic OER.

References

[1] An L, Wei C, Lu M, et al. Recent Development of Oxygen Evolution Electrocatalysts in Acidic Environment[J]. Advanced Materials, 2021, 33: 2006328.

[2] Gao J, Tao H, Liu B. Progress of Nonprecious-Metal-Based Electrocatalysts for Oxygen Evolution in Acidic Media[J]. Advanced Materials, 2021, 33: 2003786.

Figure 1 (a) TEM, (b) Particle size distributions, and (c) Chronopotentiometry tests at 10 mA cm–2 of BCN-0.5Ru

Figure 1
Anodic Dissolution of Aluminum in Sodium-Ion Batteries: A Comparison of Electrolyte and Solvent Composition
Authors: Colbin Lars Olow Simon , Hall Charles Aram , Etman Ahmed S. , Buckel Alexander , Nyholm Leif , Younesi Reza
Published: February 2024

The anodic dissolution behavior of aluminum was studied in various sodium-based electrolyte solutions using cyclic voltammetry and chronoamperometry. The aim was to investigate how different electrolyte and solvent compositions affect the dissolution process. The electrolyte solutions tested included 0.284 m NaBOB in TEP, 1.00 m NaPF6 in TEP, 1.00 m NaPF6 in EC:DEC, 1.00 m NaPF6 in diglyme, 1.00 m NaFSI in PC, and 1.00 m NaFSI in TEP. SEM imaging was also performed to analyze the morphological changes of the aluminum surface during the dissolution process.

To emphasize any dissolution process, relatively large volumes (3-5 ml) of electrolyte solution was used in polytetrafluoroethylene beaker cells. A three-electrode configuration was used to obtain the desired accuracy in the electrochemical tests.

Severe anodic aluminum dissolution was not observed below 5.3 V vs. Na+/Na in electrolyte solutions containing NaBOB in TEP, NaPF6 in TEP, NaPF6 in EC:DEC, or NaPF6 in diglyme. Anodic dissolution was, however, detected in electrolyte solutions containing NaFSI in PC and NaFSI in TEP, affirming that caution should be exercised when using FSI-anions with aluminum current collectors.1,2 Yet, the choice of solvent used with NaFSI appeared to influenced the anodic dissolution behavior of aluminum. Here, TEP seemed to suppress the initial dissolution, compared to PC.

In summary, this study provides insights into the anodic dissolution behavior of aluminum in sodium-ion batteries, and highlights the significance of selecting appropriate solution compositions to mitigate potential anodic dissolution issues. The findings contribute to the understanding of the electrochemical behavior of aluminum in the context of sodium-ion batteries, and provides a foundation for further studies.

The authors acknowledge The Swedish Energy Agency via project no. 50177-1, VINNOVA via projects no. 2022-01465 and 2019-00064 (Batteries Sweden), and H2020 research and innovation programme under Grant agreements No 958174 and 963542 for financial support.

1. L. Otaegui, E. Goikolea, F. Aguesse, M. Armand, T. Rojo and G. Singh, J. Power Sources, 2015, 297, 168–173.

2. A. Bitner-Michalska, A. Krztoń-Maziopa, G. Żukowska, T. Trzeciak, W. Wieczorek and M. Marcinek, Electrochim. Acta, 2016, 222, 108–115.

Figure 1
Internally Connected Porous Polymer Electrolyte Membrane for Long-Lasting Flexible Zinc-Air Batteries
Authors: Kim Kwang Won , Yoon Ki Ro , Choi Seon-Jin
Published: February 2024

The market of various wearable devices is rapidly growing in the recent. Accordingly, a light, safe, and flexible power source is also required to operate. The lithium-ion batteries (LIBs) are optimized for portable devices and can be miniaturized, but they are vulnerable due to the use of organic electrolytes and have limited theoretical energy density. The zinc-air battery (ZAB), as a next-generation battery, have garnered attention for its specific energy density (~1350 Wh/kg) and price competitiveness compared to the LIB. In particular, the use of an aqueous-based polymer electrolyte can provide safety and flexibility, making it a promising energy source for wearable devices. However, the open cathode structure of ZABs for breathing air as an active material leads to gradual loss of liquid components in the polymer electrolyte, resulting in decreased performance.

Herein, we developed a porous hybrid polymer membrane to overcome the aforementioned issues by means of the introduction of superabsorbent polymer (SAP) and the formation of internal network design of the membrane. First, a polyacrylic acid (PAA), one of the SAP, based fibrous network was constructed through an electrospinning process. Second, polyvinyl alcohol (PVA) as an ion conductive polymer was cast on the PAA framework, and subsequently impregnated with KOH electrolyte to form a gel-polymer electrolyte (GPE). Interestingly, the sacrificial PAA framework forms internal pores along with the fiber network, which can act as water pockets affording fast ionic conduction through the membranes and providing a higher electrolyte retention effect. As a result, the hybrid GPE had approximately three times higher ionic conductivity compared to pure PVA and better retention, resulting in outstanding electrochemical performance and cycle-life of the ZAB cell. We believe that our unique design approach for GPE can accelerate the commercialization of flexible ZABs and extend the market of wearable devices.

