bluuebunny/crossref_metadata_2025 huggingface dataset:
Accessing Cation and Anion Redox in a 1-D Iron-Chalcogenide, Na3Fe2S4-XSex (x = 0, 2, & 4), in Na-Ion Batteries
Authors: Sundaramoorthy Santhoshkumar , Bhattacharya Sutapa , Choudhury Amitava
Published: August 2024

The utilization of anionic redox activity is gaining significant interest in chalcogen based alkali-ion batteries. In this study, we are reporting reversible Na-ion (de)intercalation in one-dimensional structure of Na3Fe2S4-xSex (x = 0, 2, and 4). The crystal structure of Na3Fe0.5
2+Fe0.5
3+Q4 (Q = S and Se) can be visualized as a mixed valent iron, Fe2+/Fe3+
, forming infinite edge-shared chain of FeQ
4 tetrahedra with Na-ion residing in the interchain voids. While cycling the cathodes within a potential range of 1.5 – 2.5 V vs. Na/Na+, we could reversibly (de)intercalate one mole of Na from the structure. Mössbauer spectroscopy reveals a complete Fe2+ to Fe3+ oxidation in all the charged samples. Substitution of less electronegative Se2– in the structure systematically lowers the Fe2+/3+ redox couple during cycling. After 100 cycles at 1C rate, the cathode retains 83 % of its initial reversible capacity. While cycling the same cathode at a higher voltage range of 1.5 – 3.0 V, we observed a flat plateau profile at ~2.6 V with capacity reaching 255 mAh/g for Na3Fe2S4 cathode. This high capacity can be directly attributed to the anion oxidation for the charge compensation process during ~3.0 Na-ion deintercalation as supported by XPS analysis. The flat plateau profile further decreases from 2.6 to 2.5 V with the substitution of Se2–. The GITT results show two distinct kinetic behavior for the cation (fast) and anion (sluggish) redox. The decoupling of cation and anion redox in this system can enable us to understand and optimize the utilization of both redox chemistries to achieve a high energy density cathode.
On the Correlation of Kramers-Kronig (KK) Analysis and Non-Linear Harmonic Analysis (NHA)
Authors: Katırcı Gökberk , Civan Fazlı Eren , Ülgüt Burak
Published: August 2024

Primary lithium batteries are known for their elevated volumetric and gravimetric energy densities and production cost efficiency. Within this category, lithium thionyl chloride (Li/SOCl2) batteries exhibit a constant discharge voltage (~3.6 V) and a broad operational temperature range (-50ᵒC to 80ᵒC). Moreover, forming a LiCl passivation layer on the metallic Li anode can extend its shelf-life up to 20 years at optimal storage temperature. These characteristics render lithium thionyl chloride batteries applicable in military and security applications, microcomputers, measurement devices, and medical instruments. Therefore, the characterization of lithium thionyl chloride batteries accurately has the utmost importance. Understanding the critical electrochemical processes that occur inside the battery without damaging or disassembling the cell requires delicate techniques.

EIS has emerged as a non-destructive and in-situ measurement technique with increasing popularity. Essential battery properties can be derived from EIS data. The credibility of EIS data, considering linearity, causality, and stability, can be verified through Kramers-Kronig relations. The obtained spectrum is fitted with an optimal number of Voigt elements (RC components in parallel)[1]. Given the linearity and stability of these individual Voigt elements, the entire spectrum should exhibit linearity if it is Kramers-Kronig compatible[2].

Non-linear harmonic analysis (NHA) is a complementary technique to EIS, wherein the response signal undergoes conversion from the time domain to the frequency domain through Fast Fourier Transformation (FFT). While EIS employs a single-phased pure sinusoidal signal as the input, the response includes a fundamental frequency and harmonics at integer frequencies of this fundamental response signal. NHA can be utilized in the diagnosis of non-linear, non-stationary situations alongside the identification of drift and initial transients.

This study first explains a new EIS measurement method for Li/SOCl2 batteries and Li/SOCl2/SO2Cl2 mixture batteries. The new method describes the solid electrolyte interface (SEI) stability of the batteries and the modifications needed to get KK-compatible results. After that, the equivalent circuit fits applied to the acquired spectra. Essential battery parameters such as solution resistance, charge transfer resistance, and double-layer capacitance were calculated. Kramers-Kronig analysis of the batteries was conducted, and the residuals of the fits were investigated. Subsequently, the NHA of the batteries was examined and compared to the Kramers-Kronig residuals. A correlation between the residuals and NHA of the batteries was extended based on the terms "KK-compatible" and "non-KK-compatible" in comparing KK-residuals and NHA results.

[1] Boukamp, B. A. , Journal of the Electrochemical Society 142.6 (1995): 1885.

[2] Agarwal, et al., Journal of the Electrochemical Society 142.12 (1995): 4159.

Figure 1
Addressing Mass Conservation in Two-Dimensional Modeling of Lithium Metal Batteries with Electrochemically Plated/Stripped Interfaces
Authors: Mishra Lubhani , Jang Taejin , Subramaniam Akshay , Uppaluri Maitri , Ramadesigan Venkatasailanathan , Garrick Taylor R. , Subramanian Venkat R.
Published: August 2024

