Intercalation Site Research Articles

Cyto-Genotoxic Assessment of Sulfoxaflor in Allium cepa Root Cells and DNA Docking Studies.

Sulfoxaflor (SFX) is an insecticide that is commonly used for the control of sap-feeding insects. Since SFX is extensively applied globally, it has been implicated in the substantial induction of environmental toxicity. Therefore, in this study, Allium cepa roots have been employed to elucidate the potential cytogenotoxic effects of SFX in non-target cells by examination of mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. Physiological effects of SFX were evaluated by A. cepa root growth inhibition assay, while cytogenotoxic effects were assessed by A. cepa ana-telophase and comet assay. Moreover, DNA binding affinity and binding mode of SFX were examined using molecular docking simulations to shed light on the genotoxic mechanism of action. The half maximal effective concentration (EC50) on the growth of A. cepa cells calculated for SFX was found as 500 mg/L. Moreover, dose- and time-dependent decrease in MI, increase in CAs (disturbed ana-telophase, chromosomal laggards, stickiness, and anaphase chromosome bridge) and DNA damage were observed by the exposure of A. cepa root tips to SFX after 24-, 48-, 72-, and 96-h treatment periods. A 6-bp double-stranded DNA structure containing two intercalation sites (PDB ID: 1Z3F) was used for docking studies. According to DNA docking results, SFX exhibited an energetically more favorable binding affinity with DNA (ΔG = -5.05 kcal/mol) compared with the experimental mutagen methyl methanesulfonate (MMS) (ΔG = -2.94 kcal/mol), and preferentially snugly fits into the minor groove of DNA possessing an intercalation gap, thus, providing valuable mechanistic data into the formation of chromosome aberrations and DNA fragmentation induced by this pesticide in A. cepa.

Mechanically Induced Surface Defect Engineering in Expanded Graphite to Boost the Low-Voltage Intercalation Kinetics for Advanced Potassium-Ion Batteries

Enhancing carbon materials' low-potential K+ intercalation capacity is an essential topic in potassium-ion batteries (PIBs). Nevertheless, conventional methods effectively improve performance by increasing the surface area and active sites, but always at the expense of initial coulombic efficiency (ICE). Herein, an efficient and convenient strategy is proposed to construct self-doped defective carbon nanosheets (SDCS) using the mechanical ball-milling technique. This in situ defect engineering increases K+ intercalation sites and shortens the ionic pathway, enhancing the ionic intercalation kinetics, specific capacity, and ICE. As expected, the SDCS-24 electrode delivers an ultra-high low-potential capacity of 314.3 mAh g-1 below 0.5 V, high ICE of 76.1%, and long-term cycle stability (300.1 mAh g-1 after 1800 cycles at 1 C). The K+ storage mechanism is determined by ex situ XRD and in situ Raman. The full-cell with 3,4,9,10-Perylenetetracarboxylic dianhydride cathode and SDCS-24 anode further confirms its promising application. This work presents a strategy for designing self-doped defective carbons in situ and provides insights into the potassium storage mechanism at low potential.

Unraveling the conversion mechanism toward spinel sulfides as cathode materials for Mg-ion batteries.

Rechargeable Mg batteries are promising candidates for achieving considerable high-energy-density. Enhancing the energy density can be achieved by integrating metallic Mg anodes with conversion-type cathode materials, which are characterized by multi-electron transfer process and elevated specific capacities in contrast to intercalation-type materials. Despite these advantages, the conversion-type cathodes still have some challenges of substantial volume expansion, sluggish diffusion kinetics and intricate mesophase evolution during repeated electrochemical reactions. Herein, first-principles calculations were performed to probe into the electronic properties, Mg2+ dynamical properties, Bader charge and electrochemical mechanism of spinel-type sulfides (M3S4, M = Co and Ni). The band gap values of Co3S4 and Ni3S4 are 0.28 and 0 eV, respectively, showing their superior electrical conductivity. The preferential order of Mg intercalation sites is 16c > 48f > 8b. Computational predictions of the formation energy and discharge voltage indicate that spinel Ni3S4 can exhibit a relatively high specific discharge capacity of 220.8 mA h g-1 and an average voltage of ∼1.6 V vs. Mg2+/Mg with an energy density of 353.3 W h kg-1 at a Mg intercalation concentration of x2+Mg = 1.25, surpassing those of Co3S4 and Mo6S8. According to the principle of the lowest barrier, the diffusion pathway "oct → tet → oct" of spinel sulfides Co3S4 and Ni3S4 has low Mg migration barrier values of 1.10 and 0.67 eV, respectively. The Bader charge and AIMD results revealed that the spinel M3S4 (M = Co and Ni) underwent conversion reactions to the rock-salt phase especially at deep discharge. These insights significantly advance the rational design of spinel sulfides with a conversion reaction mechanism, providing great potential for the development of Mg batteries with high energy density.