Figure 1
A Near Dimensionally Invariable Electrode Material: Li8/7Ti2/7V4/7O2
Authors: Konuma Itsuki , Yabuuchi Naoaki
Published: February 2024

Our group has reported that Li-excess V-based oxide with Nb ions, Li1.25Nb0.25V0.25O2, delivers a large reversible capacity of over 250 mA g-1 with V3+/V5+ two-electron redox reaction.[1] Recently, Li8/7Ti2/7V4/7O2 has been also synthesized and examined as high-capacity positive electrode materials with V cationic redox.[2] Nanosized Li8/7Ti2/7V4/7O2 was also synthesized by high-energy mechanical milling. Nanosized Li8/7Ti2/7V4/7O2 delivers a high reversible capacity of ~300 mA h g-1 with no capacity deterioration for 100 cycles, which originates from a near dimensionally invariable nature as high-capacity electrode materials. Moreover, Li8/7Ti2/7V4/7O2 is used for as positive electrode materials for all-solid-state batteries with argyrodite-type electrolyte, Li6PS5Cl. An all-solid-state cell with Li8/7Ti2/7V4/7O2 and Li6PS5Cl delivers a large reversible capacity of 300 mA h g-1 with excellent retention for 700 cycles. From these results, the importance of a near dimensionally invariable character is discussed in detail.

[1] M. Nakajima and N. Yabuuchi, Chem. Mater.,
29, 6927 (2017)

[2] I. Konuma et al. and N. Yabuuchi, Nat. Mater., 22, 225 (2023)
An Insight into the Lithium Plating – Operando Gas Evolution Study
Authors: Sandra Amritha , Mattinen Ulriika , Lindstrom Rakel
Published: February 2024

Lithium-ion batteries (LiBs) play a major role in the electrification of transportation systems as a step forward in achieving a sustainable carbon neutral society [1]. Fast-charging is regarded as one of the most necessary features for lithium-ion batteries in order to speed the widespread adoption of electric vehicles [2]. However, we have previously shown that charging LiBs at high C-rate cause the evolution of high amount of ethylene gas along with capacity fade [3]. It is well known that fast charging is also may result in lithium plating and allied parasitic reactions [4]. Since many of the side reactions in LiBs are associated with evolution of products in gaseous phase, operando mass spectrometric techniques can be used to better understand these unwanted reactions. We have developed an Online Electrochemical Mass Spectrometry (OEMS) set-up to study the gases formed on a Li-plated electrode, to provide the fundamental understanding of the reaction mechanism at the electrode/electrolyte interface.

References

[1]. Bibra, E. M. et al. Global EV Outlook 2021: Accelerating Ambitions Despite the Pandemic. (2021).

[2]. Huang, W., Ye, Y., Chen, H. et al. Onboard early detection and mitigation of lithium plating in fast-charging batteries. Nat Commun
13, 7091 (2022).

[3]. Mattinen, Ulriika, et al. "Gas evolution in commercial Li-ion battery cells measured by on-line mass spectrometry–Effects of C-rate and cell voltage." Journal of Power Sources 477 (2020): 228968.

[4]. Mussa, Abdilbari Shifa, et al. "Fast-charging to a partial state of charge in lithium-ion batteries: A comparative ageing study." Journal of Energy Storage 13 (2017): 325-333.
Efficient Sodium-Ion Storage Using MoS2@rGO Nanocomposite Anode: Exploring Na-Ion Diffusion in Metallic Phase
Authors: Singh Manish Kumar , Pati Jayashree , Prasad Jagdees , Chang Jeng-Kuei , Dhaka Rajendra
Published: February 2024

Sodium-ion batteries (SIBs) are gaining attention as a better and more economical option than lithium-ion batteries, owing to the abundance and low cost of sodium in comparison to lithium. The anode component of rechargeable batteries plays a vital role in obtaining superior energy and power density. Consequently, the investigation of novel materials for SIBs with enhanced performance is imperative. Transition metal chalcogenides (TMDs) are found to be promising contenders for this purpose, particularly MoS2 due to their two-dimensional open framework, structural tunability, and high theoretical specific capacity as an anode material in sodium ion storage. In this regard, we conducted a facile strategy to synthesize MoS2 and aluminium-doped MoS2 incorporated into reduced graphene oxide (rGO) using the hydrothermal method. The structural and morphological properties of the samples have been explored through X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) measurements which revealed that the addition of aluminium increased the interlayer spacing of the (002) plane of MoS2 nanosheets and stabilized it in metallic 1T phase. The enhanced interlayer distance and improved conductivity of the electrode material displayed a significantly higher initial discharge specific capacity of around 750 mAhg−1 which is stabilized around 380 mAhg−1 at the current rate of 50 mAg−1 after 10 cycles as investigated through galvanostatic charge-discharge measurement. The long cycling test for 200 cycles revealed the capacity retention of ~65% and ~55 % at the current density of 100 and 300 mAg-1, respectively. The kinetic behavior of the Na-ion is studied employing cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS), and the diffusion coefficient of Na-ion in the bulk of the electrode was found to be in the range of 10-10 to 10-12 cm2s-1. Additionally, in-situ EIS analysis demonstrates the electrode's electrochemical kinetics at different charge-discharge states by showing variations in charge transfer resistance. Ex-situ XRD and X-ray photoemission spectroscopy (XPS) demonstrated the coexistence of 1T and 2H phases, and field-emission SEM validated the stable morphology after cycling.