Several previous studies have aimed to develop mathematical models based on the moving boundary approach for predicting changes in lithium morphology during the cycling of lithium metal batteries under different operating conditions. These modeling frameworks play a crucial role in enhancing our fundamental understanding of the transport and reaction mechanisms and guide experimentalists in developing safer and more efficient lithium metal anodes. In this work, using a simple two-dimensional model for the lithium metal battery, we aim to bring attention to the bulk convection in the liquid electrolytes induced by the movement of the lithium metal surface modeled as a moving boundary. The back-and-forth motion of the lithium metal surface during the plating and stripping of lithium introduces a weak fluid motion in the liquid electrolyte that should be incorporated in the model equations and corresponding boundary conditions (Figure 1). The results for the electrochemical signatures and morphology evolution thus obtained by solving a coupled fluid model are compared with the case where the velocity distribution in the liquid electrolyte is ignored. This work extends our previously reported perspective on the convective flux correction to rectify the mass conservation failures at moving boundaries in one-dimensional models to two dimensions. This careful implementation of the correct boundary conditions ensures the mass conservation of lithium in two-dimensional simulations for predicting the morphological evolution of lithium metal electrodes over cycles. These revised battery models with accurate mass and charge conservation are crucial for predicting the performance of the battery over cycles. Additionally, these relative fluxes at the moving and fixed boundaries are sometimes ignored by assuming a bulk concentration condition at the far end, especially at the cathode/separator interface. While it may not affect overpotential signatures at the anode, it leads to mass conservation issues with implications for the accuracy of cycling simulations. Thus, with the help of a two-dimensional electro-convection model, this study addresses the role of bulk convection in liquid electrolytes and the importance of ensuring mass conservation in lithium metal battery models.

References:

T. Jang et al., J. Electrochem. Soc.,
170(11), 110516 (2023).

T. Jang et al., J. Electrochem. Soc.,
169(8), 080516 (2023).

T. Jang et al., ECS Trans, 104(1), 131 (2021).

L. Mishra et al., J Electrochem Soc, 168(9), 092502 (2021).

Figure 1
Analyzing the Doping Mechanism of High-Valence Element in Ni-Rich Cathode Materials
Authors: Kim Myoung-Chan , Park Nam-Yung , Sun Yang-Kook
Published: August 2024

Layered cathode materials, LiMO2 (M=Ni, Co,Mn, or Al), with a high nickel content are promising cathode materials owing to their near-theoretical specific capacity. However, the inherent chemical and structural instabilities of Ni-rich cathodes lead to several problems, including rapid capacity fading, thermal instability, gas evolution, and safety concerns.1

Introducing additional elements into Ni-rich cathodes is an essential strategy for addressing the instability of the cathode material. Conventionally, this doping strategy considers only the incorporation of additional elements into the bulk structure of the cathode in terms of fortifying the crystal structure.2 However, high-valence elements are likely to be insoluble in the crystal structure, resulting in accumulation along the interparticle boundaries.3 Herein, a new mechanism for doping high-valence elements into Ni-rich cathodes and their effects on the morphology and crystal structure are investigated by calcining LiNiO2 (LNO) and X-doped LNO cathodes (X=Al, Nb, Ta, and Mo) at various temperatures. Operando X-ray diffraction analysis reveals that the temperature at which the content of Li-X-O compounds declines is higher for the dopants with high oxidation states, reinforcing segregation at the grain boundary. Thus, the highly aligned microstructure and high crystallinity of the LNO cathode are maintained over a wide calcination temperature range after doping with high-valence elements, enhancing the electrochemical performance.

References:

[1] N.-Y. Park, G.-T. Park, S.-B. Kim, W. Jung, B.-C. Park, Y.-K. Sun, ACS Energy Lett.
2022,7, 2362.

[2] X. Ou, T. Liu, W. Zhong, X. Fan, X. Guo, X. Huang, L. Cao, J. Hu, B. Zhang, Y. S. Chu, G. Hu, Z. Lin, M. Dahbi, J. Alami, K. Amine, C. Yang, J. Lu, Nat. Commun.
2022,13, 2319.

[3] G.-T. Park, D. R. Yoon, U.-H. Kim, B. Namkoong, J. Lee, M. M. Wang, A. C. Lee, X. W. Gu, W. C. Chueh, C. S. Yoon, Y.-K. Sun, Energy Environ.Sci.
2021,14, 6616.
Carbon-Coated Mesoporous Silica Nano-Quills from Bioderived Cellulosic Templates for Low-Cost Anodes
Authors: Chen Nancy , Sabet Morteza , Clemons Craig M. , Rao Apparao M. , Pilla Srikanth
Published: August 2024

The escalating global energy demands, driven by population growth and the electrification of transportation, have positioned rechargeable lithium-ion batteries (LIBs) as critical components in phasing out traditional fuel-based technologies. To date, several high-capacity active materials have been developed to replace current graphite-based anodes for boosting the energy density of LIBs. Silicon dioxide (SiO2, or silica) has emerged as a promising alternative, with a high theoretical capacity of 1965 mAh g-1, five times higher than conventional graphite, along with a comparatively smaller volume change than elemental Si during battery cycling. In this study, we report a patented synthesis process that harnesses wood-derived cellulose nanocrystals (CNCs) to craft a unique three-dimensional (3D) silica architecture for developing low-cost LIB anodes. Our cost-effective method yields a mesoporous silica material, termed silica nano-quill (SilicaNQ), with distinctive hollow 1D arms. In addition, we propose a direct annealing strategy for transforming CNC templates into a conformal carbon coating to fabricate SilicaNQ@C powder material. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provided a detailed exploration of the elemental composition and the bonding states at the atomic level. Anodes comprising SilicaNQ@C active material delivered a stable reversible capacity of 1030 mAh g-1 after cycling at 200 mA g-1 for 200 cycles. We performed X-ray diffraction (XRD) measurements on SilicaNQ@C half cells to identify phase changes at various state-of-charge levels and explore the evolution of interface components over cycling.
Influences on Reliable Capacity Measurements of Hard Carbon in Highly Loaded Electrodes
Authors: Müller Cedric , Wang Zhengqi , Hofmann Andreas , Stüble Pirmin , Liu-Théato Xinyang , Klemens Julian , Smith Anna
Published: August 2024

Lithium-ion batteries (LIBs) are the current state of the art energy storage technology. However, to tackle the steady increasing demand for clean but also sustainable energy, other complementary cell chemistries are gaining significant importance. Sodium-ion batteries (NIBs) are considered to be a drop-in technology that can benefit from the knowledge about processing of LIBs and its existing manufacturing structures.