Keywords: Sodium-ion batteries, Transition metal chalcogenides (TMDs), Anode material, MoS2

References:

N.Tapia-Ruiz et al., 2021 Roadmap for sodium-ion batteries, J. Phys. Energy 3, 031503 (2021).

M. Kr. Singh, J. Pati, D. Seth, J. Prasad, M. Agarwal, M. A. Haider, J.-K. Chang, and R. S. Dhaka, Diffusion mechanism and electrochemical investigation of 1T phase Al–MoS2@rGO nano-composite as a high-performance anode for sodium-ion batteries, Chemical Engineering Journal 454, 140140 (2023).
Metal-Organic Frameworks Based Autonomous Water Harvesting & Sustainable Energy Generation from Ambient Air
Authors: Lee Ji Hyun , Choi Seon-Jin , Yoon Ki Ro
Published: February 2024

Recently, hydro-electric nanotechnology is touted as promising next-generation renewable energy because it can employ environmentally friendly sources for producing electricity. However, conventional hydro-electric nanotechnology is hampered by limitations, such as artificial induction of water stream and a low production level of energy. In this work, we developed an autonomous water harvesting & sustainable electrical energy generation system that overcomes the limitations of conventional renewable energy. Autonomous water harvesting & sustainable electrical energy generation system was successfully achieved with two distinctive metal-organic frameworks (MOFs), that are, an amine-functionalized Zr-based MOF (UiO-66-NH2) particles for atmospheric water harvesting, and a highly conductive Ni3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) MOF-grown cotton-fabric for producing electrical energy. The environmentally responsive UiO-66-NH2 harvests water from airborne air and the condensed water spontaneously produces electrical potential between wet- and dry-Ni3(HITP)2, resulting in electrical energy generation with a maximum power and energy densities of 2.6 μW cm-3 and 1.1 mJ cm-3, respectively. Our integrated water harvesting and energy generation systems can pave the way for realizing a hydro-electric nanogenerator as a next-generation energy harvesting system.

Figure 1
Survey of Activated Cleaning Chemistries for Low-Stress Post-Chemical Mechanical Planarization Cleaning of Silicon Carbide
Authors: Powell Joseph L. , Keleher Jason J.
Published: February 2024

Integrated Circuit (IC) technologies have begun transitioning to wide band gap (WBG) substrates (i.e., Silicon carbide (SiC)) due to the intrinsic properties (i.e., high capacitance, thermal stability, and wear resistance) of these semiconducting materials. This has led to the development of Chemical Mechanical Planarization (CMP) processes that use aggressive chemical conditions and increasing mechanical forces to reach optimal material removal rates (MRR). The harsh CMP process parameters often result in contamination/defectivity (i.e., organic residue, abrasive particles, etc.) left on post-polish substrate surfaces and thus posing difficulty within the post-CMP cleaning process. Traditionally, post-CMP cleaning utilizes a polyvinyl alcohol (PVA) brush scrubbing method on the substrate surface. This has been shown to cause secondary defects (i.e., scratches, particle agglomerations, etc.) that inevitably lead to overall device failure. Alternative post-CMP methods utilize non-contact cleaning via megasonic energy to target removing defects (i.e., organic residue, pad debris, particle agglomerations, etc.) and avoid secondary defect generation. This research surveys post-CMP cleaning processes (contact and non-contact) on SiC substrates with various cleaning chemistries (i.e., supramolecular surfactants, catalytic complexes for generating reactive oxygen species (ROS), non-metal catalyst). Initial results show that supramolecular surfactants can produce high particle removal efficiency (PRE) due to their ability to be broken down into their monomeric units and encapsulate any removed residue under both brush and megasonic conditions Additionally, increased ROS generation disrupts the non-covalently adsorbed defects to the SiC surface and leads to an increased cleaning efficiency while decreasing the overall variability of particle removal results. Combining the ROS systems' disruptive power with surfactants' encapsulation mode, a highly efficient clean with low variability can be achieved under low-stress conditions.
(Invited) Operando Approaches for Observing Reactions at Buried Electrochemical Interfaces
Authors: Weatherup Robert S.
Published: February 2024

The performance of materials for electrochemical energy storage and conversion depends critically on reactions taking place at the interfaces between these materials and their operating environment: from the reversible incorporation of ions at electrode−electrolyte interfaces in rechargeable batteries, to the conversion of the waste carbon dioxide into liquid fuels. As the reaction conditions change so these interfaces change, with often dramatic effects on their structure and chemical state. Understanding the evolution of these interfaces under realistic conditions is critical to the selection and design of improved electrochemical materials. However, it is extremely challenging to extract this information during operation, due to interference from the bulk phases either side of these buried interfaces, which disturb most interface-sensitive probes.1,2

I will give an overview of our recent efforts to develop operando approaches for resolving the structural and chemical evolution of electrochemical interfaces.3-8 This includes enclosed reaction cells sealed with X-ray/electron-transparent membranes such as thin (<100 nm) silicon nitride or graphene membranes that remain impermeable liquids. We thereby use soft X-ray absorption spectroscopy (sXAS) to observe solid-electrolyte interphase (SEI) formation on Li-ion battery anodes,4 and changes in the chemical state of transition metal electrocatalysts under electrochemical control. I will further discuss our recent progress in depositing thin lithium layers onto solid electrolytes,5,6 and using hard X-ray Photoelectron Spectroscopy (XPS) to study electrode-electrolyte interfaces in all-solid-state batteries.7,8 The development of these interface-sensitive operando approaches is expected to provide valuable tools for revealing a wide range of interfacial reactions. Collaboration across European and international partners has been critical to this work, and I will highlight how European funding has helped make this possible and the benefits associated with this.