For the development of a sodium-ion full-cell, commercially available hard carbon (HC) as an anode material was characterized within a half-cell setup. On the one hand, those measurements are essential to characterize individual electrodes in order to obtain electrochemical information that is needed to set up the full cell, e.g. balancing. On the other hand, the exact determination of the HC capacity is prone to errors, mainly due to the cut-off potential being close to 0 V against metallic sodium. This behavior and also electrolyte degradation in presence of elemental sodium were studied.

It has been found that the potential of the current carrying sodium counter electrode in half-cells is not stable, resulting in measurement inaccuracies, particularly at elevated C-rates when charging is controlled by a cut-off potential. On the contrary, by using a three-electrode setup, the current-free reference electrode provides stable cut-off conditions. An improved setup for half-cell measurements is suggested to obtain reliable and reproducible capacity readings for HC anodes with an areal capacity of up to 2.4 mAh/cm².

Figure
: Schematic overview about the investigated control voltages and their effect on the electrochemical performance.
[1]

The initial coulombic efficiency (ICE) of HC is a current challenge because it is relatively low at about 80% and it can vary for different HC materials. Therefore, precise measurements are a necessity to develop HC materials with higher ICEs.

Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC 2154.

[1] Müller, C., Wang, Z., Hofmann, A., Stüble, P., Liu-Théato, X., Klemens, J., Smith, A., “Influences on Reliable Capacity Measurements of Hard Carbon in Highly Loaded Electrodes” Batteries & Supercaps 2023, e202300322.

Figure 1
Measurement of Li-Ion Self-Diffusion in Laser Structured Electrodes
Authors: Tambio Sacris Jeru , Deschamps Michael , Pfleging Wilhelm
Published: August 2024

It is generally stated that a limiting factor in fast charging and high-power discharging of lithium-ion batteries (LiB) stems from the diffusion kinetics of Li+ in the electrode pore network. Numerous approaches in enabling fast charging of LiBs include active material development, electrolytes with high ionic conductivity and the management of the charging and discharging temperature. Another promising method is laser micro structuring to modify the electrode architecture regarding an enhanced lithium-ion diffusion kinetics. An increased high-rate capability and boost in cell lifetime have been demonstrated with such 3D electrodes [1, 2] but the related mechanisms leading to a substantial impact to diffusion kinetics are still poorly understood. Furthermore, it is imperative to find an optimal ablation pattern with regard to the desired application scenario that minimizes active mass loss in order to create the economic basis for efficient upscaling of the process.

Nuclear Magnetic Resonance (NMR) measurements of longitudinal (T1) and transverse relaxation times (T2), as well as the T2/T2 exchange, are routinely used for the identification of different molecular species. The exchange NMR experiment is a well-known technique for studying local environments of nuclei such as liquids in pores and approximating their shapes and sizes [3]. The evolution of the transverse relaxation rate (T2) of a probed nuclei allows to determine if the specie is confined (shorter T2) or in liquid bulk (longer T2). In this work, so-called Exchange Nuclear Magnetic Resonance (T2/T2 exchange or EXSY), is conceptualized to study the impact of laser generated 3D patterns in pore self-diffusion of electrolyte species.

Exchange NMR and T1 and T2 measurements were realized at various soaking times and electrolyte amounts for the following electrolyte species: Li+, PF6
-, ethyl carbonate (EC), and ethyl methyl carbonate (EMC), using laser structured, graphite-based electrodes casted on non-metallic substrates (to reduce RF interference). 2D exchange maps show the presence of confined species as well as the approximation of the diffusion properties. Using isotope exchange experiments with 6Li enriched electrolyte, concentration maps revealed the rate of 6LiPF6 intrusion into 7LiPF6 rich pre-soaked electrodes. The impact of laser generated 3D patterns in pore diffusion will be discussed in detail.

[1]. Zheng, Y. et al. 3D silicon/graphite composite electrodes for high-energy lithium-ion batteries. Electrochim. Acta
317, 502–508 (2019).

[2]. Smyrek, P., Pröll, J., Rakebrandt, J.-H., Seifert, H. J. & Pfleging, W. Manufacturing of advanced Li(NiMnCo)O2 electrodes for lithium-ion batteries . Laser-based Micro- Nanoprocessing IX
9351, 93511D (2015).

[3]. Mitchell, J. et al. Validation of NMR relaxation exchange time measurements in porous media. J. Chem. Phys.
127, (2007).
A Low-Cost Iron-Based Substrate for Alkaline Battery Electrodes
Authors: Maniyanganam Ahamed Irshad , Mitra Debanjan , Rajan A Sundar , Trinh P , Balasubramanian Mahalingam , Tomar Yeshvi , Prakash G. K. Surya G. K. , Narayan Sri
Published: August 2024

The nickel foam current collector adds significantly to the cost of the positive electrode of nickel-based alkaline batteries.1 Iron is roughly 40 times less expensive than nickel; but iron corrodes at the operating potential of the nickel electrode at pH 14 or higher.2 Thus, for an iron substrate to be viable, it should be protected from anodic corrosion in alkali and the surface must be electrically conducting. We found that a 100 nm thick thermal coating of cobalt ferrite protects iron from corrosion. The protected iron substrate was stable for 1000 h even when anodically polarized at 10 mA cm−2 in 30% potassium hydroxide battery electrolyte.3 The electrical conductivity of the coating could be improved by the incorporation of lithium-ions. The enhanced conductivity was attributed to an increase in the population of Co3+ in the spinel lattice as evidenced from XPS and XAS analyses.4 The nickel electrode on such an inexpensive iron-based substrate exhibited a specific capacity of 0.25 Ah g−1 at C/5 discharge rate, comparable to a nickel hydroxide electrode on expensive nickel foam. The electrode also exhibited no noticeable degradation for 150 cycles at C/2 rate. This robust and economical iron substrate thus presents a unique opportunity for reducing the cost of the nickel electrode in aqueous alkaline batteries.