References

Wu et al. Phys. Chem. Chem. Phys.
2015, 17, 30229.

Weatherup et al. Top. Catal.
2018, 61, 2085.

Velasco-Velez et al. Angew. Chemie
2015, 54, 14554.

Swallow et al. Nature Commun.
2022, 13, 6070

Weatherup et al. J. Phys. Chem. B
2018, 122, 737.

Khatun et al. Electrochimica Acta 2022, 431, 141145

Narayanan et al. Nature Commun.
2022, 13, 7237

Gibson et al. Faraday Discuss.,
2022
, 236, 267
(Invited) Multifunctional Plasma-Enabled Low Dimensional Nanoarchitectures: From Synthesis to Devices
Authors: Borras Ana
Published: February 2024

In this presentation, we will give an overview on our last advances in the exploitation of plasma and vacuum deposition methods for the nanoengineering of thin films and supported low-dimensional materials. A key step in the development of such nanoarchitectures is the implementation of a soft-template procedure based on the use of single-crystal small-molecule nanowires grown on processable substrates under mild conditions. We will demonstrate the application of vacuum and plasma-assisted deposition techniques to develop complex nanowires (NWs) and nanotubes (NTs) with a core@multishell morphology where each shell adds functionality or multifunctionality to the system. The steps required for the integration of these nanomaterials as supported or in-device applications will be presented. Two final applications will drive the presentation, namely, the development of multisource energy harvesters (and self-powered sensors) and novel approaches for smart and efficient de-icing by acoustic waves covering the topics of the 3DScavengers and SOUNDofICE EU projects. The universal character of vacuum and plasma methods allows for the deposition of an unprecedented variety of possibilities, including, organic (small-molecules, organic nanocomposites, polymeric layers), inorganic (metal and metal oxides), hybrid (hybrid perovskite) materials acting as conducting, semiconducting, dielectric, photo-absorbent, piezoelectric or plasmonic components in a multilayer or radial configuration. We will share the results accomplished during the last years in the field of energy harvesting (solar cells,[1-4] piezoelectric and triboelectric nanogenerators[5-7]), semi-transparent nanoelectrodes,[8] wetting [9], de-icing and anti-icing.[10-11]

References

Filippin, A., Sanchez-Valencia, J., Borras, A. et al. (2017) Nanoscale, 9:8133-8141.

Barranco, A., Borras, A., Sanchez-Valencia J. R. et al. (2020) Adv. Ener. Mater 10:1901524.

Castillo, J., Borras, A., Sanchez-Valencia J.R. et al. (2022) Adv. Mater. 34:2107739.

Obrero, J., Borras A., Barranco, A. (2022) Adv. Ener. Mater. 12:2200812.

Filippin, A. N., Borras, A. et al. (2019) Nano Energy 58:476-483.

García-Casas, X., Borras, A. et al. (2022) Nano Energy 91:106673.

García-Casas, X. Borras, A. et al. Patent application Self-powered triboelectric transductor device for drops and liquids. EP23382176.8

Castillo-Seoane, J., Borras, A. et al. (2021) Nanoscale 13:13882.

Montes, L., Borras, A. et al. (2021) Adv. Mater. Interf. 21:2100767.

Lopez-Santos, C., Borras, A. et al. (2019) Langmuir 35:16876.

Del Moral, J., Montes, L., Borras, A. et al. (2023) Adv. Funct. Mater. 2023, 2209421
Selective CO2 Electrolysis on Cu-on-MgO/Mg(OH)2 Catalyst through Enhanced CO2 Adsorption
Authors: Tsai Ding Huei , Wu Tung-Ta , Chueh Lu Yu , Wei-Chieh Liao , Yu Wen-Yueh , Pan Yung-Tin
Published: February 2024

Electrochemically drove CO2 reduction reaction (CO2RR) to value added products provides a promising route towards carbon neutrality. However, insufficient CO2RR performance and high energy barrier remain to be obstacles in process scale-up. In this work, the activation of CO2 molecules for the CO2RR is tackled by incorporating magnesium oxide/hydroxide as a support material for copper to form a supported catalyst, i.e., Cu-on-MgO/Mg(OH)2. Compare with commercial copper nanoparticles, significant improvement in CO2 activation, reflected by its onset potential, was observed. Under zero-gap reaction conditions, both the partial current density and Faradaic efficiency (FE) of C2 products was enhanced. From detailed materials characterization and in-situ temperature resolved infrared spectroscopy, valuable complementary information of the surface species can be observed. The impact of MgO to the local pH of the cathode will also be discussed. To encapsulate, we report a much enhanced CO2RR to C2 performance using the Cu-on-MgO/Mg(OH)2 catalyst and aim to decipher its role in CO2 activation.
(Keynote) Evidence of the Interplay of Temperature on Local and Global Battery Phenomena
Authors: Love Corey T. , Carter Rachel Elizabeth , Kingston Todd A. , Mukherjee Partha P. , Dubarry Matthieu , Waller Gordon Henry
Published: February 2024

Temperature is an important parameter in electrochemical processes and battery operation; for instance, open circuit voltage and resistance values of cells are temperature sensitive. Several recent studies have shown temperature within battery packs are not uniform. This non-uniformity of temperature produces localized thermal gradients within cells that can dictate cell construction, thermal management scheme, cell bussing, etc. Our research group has been working to understand how thermal gradients within battery cells effect material properties, electrochemical performance and stability. We have demonstrated through a range of electrochemical and materials characterization techniques, how dynamic external conditions, specifically thermal gradients and transients, can induce differing degradation modes of the positive and negative electrodes. The directionality and magnitude of thermal gradient dictate the degradation mode, whether loss of lithium inventory, loss of active material, etc.

We have also observed strong electrochemical-mechanical coupling the result of low temperature cycling, where lithium plating on the negative electrode causes a physical deformation and collapse of the cylindrical cell jellyroll. In this talk, we will present in-operando optical microscopy and X-ray computed tomography data to show how dynamic electrical and external thermal conditions can irreversibly effect the chemistry, structure and subsequent safety of lithium-ion battery materials, components and cells. Lastly, the importance of testing materials and cells outside of isothermal laboratory conditions in favor of operating under dynamic thermal conditions, to include austere and stressful operating conditions will be discussed.
A Study on Impedance Change of Lithium-Ion Batteries Depending on Charging Current Profile at Low Temperature
Authors: Lee Jaein , Ha Sang-Hyeon , Yoon Hyunki , Choi Yusong
Published: February 2024

Lithium-ion batteries(LIBs) are used in various portable electronic devices due to their advantages such as high energy density, power, and long lifespan. Therefore, various studies are being conducted to improve the capacity and power of LIBs and to increase their stability. As a result, LIBs has become a key component of electric vehicles(EVs) and hybrid vehicles(HEVs), which are rapidly increasing in recent years. However, even in these LIBs, the electrochemical reaction and the diffusion rate of lithium ions rapidly decrease at low temperatures, resulting in serious performance degradation. Therefore, low-temperature charging causes lithium plating and dendrite formation to reduce cell life and in severe cases cause cell rupture. In particulary, in the case of EVs and HEVs that are charged outdoors, low-temperature charging can cause serious problems such as battery rupture as well as shortened lifespan. Therefore, in this study, we analyze the effect of various charging techniques such as CC-CV, multi-stage CC, and pulse on the low-temperature impedance change of LIB and propose an optimal charging technique for stable charging.

AT first, test cells for the experiment were fabricated and activated, and then capacity and impedance were measured at room temperature. After that, the charge/discharge cycle experiment of each test cell was performed by applying the CC-CV, multi-step CC, and pulse charging methods at low temperature. After the cycle experiment, the capacity and impedance change of each test cell were measured at room temperature, and the correlation between the capacitance change and the impedance change was analyzed. As a result, the greatest change occurred in the resistance and capacitance components of the SEI (Solid Electrolyte Interface) layer, which is common to all charging methods. However, among the three charging methods, the pulse charging method had the smallest change in capacity and impedance. This is because the repetitive rest period of pulse charging gives relaxation time for diffusion of Li-ions. Next, morphological changes of the LIB anode were confirmed using a scanning electron microscope (SEM). As a result, it was confirmed that the lithium plating and dendrite generated during low-temperature charging additionally reacted with the electrolyte to form an additional SEI layer, thereby changing the thickness and shape of the SEI layer. Therefore, it was confirmed that the change of the SEI layer caused the LIB impedance change. Finally, we confirmed that a low current density or charging current with sufficient break time such as pulse charging is most effective in maintaining the endurance of LIBs at low temperatures.
Improvement of Electrochemical Performances of Electrochromic-Zinc Ion Batteries System Utilizing V4+-V2O5 As a Cathode
Authors: KIM Yonghan
Published: February 2024

Recently, many countries are practicing carbon neutrality to lower greenhouse gas emissions to "zero" by 2050. Therefore, zinc ion batteries (ZIBs) have been increasing attention as next-generation batteries due to low cost and high volumetric energy density. In addition, since ZIBs utilize a human-friendly water-based electrolyte, ZIBs has been proposed as an alternative to wearable energy storage systems. Above all, the electrochromic – ZIB system is gaining popularity as the next generation storage technology because it can visualize charging and discharging. Vanadium oxide(V2O5), one of the cathode materials of electrochromic ZIB, exhibits excellent electrochemical characteristics with excellent rate performance through intercalation in the layered structure. However, because of V2O5’s poor electronic and ionic conductivities, it is necessary to improve the structure improvement for increasing energy density.

To solve this problem, mixed multiple oxidation states of vanadium are essential to ZIB cathode. This mixed valence states are contributed to increase electrochemical performance and specific capacity.1 V4+-V2O5 exhibit higher electrochemical activity, faster ion transport, better electrical conductivity than Pure V2O5. Also, we can expect that V4+-V2O5 performs outstanding rate capability and long term-cyclic life.