References:

(1). J. Chen, D. H. Bradhurst, S. X. Dou, and H. K. Liu, J. Electrochem. Soc., 146, 3606 (1999)

(2). B. Beverskog and I. Puigdomenech, Corros. Sci., 38, 212 (1996)

(3). A. Irshad, D. Mitra, A. Sundar Rajan, P. Trinh, M. Balasubramanian, and S. R. Narayanan, J. Electrochem, Soc,, 167, 020543 (2020)

(4). V. Pralong, A. D. Vidal, B. Beaudoin, J. B. Leriche, and J. M. Tarascon, J. Electrochem. Soc., 147, 1306 (2000)

Figure 1
Regulating Sn Metal Growth Towards Highly Reversible Anode in Aqueous Acidic Batteries
Authors: Zhang Haozhe , Lu Xihong , Meng Shirley
Published: August 2024

Safe and cost-effective aqueous acidic batteries (AABs) offer substantial promise for renewable energy storage, as it have the potential to achieve greater energy and power density by utilizing non-metal hydrate protons as charge carriers.1 However, most of traditional aqueous anode electrodes (Zn, Fe, etc.) have incompatibility with AABs due to the instability in acid, resulting in the quite limited choice of anode materials in acidic environment.

In prior research, we successfully demonstrated that Sn metal can serve as a highly suitable anode material for AABs.2 This is attributed to its comparatively high overpotential for the hydrogen evolution reaction (HER), substantial theoretical capacity (451.6 mAh g−1), and negative redox potential (−0.14 V vs. SHE).3 The critical issue is that Sn tends to form polyhedral particles during the electro-deposition due to the small difference in surface energy between different planes.4 Along with the increase of capacity, the polyhedron Sn particles may become detach and fragment, ultimately leading to the formation of inactive, or dead Sn, which significantly impacts the cycling stability of Sn anode and even cause severe HER.

We will present our efforts of developing reversible Sn anode for AABs by regulating Sn metal growth. Our first work applies interfacial alloying regulation to achieve smaller grain size and more uniform Sn deposition by higher propensity for nucleation and Sn migration energy barrier, thus increased the anode reversibility. The following work successfully selected a HER-inert crystal plane and achieved its preferential growth used cationic surfactants electrolyte additive. A dense and compact Sn film is obtained by adjusting the adsorbed species on the Sn surface, and no dead Sn was observed after cycling. Based on these regulated Sn metal anodes, we demonstrated several Sn-based AABs (MnO2//Sn, PbO2//Sn, etc.), with promising performance on output voltages, specific energy densities, kinetics, and lifespans.

References

X. Wu, J. J. Hong, W. Shin, L. Ma, T. Liu, X. Bi, Y. Yuan, Y. Qi, T. W. Surta, W. Huang, J. Neuefeind, T. Wu, P. A. Greaney, J. Lu, X. Ji. Nat. Energy
2019, 4, 123-130.

H. Zhang, D. Xu, F. Yang, J. Xie, Q. Liu, D. Liu, M. Zhang, X. Lu, Y. S. Meng. Joule
2023, 7, 971-985.

W. Zhou, S. Ding, D. Zhao, D. Chao. Joule
2023, 7, 1099-1110.

Y. Yao, Z. Wang, Z. Li, and Y. Lu. Adv. Mater.
2021, 33, 2008095.
Comparing Electrode Overpotential Contributions in Vrfbs Amongst Multiple Techniques
Authors: Bachman Ridge M. , Pate Callaway , Owuor Peter , Khan Abdullah , Hall Derek M.
Published: August 2024

Redox flow batteries (RFBs) offer a potential remedy for the escalating need for energy storage amid the ongoing transition from carbon-intensive fossil energy to renewable energy sources. Yet, many RFB chemistries are shown to have low energy efficiencies which can be attributed, in part, to ineffective electrode materials. Identifying overpotential contributions from electrodes under operating conditions is a key step in understanding how to design better RFB electrodes Previously, three-electrode setups using rotating disk electrodes (RDE) were the effective technique at isolating overpotentials; however, this can only be accomplished by looking at one side of the RFB at a time. RDEs do not easily replicate the operational conditions of a power cell or the porous nature of carbon electrodes used in RFBs. Alongside the normal operation of an RFB, symmetry cells are another approach that can be utilized in quantifying the performance of electrodes. The advantage of a symmetrical cell setup allows us to monitor the overpotential contributions of two different electrodes in the same electrolyte concurrently. Membrane-based reference electrodes (MBRE), and other reference electrode integration concepts, allow us to use three-electrode techniques in operational RFB power cells. As a case study, we examined the effect of oxidative electrode treatments on the positive and negative side of the VRFB using multiple methods. While other studies have shown that an untreated negative electrode may be the key inhibitor in VRFB performance, we have quantified the overpotential at 50% state of charge to be 194 mV when 50 mA cm-2 is applied. After an oxidative treatment is applied to the negative electrode, the overpotential is reduced to 111 mV. Applying this to other techniques, we can compare the effectiveness of a non-symmetry cell setup vs. a symmetry cell setup, which displayed that oxidative treatment techniques appear to have an opposite effect on the positive electrode. A treated-positive electrode shows an overpotential of around 100 mV whereas an untreated-positive electrode only contributes 15 mV less of overpotential. These findings are further compared using common reference electrodes placed in the electrolyte tank, providing insights into the effectiveness of power cell techniques in improving RFB electrode performance.
Designing Interphases in Zn and Al Aqueous Electrolytes
Authors: Pastel Glenn , Pollard Travis , Chen Ying , Ma Lin , Liu Qian , Zhang Zhengcheng , Borodin Oleg , Schroeder Marshall A. , Xu Kang
Published: August 2024