In this study, we developed V4+-V2O5 based electrochromic-ZIB cathode to enhance electrochemical performance controlling the temperature for vanadium reduction heat treatment in H2 gas atmosphere. Furthermore, it will be determined whether vanadium oxide is suitable for electrochromic. Between the yellow V2O5 and the black Vanadium-based compounds, an appropriate point with excellent electrochemical and electrochromic properties will be found.
New Highly Graphitized N-Doped Carbon as a Robust Support for Pt Electrocatalysts
Authors: Yu Jong-Sung , Lee Ha-Young , Shin Cheol-Hwan
Published: February 2024

For polymer electrolyte membrane fuel cells (PEMFCs), the state-of-the-art electrocatalysts are based on Pt group metals deposited over electroconductive porous carbon support. However, current carbon supports suffer from carbon corrosion during repeated start-stop operations, causing performance degradation. We report a new strategy to produce highly graphitized porous carbon with controllable N-doping that uses low-temperature synthesis (650 ℃) from g-C3N4 carbon-nitrogen precursor with pyrolysis using Mg. The high graphiticity is confirmed by high-intensity 2D Raman peak with low ID/IG (0.57), pronounced graphitic XRD planes, and excellent conductivity. Without further post-treatment, this highly graphitized N-doped porous carbon (GNPC) material combines high pyrrolic-N content with high porosity. Supporting Pt on GNPC exhibits excellent oxygen reduction activity for PEMFC with greatly improved durability as proved by real-time loss measurements of Pt and carbon, the first to surpass the DOE 2025 durability targets for both catalyst and support. The Pt/GNPC prepared at 650 oC shows 32 and 24% drop in mass activity after accelerated durability tests of both electrocatalyst and support, respectively, which are less than DOE target of 40% loss. The atomistic basis for this durability is explained via quantum mechanics-based molecular dynamics simulations. Interestingly, it is found that pyrrolic-N strongly interacts with Pt, making the Pt catalyst more stable during fuel cell reaction. We expect that high porosity robust graphitized materials will lead to many other novel applications for electrocatalysis with durable carbon frameworks.
Visible Light Driven CO2 Photoreduction Using TiO2 Nanotube Arrays Embedded with Low Bandgap Carbon Nitride Nanoparticles
Authors: Vrushabendrakumar Damini , Alam Kazi , Chaulagain Narendra , Kumar Navneet , Shankar Karthik
Published: February 2024

The extraordinary thermal and photochemical stability, superior charge transport, and tunable band positions of graphitic carbon nitride (g-CN), which is constituted of elements that are plentiful on Earth, renders g-CN an important semiconductor photocatalyst for heterogeneous catalysis [1,2]. Despite these advantages, carbon nitride-based semiconductors do not function effectively as freestanding photocatalysts or photoelectrodes due to a rapid carrier recombination rate and a slightly wide bandgap that only enables them to capture blue and UV photons [3,4]. Anodically formed TiO2 nanotube arrays (TNTAs) are semiconducting wide bandgap scaffolds with excellent photocatalytic properties due to the intrinsic orthogonalization of charge generation/transport and charge transfer processes. Herein, we use a novel in situ electrophoretic anodization to embed low bandgap carbon nitride nanoparticles (CNNPs) in the walls of titania nanotubes. The likelihood of the CNNPs leaching off the TNTA photoanode during photoelectrochemical processes was eliminated by encapsulating CN inside a TiO2 matrix. CNNPs were formed by the thermal condensation polymerization of carbon nitride utilizing citric acid and urea as the precursors, and exhibited some unusual properties, including a lower bandgap of 2.1 eV, a highly redshifted fluorescence emission maximum at 2.35 eV, surface carboxylate groups, and the emergence of unique structural characteristics corresponding to amorphous yet graphitic carbon [5]. In contrast to bulk g-CN, which has a C:N ratio of 0.75, the CNNPs possessed an elevated C:N ratio as high as 1.87 at the surface. The additional carbon was found to be both amorphous and graphitic, although the structural characteristics of g-CN were mostly unaffected, as validated by diffractometric and spectroscopic data. Even in the absence of a sacrificial agent, the CNNP@TNT nanocomposite demonstrated enhanced performance in sunlight-driven CO2 photoreduction. When compared to the freestanding TNT photocatalyst, the CO yield of photoreduction for the CN@TNT hybrid was more than three times higher. UV-filtered illumination of the CNNP@TNT heterojunction photocatalyst generated appreciable quantities of methane and CO (3.41 and 8.78 μmolg–1h–1 respectively). In situ electrophoretic anodization is an innovative approach to incorporate semiconductor quantum dots into TiO2 nanotubes or other electrochemically grown nanostructures.

REFERENCES

1. Kessler, F. K. et al., Nature Reviews Materials (2017) 2 (6), 1.

2. Chaulagain, N. et al., ACS Applied Materials & Interfaces (2022) 14 (21), pp.

24309-24320.