This talk will cover two recent studies led by the Army Research Laboratory investigating interphase formation and cation solvation in zinc and aluminum aqueous electrolytes, respectively. In the former, two co-cations were carefully designed to offer distinct, complementary improvements in aqueous Zn electrolytes: a partially fluorinated pyrrolidinium cation effectively suppresses parasitic reactions such as hydrogen evolution (< 6 µA cm-2), and an ether-functionalized ammonium cation inhibits dendrite formation (almost 10 Ah cm-2 cumulative capacity, > 1 year, Zn||Zn). In the later, transient electrostatic hydrolysis of Al-OH2 ligands, without Al-OTf contact ion pairs, leads to insufficient reductive stability for rechargeable metal anodes. These contrasting systems provide helpful guidance for designing aqueous electrolytes with energy-dense multivalent metal anodes.
(Invited) Interactions of Open Cage Fullerenes with Metal Complexes
Authors: Balch Alan , Gralinski Steven , Baldauf Lilia
Published: August 2024

Open-cage fullerenes have complex structures with an the outer surface that generally contains Lewis basic sites produced by the cage opening reactions as well as an inner void that could accommodate a metal ion. This talk will discuss the reactions of open-cage fullerenes with metal complexes and highlight instances where unanticipated chemical reactions accompany the addition of metal complexes to open-cage fullerenes.

Figure 1
(Invited) Impact of Anchors on the Photophysical Processes in Water-Soluble Fullerene Conjugates
Authors: Ma Yue , Persi Lorenzo , Yamakoshi Yoko
Published: August 2024

Fullerenes are excellent acceptors in both photoinduced electron- and energy-transfer reactions. Many studies on the photophysical processes of fullerenes have been reported in the last decades, especially aiming towards the development of electronic devices. However, only a few studies have been reported on biocompatible fullerene systems, mainly due to the extremely low solubility of C60 in both water and water-miscible solvents. In our previous studies, we reported the synthesis of fullerene-PEG conjugates and demonstrated their ability for photoinduced DNA damage and ROS generation upon visible light irradiation.2

In this work, we investigated the effect of the water-soluble anchors on the photophysical properties of fullerene molecules. The generation of ROSs in water-soluble fullerene-peptide conjugates were tested by electron paramagnetic resonance (EPR) methods in comparison to previously reported fullerene-PEG conjugates above. To better understand the mechanism in ROS generation, a comprehensive investigation was performed by transient absorption spectroscopic data, encompassing the dynamics of photon absorption, exciton formation, and charge transfer mechanisms. Additionally, insights derived from density functional theory (DFT) calculations and in vitro assessments of photocytotoxicity will be discussed in detail.

Figure 1
(Invited) C60-Based Switchable Fluorescent Probes
Authors: Ma Yue , Persi Lorenzo , Yan Shen , Baumgartner Martin , Yamakoshi Yoko
Published: August 2024

Photodynamic therapy (PDT), an emerging non-invasive tumor treatment, requires suitable photosensitizer (PS) molecules that generate reactive oxygen species (ROSs) efficiently under long wavelength of light with deep tissue penetration, ideally activated in the diseased tissue. C60 is known as an excellent acceptor molecule in both electron- and energy-transfer reactions and exhibits biocompatibility and efficient ROS generation, rendering it a promising candidate as a PS for PDT.

In this study, we developed a C60-based dual-functional molecular probe containing a water-soluble C60-peptide and a donor fluorophore connected with a ligand peptide specific for matrix metalloproteinases (MMP) (Figure 1). We expect that such a molecular probe can be used in both diagnostic imaging and concurrent treatment. The probe revealed increased fluorescence signal and 1O2 generation in the presence of MMP2/9 enzymes that are known to be overexpressed in tumor cells. Furthermore, in vitro cellular tests demonstrated the probe's abilities in imaging MMP activity and photocytotoxicity on MMP-expressing tumor cells.

Figure 1
(Invited) Reactivity on Endohedral Metallofullerenes
Authors: Abella Guzman Laura , Rodriguez-Fortea Antonio , Poblet Josep M.
Published: August 2024

Endohedral metallofullerenes (EMFs) are fullerene molecules with unique host-guest structures that allow chemists to manipulate encapsulated metal ions with the arsenal of organic chemistry, for potential applications including spin-quantum computing, single-molecule magnets, dynamic nuclear polarization, artificial photosynthesis, magnetic resonance imaging contrast agents, and therapeutic agents. To unleash the power to do so, the development of new reactions for EMFs has been an ongoing task.