3. Kumar, P. et al., Advanced Optical Materials (2020) 8 (4), Art. No. 1901275.

4. Fu, J. et al., Advanced Energy Materials (2018) 8 (3), Art. No. 1701503.

5. Alam, K.M. et al., Chemical Engineering Journal (2023) 456, Art. No. 141067.
3D Printed Carbon Framework with the Graphene Aerogel for Microbial Fuel Cell Application
Authors: Nikolaev Konstantin G. , Wu Jiqiang , Leng Xuanye , Ivanov Artemii S. , Vazquez Ricardo J. , McCuskey Samantha R. , Bazan Guillermo C. , Novoselov Kostya S. , Andreeva Daria V.
Published: February 2024

There is a high interest in living organism-compatible materials associated with electrically active interfaces. Bacteria/electrode interfaces implement smart, functional systems with responses, based on which it is possible to elaborate self-regulating energy generation systems. Carbon materials have a number of advantages, such as biocompatibility, low electrical resistance, and the possibility of increasing the electrode surface on an industrial scale. The most promising approach for the industrial production of electrodes is 3D printing. We propose a 3D-printed carbon electrode – a novel lightweight material for electrodes in bioelectrochemical systems for efficient bioelectricity utilization.

The pyrolytic process for manufacturing carbon electrodes is promising for upscaling and industrial applications. However, there is a problem of volume loss when 3D-printed polymers are pyrolyzed in an inert environment. We propose a new strategy for the thermal treatment of 3D-printed polymers that allow for reduced volume loss under pyrolytic carbonization. In addition, to achieve a higher electrode surface area, the graphene aerogel could be impregnated into the 3D-printed scaffolds. Chemical modification of graphene surface can enhance biocompatibility. Specifically, the oxidation of graphene leads to forming a hydrophilic and biocompatible material. We tune graphene hydrophilic properties and electrical conductivity via control over the thermal reduction of the oxidized form of graphene–graphene oxide1.

Such sponge morphology affords 3D-printed carbon scaffolds an excellent lightweight host scaffold for microorganisms, in which the graphene nanowalls are homogeneously occupied by S. oneidensis MR-1. We demonstrate a novel sustainable method to produce graphene-based lightweight 3D printed electrode materials for green energy production from biomass. The proposed technology creates the opportunity for novel, innovative, disruptive graphene applications that can lead to the establishment of new energy-related industries and facilitate many startups in the ecosystem.

Acknowledgments

This work was supported by the Ministry of Education (Singapore) through the Research Centre of Excellence program (grant EDUN C-33-18-279-V12, I-FIM).

References

Xuanye Leng, Ricardo J. Vazquez, Samantha R. McCuskey, Glenn Quek, Yude Su, Konstantin G. Nikolaev, Mariana C.F. Costa, Siyu Chen, Musen Chen, Kou Yang, Jinpei Zhao, Mo Lin, Zhaolong Chen, Guillermo C. Bazan, Kostya S. Novoselov, Daria V. Andreeva, Carbon, 205, 2023, 33-39.
A Study on MXene/Graphene Composite Coatings for Electromagnetic Shielding Paints
Authors: Kim Young-Seok , Lee Byoung Wan
Published: February 2024

In recent years, rapid advancements in digital and semiconductor technology have made it possible to miniaturize electronic devices, increase their speed, and provide broadband capabilities. However, the problem of malfunctioning due to even minor electromagnetic interference has become increasingly common. The increase in electromagnetic wave density creates an unfavorable electromagnetic environment, which applies not only to civilians but also military weapons and battlefields. In this study, we conducted research on a new composite material-based electromagnetic shielding paint to reduce communication noise. We introduced MXene/Graphene and nano organic and inorganic particles and analyzed the dispersion characteristics of the composite material and the optimal coating structure for using it as a coating pigment.
Bioactive Ion-Based Switchable Supercapacitors
Authors: Li Panlong , Grothe Julia , Kaskel Stefan
Published: February 2024

Switchable supercapacitors enable a reversible electrically driven uptake and release of bioactive ions by polarizing nanoporous carbon electrodes. In this work we demonstrate the first example of a bioactive ion-based switchable supercapacitor. Based on choline chloride and nanoporous carbons with defined porosity we unravel the mechanism of physisorption vs. electrosorption by nuclear magnetic resonance, Raman, and impedance spectroscopy. Weak physisorption leads to pronounced electrically driven electrolyte depletion enabling the release and capture of electrolyte ions in highly controllable and reversible manner. A new 4-terminal device structure is proposed, with a main capacitor and a smaller inserted detective capacitor for monitoring bioactive ions electrosorption in situ. Controlling the ion concentration in a printed switchable supercapacitor based on bioactive ions realizes switching down to 8.3% residual capacity.

The exploration of electrically driven adsorption mechanisms in printable microdevices will open an avenue of manipulating bioactive ions for the further application of drug delivery, neuromodulation, or neuromorphic devices.

Figure 1
Sustainable Laser Induced Supercapacitors from Cork Natural Substrates
Authors: Imbrogno Alessandra , Islam Jahidul , Santillo Chiara , Castaldo Rachele , Sygellou Lamprini , Larrigy Cathal , Murray Richard , Vaughan Eoghan , Hoque Khairul Md , Quinn Aidan J , Iacopino Daniela
Published: February 2024

A novel type of eco-friendly and cost-effective supercapacitor has been developed by fabricating interdigitated and squared supercapacitors made of porous graphitic carbon electrodes and Polyvinyl alcohol (PVA) electrolyte. The electrodes were fabricated using a simple, fast, and low-cost laser engraving process, using visible irradiation wavelengths (450 nm) and performed under ambient conditions, resulting in highly three-dimensional, electrically conductive, and porous graphitic carbon structures.

By adjusting the laser power and wavelength, it was possible to produce electrode materials with highly porous and high surface area morphology, which are promising for electrochemical applications. Spectral investigation using Raman and FTIR spectroscopies confirmed the formation of graphitic carbon structures and the full conversion of the cork precursor under visible laser irradiation.

The obtained electrodes exhibited excellent supercapacitive behavior when exposed to a PVA electrolyte, achieving a specific areal capacitance of up to 11.24 mF/cm2 with PVA at 30% laser power. The supercapacitive properties showed excellent stability over time, with no significant loss after 10000 charge/discharge cycles.

To evaluate the performance of the new supercapacitors, linear electrodes were used as working electrodes in a three-electrode configuration electrochemical cell. The electrodes showed diffusion-limited electrochemical behavior with fast heterogeneous electron transfer rates (HET), which was superior to that of traditional glassy carbon electrodes.

The innovative and efficient electrode fabrication method presented in this study, which utilizes low-cost instrumentation, environmentally friendly fabrication methods, and Earth-abundant precursor materials, shows great promise for producing large-scale "green" electrochemical sensing platforms and devices in the future.
Maternal Smoking and Risk of Hypertensive Disorders of Pregnancy: Effect Modification by Body Mass Index and Gestational Weight Gain
Authors: Dunn Morgan C. , Ananth Cande V. , Rosen Todd
Published: February 2024

BACKGROUND:

Although smoking cigarettes has been shown to have a protective effect on preeclampsia, quitting smoking also results in weight gain. Weight gain leading to an obese body mass index is a risk factor for hypertensive disorders of pregnancy (HDP).

METHODS:

The objective of this study was to explore the relationship between smoking status, body mass index, and gestational weight gain on the risk of HDP. A cross-sectional analysis was performed utilizing US birth certificate data. We examined HDP risks in relation to maternal smoking, body mass index, and gestational weight gain. Associations were expressed as rate ratios with 95% CIs and adjusted for potential confounders. Clinically important outcomes of smoking throughout pregnancy were also evaluated.

RESULTS:

Of the 22 191 568 women studied, HDP rates among nonsmokers, those who quit smoking, and persistent smokers were 6.8%, 8.6%, and 7.0%, respectively. The rate ratio of HDP was higher for women who quit smoking, especially evident among those with excessive gestational weight gain. Corrections for exposure misclassification and unmeasured confounding strengthened the associations among women who quit smoking. There was an almost 6-fold increase in the rate of stillbirth for persistent smokers (2.3%) compared with those who quit smoking (0.4%) and nonsmokers (0.4%).

CONCLUSIONS:

Women who quit smoking during pregnancy were more likely to gain excessive weight and develop HDP. Although quitting smoking during pregnancy may be associated with an increase in the risk of HDP, it is also associated with a reduced risk of stillbirth. Pregnant women counseled to quit smoking should also receive counseling on nutrition and exercise to prevent excessive gestational weight gain.
The External Validity of College Remediation Effects: Caveats about Compliers in Fuzzy-discontinuity Designs
Authors: Cordes Lucy , McEwan Patrick , Weerapana Akila
Published: February 2024

Fuzzy regression-discontinuity evaluations of college remediation often find negative and null estimates of local average treatments effects (LATEs), but with substantial heterogeneity. We find that a remedial quantitative skills course at Wellesley College has a modestly positive LATE on participation in mathematically intensive fields of study—including the sciences, mathematics, and economics courses. Yet, LATEs are a weighted average of average causal effects (at the passing cutoff) in two principal strata: students who voluntarily comply with remediation, and those who are coerced to comply after scoring below the cutoff on an optional retest. In the retest sample, we show that average causal effects are close to zero among (1) coerced compliers, and (2) never-takers. By implication, there are even larger effects among a smaller group of voluntary compliers at the cutoff. The results help interpret the mixed findings in the literature, in which compliance varies widely, and demonstrate methods for assessing external validity in fuzzy-discontinuity designs.
“He would Thunder from an Artificial Sky, as Salmoneus”: Constantine Komnenodoukas’ Patronage of a ‘Persian’ soufa in Naupaktos (ca. 1220)
Authors: Riccardi Lorenzo
Published: February 2024

Around 1220, Constantine Komnenodoukas undertook the construction of an unconventional building in Naupaktos, Greece, referred to as a ‘Persian’ soufa. Information on this construction is contained in a letter written by the city’s metropolitan, John Apokaukos, who maintained an adversarial rapport with him. The soufa is described as a rectangular structure with two levels. In the higher one, reserved for Constantine and his retinue, a throne shaped as an episcopal throne was placed. Conversely, the lower level accommodated more humble guests who could only listen to him thundering like Salmoneus from an artificial sky. This architectural venture served as a symbolic manifestation of Constantine’s secular authority, deliberately positioned in contrast to the ecclesiastical figure of the bishop. Noteworthy is Constantine’s deliberate appropriation of ideas, forms, and language acquired during his sojourn in Asia Minor several years before. The resulting structure stands as a singular manifestation, representing a distinctive historical juncture influenced by the personality of Constantine Komnenodoukas, wherein elements of both Byzantine and Islamic art are combined.