A key step to improve the solubility of EMFs as well as to obtain new materials for multiple applications is via exohedral functionalization. In medicine, for instance, water-soluble gadofullerenols are used as powerful contrast agents.1 Besides, the external groups might impart complementary features to EMFs that tune their physical properties for use as acceptors in polymer solar cells or as donor-acceptor dyad conjugates.2 Among the most used methods to obtain EMF monoadducts are cycloaddition reactions and radical additions, including the Diels-Alder cycloaddition, Bingel-Hirsch cyclopropanation, Prato 1,3-dipolar addition, carbene addition, etc. In these reactions, fullerenes typically play a similar electron-accepting role, thus their reactivity and regioselectivity are highly consistent. However, the reactivity of EMFs is far more complicated than of empty fullerenes due to the relatively low molecular symmetry and the influence of the encapsulated species. To understand the role of metal-cage interactions on the reactivity of EMFs is desirable for tuning their chemical reactivity.

Here, we report the functionalization of actinide endofullerenes, in particular, the mono-EMFs U@C
s(4)-C82 and U@C
2v(9)-C82, which their chemical reactivities were investigated through the Bingel-Hirsch (nucleophilic addition) and carbene addition (electrophilic addition) reactions. Interestingly, only for U@C
2v(9)-C82, the Bingel-Hirsch reaction leads to mono-adduct and multi-adduct compounds. Another subgroup of EMF that we study its reactivity here is the nitride clusterfullerenes, especially the Lu3N@Ih-C80, with high stability and high production yields, that results its chemical modification to be challenging. In this case, the reaction studied is the inverse-electron demand Diels-Alder (IEDDA) reaction and it will be compared to the corresponding reactivity on C60 fullerene. We show that Lu3N@Ih-C80presents higher reactivity than for C60, as well as, different features.

1Bolskar, R. D.; Benedetto, A. F.; Wilson, L. J.; Alford, J. M. et al. J. Am. Chem. Soc. 2003, 125, 5471-5478.

2Ross, R. B.; Cardona, C. M.; Guldi, D. M. et al. Nature Mater. 2009, 8, 208-212.

Figure 1
Ultrafast Charge Transfer Cascade in a Mixed-Dimensionality Nanoscale Trilayer
Authors: Hermosilla Palacios Martha Alejandra , Blackburn Jeff , Myers Alexis , Li Zhaodong , Gish Melissa , Earley Justin , Johnson Justin
Published: August 2024

Innovation in optoelectronic semiconductor devices is driven by a fundamental understanding of how to move charges and/or excitons (electron-hole pairs) in specified directions for doing useful work, e.g. for making fuels or electricity. The diverse and tunable electronic and optical properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs) and one-dimensional (1D) semiconducting single-walled carbon nanotubes (s-SWCNTs) make them good quantum confined model systems for fundamental studies on charge and exciton transfer across heterointerfaces. In nature, the photosynthetic apparatus achieves long-lived charge separation through a charge transfer cascade that consists of a series of thermodynamically downhill charge transfer reactions. Inspired by photosynthesis we create a unique mixed-dimensionality 2D/1D/2D MoS2/SWCNT/WSe2 hetero-trilayer. Photoexcitation of this trilayer heterostructure allows us to overcome both intralayer and interlayer exciton binding energies, resulting in coulombically unbound charges with microsecond recombination lifetimes. In contrast to previously demonstrated 2D/2D/2D trilayers based solely on monolayer TMDC layers, the very large charge mobilities and extended electron network of the 1D semiconducting SWCNT layer helps charges delocalize and diffuse away from the interface at which each type of charge is generated. Interestingly, the hetero-trilayer also appears to enable efficient hole transfer from SWCNTs to WSe2, which is not observed in the identically prepared WSe2/SWCNT heterobilayer, suggesting that new dynamic pathways may be opened by increasing the complexity of nanoscale heterostructures. Our work suggests "mixed-dimensionality" TMDC/SWCNT based hetero-trilayers as both interesting model systems for mechanistic studies of carrier dynamics at nanoscale heterointerfaces, and for potential applications in advanced optoelectronic systems.
Invited: Mimicking Biological Synapse Activity with LDH-Based Memristor
Authors: Ignatova Tetyana
Published: August 2024

Memristors, mimicking biological synapse response, are believed to have a great potential for use as an adaptive memory unit in future neuromorphic computing systems. Here we report on fabrication of two-dimensional memristor comprised of layered double hydroxide (LDH) material, covered with graphene layer, serving as a terminal for connecting to electrodes. We demonstrated nonvolatile resistive switching of LDH memristor. Device performance is studied upon replacing graphene semimetal with alternative 2D materials. Comprehensive characterization of the memristor materials was performed with correlated Raman, Electron, and Scanning Probe Microscopy methods.

ACKNOWLEDGMENT

This work was supported by the US Department of Defense (Contract #W911QY2220006), 2DCC-MIP NSF cooperative agreement DMR-2039351. Work was performed at JSNN, a member of the Southeastern Nanotechnology Infrastructure Corridor (SENIC) and National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the NSF (ECCS-1542174)
(Nanocarbons Division Poster Award, 3rd Place) Hybrid Supercapacitance and Stability of Fe-Based Metal-Organic Frameworks/Graphene Oxide Nanoribbons Composite Allover the pH Range
Authors: Heiba Asmaa R. , Abdelsalam Mohamed O , Yoon Taeho , El Sawy Ehab N
Published: August 2024

Adopting renewable energy sources is growing fast, and hence it should be accompanied by tremendous efforts to develop energy storage technologies that can mitigate the intermittent nature of these sources. Supercapacitors (SCs) are considered among the most promising technologies for that purpose due to their high durability, power density, and charging/discharging competency. SCs have two types according to their electrochemical charge storage mechanism: pseudocapacitance (PCs) or battery-like behavior and electrochemical double-layer capacitors (EDLCs). The development of next-generation supercapacitors requires a holistic approach that integrates both mechanisms. Because of their huge surface area, porous structure, and abundance of active redox sites, metal-organic frameworks (MOFs) have exceptional potential in energy storage devices. However, due to the MOFs’ low conductivity and stability, they are in need to be mixed with highly conductive and stable materials such as carbon-based ones.

In this work, Fe-based MOFs were selected to be responsible for mainly the battery-like contribution to the overall supercapacitance due to the presence of the redox-active sites. Even though little attention has been given to the Fe-based MOFs they showed a promising performance in several solutions, with low stability.1,2 To enhance the Fe-MOFs stability and conductivity and add an EDLC component to the overall capacitance behavior graphene oxide nanoribbon (GONRs) was used. The GONRs' exceptional properties such as ultrathin two-dimensional structures, superior mechanical behavior, strong chemical stability, and high electrical conductivity make them promising materials for supercapacitor applications.

In this study, Fe-MOFs were synthesized using a hydrothermal method,3 and GONRs were prepared using an oxidative unzipping method.4 A composite of Fe-MOFs/GONRs was prepared by physical mixing. The physical and chemical properties of the synthesized Fe-MOFs, GONRs, and Fe-MOFs/GONRs were characterized using XRD, SEM, TEM, FT-IR, Raman spectroscopy, and XPS. Since the electrolyte properties have a substantial impact on the supercapacitive behavior and stability of the electrode materials, the specific capacitance of the prepared composites was measured in 1M H2SO4, 1M KOH, 1M K2SO4, and 1M KCl utilizing different evaluation systems (three and two-electrode systems). The Fe-MOFs/GONRs composite showed a significant synergistic effect in comparison to its pure components. Further discussion will be given regarding the pH and ion size/type effect on the supercapacitive performance and stability.

References:

B. Ramasubramanian et al., Surf. Interfaces, 34, 102397 (2022).

J. Xie, R. Ma, H. Fang, H. Shi, and D. Liu, Cryst. Growth Des., 22, 2997–3006 (2022).

J. Joseph et al., Chemosphere, 284, 131171 (2021).

D. V. Kosynkin et al., Nature, 458, 872–876 (2009).
A Rechargeable Solid-State Sodium-Oxygen Battery with Enhanced Energy Efficiency and Cycle Life
Authors: mosen Harzandi Ahmad , Azaribeni Adel , Asadi Mohammad
Published: August 2024

Sodium-oxygen (Na-O2) batteries offer a promising path for the advancement of high-energy-density inexpensive storage systems to replace current state of the art Li-based batteries owing to the natural abundance and low-cost Na metal. Despite numerous studies to improve the performance of liquid-based electrolyte Na-O2 batteries, this technology suffers from poor cycle life, electrolyte stability issues, and limited choice of cell design as well as growing safety concerns associated with liquid electrolytes. Recently, solid electrolytes received a great attention to substitute traditional liquid electrolytes used in Na-O2 batteries, due to their ability of improving safety and energy density. However, low ionic conductivity and high impedance in contact with the anode and cathode remain as major challenges for the development suitable solid-state electrolyte for Na-O2 batteries.

In addressing these challenges, we recently have established a solid-state Na-O2 battery cell that comprises a highly conductive composite polymer-ceramic solid electrolyte with a conductivity of 0.7 mS/cm. This solid electrolyte works in synergy with vanadium phosphide (VP) nanoparticles, serving as oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts at the cathode and Na metal anode for more than 500 reversible charge-discharge cycles at a capacity of 1000 mAh/g, achieving a low polarization gap of approximately 20 mV in the first cycle. Various electrochemical and physicochemical characterization techniques, such as Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), differential electrochemical mass spectrometry (DEMS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), were employed to gain insight into the cell chemistry and solid-state electrolyte role in the formation and decomposition of sodium oxides components such as superoxide (NaO2), peroxide (Na2O2). The findings of this study underscore the significance of proper cell component design and possible mechanisms in solid-state Na-O2 battery technologies. This research represents a promising avenue in advancing energy conversion and storage systems, showcasing the potential of solid-state batteries with enhanced safety and performance characteristics.
Electrochemical Lithium Intercalation & Exfoliation in 2D TMDs and Its in-Situ Studies
Authors: Zeng Zhiyuan
Published: August 2024

We developed a lithium ion battery intercalation & exfoliation method with detailed experimental procedures for the mass production of 11 two dimensional TMDs and inorganic nanosheets, such as MoS2, WS2, TiS2, TaS2, ZrS2, graphene, h-BN, NbSe2, WSe2, Sb2Se3 and Bi2Te3, among them 3 TMDs achieved mono- or double layer yield > 90%. This method involves the electrochemical intercalation of lithium ions into layered inorganic materials and a mild sonication process. The Li insertion can be monitored and finely controlled in the battery testing system, so that the galvanostatic discharge process is stopped at a proper Li content to avoid decomposition of the intercalated compounds. The intercalation strategy can also be used to tune 2D TMDs’ physical and chemical properties for various applications. For example, we developed a one-step covalent functionalization method on MoS2 nanosheets for membrane fabrication, which exhibited excellent water desalination performance. For lithium intercalation mechanism, the state-of-the-art In-Situ Liquid Phase TEM is an ideal technique for identifying the phase changes during intercalation process. With self-designed electrochemical liquid cell utilized, we can directly vapture the dynamic electrochemical lithiation and delithiation of electrode in a commercial LiPF6/EC/DEC electrolyte, such as LiF nanocrystal formation, lithium metal dendritic growth, electrolyte decomposition, and solid-electrolyte interface (SEI) formation. Combining with other in-situ techniques, such as in-situ XAS, XRD and Raman, etc, the underlying lithium intercalation mechanism in TMDs were further investigated, which render us a comprehensive understanding of the intrinsic correlation between the intercalation process and TMDs.

References:

[1] R. Yang, L. Mei, et al., H. S. Shin*, D. Voiry*, Z.Y. Zeng*, Nat. Protoc., 2022, 17, 358-377.

[2] R. Yang, et al., H. S. Shin, D. Voiry, Q. Lu, J. Li*, Z. Y. Zeng*, Nat. Synth., 2023, 2, 101-118.

[2] R. Yang, L. Mei, Y. Fan, Q. Zhang, H. G. Liao, J. Yang, J. Li*, Z. Y. Zeng*, Nat. Protoc., 2023, 18, 555-578.

[3] Q. Zhang, J. Ma, L. Mei, J. Liu, Z. Li*, J. Li*, Z. Y. Zeng*, Matter, 2022, 5, 1235-1250.

[4] H. Peng, R. Wang*, L. Mei, et al., Z. Qian*, A. B. Farimani, D. Voiry*, Z. Y. Zeng*, Matter, 2023, 6, 59-96.

[5] L. Mei, et al., C. Y. Tang, D. Voiry, H. Wang*, A. B. Farimani*, Z. Y. Zeng*, Adv. Mater., 2022, 34, 2201416.

[6] R. Yang, Y. Fan, R. Ye, Y. Tang, X. Cao*, Z. Yin*, Z. Y. Zeng*, Adv. Mater. 2021, 33, 2004862.

[7] R. Yang, Y. Fan, et al., Q. Lu, Q. Wang,* J. C. Yu,* Z. Y. Zeng*, Angew. Chem. Int. Ed., 2023, e202218016.

[8] B. Tian, D. Ho*, J. Qin, et al., D. Voiry, Q. Wang*, Z. Y. Zeng*, Prog. Mater. Sci., 2023, 133, 101056.

[9] R. Yang, et al., Z. Y. Zeng*, Photocatalysis with atomically thin sheets, Chem. Soc. Rev., 2023, 52, 7687.
(Invited) Insights into the Electrocatalytic Behavior of Mxenes
Authors: Yoo Ray , Johnson Denis , Djire Abdoulaye
Published: August 2024

The continued rise in global energy consumption, along with the associated environmental hazards, pose a significant risk to our society’s infrastructure unless the main source is changed. Electrocatalysis involving hydrogen evolution reaction (HER), nitrogen reduction reaction (NRR), and oxygen reduction reaction (ORR), provide a pathway for energy storage and conversion due to their enhanced environmental friendliness and efficient energy input compared to their thermocatalytic counterparts. Currently, the state-of-the-art electrocatalysts suffer from scarcity and high cost. MXenes, a novel family of two-dimensional (2D) transition metal carbide and nitride materials, show potential as cost-efficient and highly abundant electrocatalysts with limited knowledge on their electrocatalytic mechanisms. This is especially true when considering the often-overlooked nitride family of MXenes. Herein, we investigate the electrocatalytic performance of a Ti2N nitride MXene under different electrocatalytic conditions. The effect of surface phenomena is investigated through manipulation of the surface passivation layer, as evidenced by Raman and Fourier-transform infrared (FTIR) spectroscopies, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Successful decoupling of the bulk and surface phenomena is achieved through Raman laser power attenuation. Under acidic medium, the surface reactivity towards HER is poor but the bulk reactivity for NRR is favored, making it an optimal NRR catalyst. Under alkaline medium, the surface reactivity of the pristine Ti2N MXene for ORR is high, but also leads to surface passivation and thus hinders the electrocatalytic activity. Overall, these results provide fundamental insights into future optimization strategies of the Ti2N nitride MXene, along with other MXene electrocatalysts, towards electrocatalytic applications.
(Invited) Activating Nitrogen for Electrochemical Ammonia Synthesis: Modeling the Effects of Electrified Interfaces on π-Backbonding Molecules
Authors: Aubry Taylor , Clary Jacob M , Miller-Link Elisa , Vigil-Fowler Derek , van de Lagemaat Jao
Published: August 2024

Electrocatalysts are expected to play a pivotal role in shaping our future sustainable energy landscape by enabling storage of renewable energy and its conversion into globally important chemicals. Computational simulations yield mechanistic insights that have supported catalyst discovery and optimization. However, the complexity of electrocatalyst interfaces has necessitated the development of quantum chemical methods that can accurately model these effects at reasonable computational cost.

In this work, we employ grand canonical density functional theory (GC-DFT) to capture the nuanced effects of applied potential on a solvated catalyst interface, specifically focusing on the nitrogen reduction reaction (NRR) at sulfur vacancies in 1T'-phase MoS2. In the canonical method, the widely used the computational hydrogen electrode (CHE) predicts that adsorbed N2 structure properties are potential independent. In contrast, GC-DFT calculations reveal that reductive potentials activate N2 towards electroreduction by modulating backbonding strength, lengthening the N–N triple bond, and reducing its bond order. Similar trends are identified for CO, a classic backbonding ligand, suggesting broader relevance of this mechanism to diverse electrochemistries involving backbonded adsorbates. Furthermore, reductive potentials are required to make the subsequent N2 hydrogenation steps favorable, but concurrently destabilize both N2 and hydrogen adsorption.

Our findings demonstrate that GC-DFT facilitates the comprehensive modeling of these phenomena, underscoring their collective implications in predicting electrocatalyst selectivity for the nitrogen reduction reaction and potentially other reactions. This research contributes valuable insights into the design and optimization of electrocatalysts for sustainable energy conversion.

Figure 1