Chlorinated graphite as positive electrode for aluminium-ion batteries with 1-ethyl-3-methylimidazolium chloride/aluminium chloride electrolyte

The article defines the dependence type of the cathode polarization of an aluminum-ion battery based on chlorinated graphite of the initial EC-02 type in a low-temperature melt of aluminum chloride with 1-ethyl-3-methylimidazole chloride on the geometric characteristics of the electrode and the current density. It is determined that for the chlorinated graphite material the polarization values are slightly reduced compared to the initial non-chlorinated graphite of the same brand in a similar melt and are 25–50 mV at 1 mA/cm2. The dependence of polarization on the current density does not have a break between the values of 1 and 1.2 mA/cm2, observed for initial graphite, which characterizes the maximum rate of the current-generating reaction, which means an increase in the rate of the main process on the chlorinated graphite. Using a reference experiment on a glassy carbon electrode, the surficial density of chloroaluminate complexes intercalation sites was estimated as about 15%. Accordingly, the maximum degree of intercalation for such materials is 6. Since graphite chlorination does not lead to distortions geometric parameters of its interlayer gaps, the sorption density of chloroaluminate ions is found to increase after chlorination; in the case of non-chlorinated graphite, the degree of intercalation varies with current density from 9 to 18.

Rigid-Flexible Coupling Realized by Synergistic Engineering of the Graphitic-Amorphous Architecture for Durable and Fast Potassium Storage.

Graphite anodes hold great potential for potassium-ion batteries (PIBs), yet their practical application is hindered by poor cycle performance caused by substantial interlayer expansion. Herein, a partial graphitic carbon (PGC) is elaborately engineered via the catalytic effect of ferric citrate using pitch as a carbon precursor. Systematically varying the catalyst content enables an optimal PGC design integrating a highly graphitized phase providing abundant active sites for K-ion intercalation, balanced with an amorphous carbon region that accommodates volume expansion and facilitates ion diffusion. The optimized PGC12 electrode exhibits a high reversible capacity of 281.9mAhg-1, characterized by a prolonged low-potential plateau region, and excellent cycle stability with a capacity retention of 94.8% after 300 cycles. It also realizes an impressive rate capability with a retained capacity of 222.2mAhg-1 at 1C. Moreover, the assembled K-ion full-cell delivers an exceptional energy density of 148.2Whkg-1. In-situ XRD and DFT simulations further verify the distinct phase transition mechanisms and reaction dynamics across different carbon configurations. This work elucidates the impact of carbon configurations on K-storage performance and proposes a structural model for efficient K-ion storage, which is instrumental in the rational design and advancement of carbon anodes in PIBs.

Investigation of Sodium Leaching into Electrolytes during Electrochemical Testing

Many mechanisms and degradation pathways have been identified in the literature that result in leaching of transition metals from the cathode, resulting in loss of capacity during cycle life testing due to fewer sites for lithium intercalation into the cathode during discharge1. But electrode formulations contain more components than just active material- there are also binders, conductive carbon, other additives, and coatings. The extent to which these other components can break down and cause electrode degradation and any subsequent effects on cell performance is not well known. This poster explores the chemical and electrochemical influences on extraction of materials from electrodes, such as sodium, that may be harmful to battery performance. Post mortem analyses of electrolytes after electrochemical testing in multilayer pouch cells have found sodium content in the range of 200-300 ppm, well above typical specifications for battery-grade products (1-10 ppm). The most probable source of sodium in the battery is sodium carboxymethyl cellulose (CMC), often used in graphite anodes as a rheology modifier during production. In this study, the leachability of sodium from CMC in various extraction solutions was investigated through model systems. Model system experiments have shown that while the sodium in CMC was insoluble in organic solvents and electrolyte, sodium can be extracted by contact between salt-containing electrolytes and CMC-containing anodes. The amount of sodium recovered in the model system closely corresponds with the amount that was recovered from cells after electrochemical operation. Other anode and cell components were also analyzed as potential sources of sodium, and the prospect of each of these as a source of sodium was explored. Finally, the effect of different levels of sodium content on cell performance was rigorously tested by doping lithium-ion electrolytes with NaPF6 and testing these electrolytes in pouch cells. Overall, we show that sodium can be a major contaminant extracted into the electrolyte during cycling in pouch cells, and investigate the impact of sodium content on critical performance metrics.1 Ochida, M.; Domi, Y.; Doi, T.; Tsubouchi, S.; Nakagawa, H.; Yamanaka, T.; Abe, T.; Ogumi, Z. Influence of Manganese Dissolution on the Degradation of Surface Films on Edge Plane Graphite Negative-Electrodes in Lithium-Ion Batteries. Journal of the Electrochemical Society 2012, 159(7), A961-A966.

Capacity Fade Analysis of Sodium-Ion Batteries Considering Calendar Ageing in Electric Vehicles

Sodium-ion batteries are emerging as a prominent candidate among next-generation energy-storing devices. These batteries are characterised by their similar architecture to lithium-ion batteries. The significant advantage of sodium-ion batteries (SIBs) is their abundant raw material and “drop-in” technology to the existing lithium-ion battery manufacturing units.1 SIBs are anticipated to have their utility in microgrid systems and low-speed electric vehicles.2 The primary concern with these batteries is capacity fade during charge-discharge cycling, limiting their life. Several degradation mechanisms occur in SIBs, such as solid electrolyte interface (SEI) layer formation and sodium plating.3 The SEI layer is formed due to the continuous electrolyte decomposition, leading to its cumulative growth, as shown in Figure 1(a).4 Sodium plating is another degradation mechanism caused due to the insufficient intercalation sites leading to sodium aggregates on the anode pores.5 The modelling and simulation of these degradation mechanisms using physics-based models will give insights into the battery’s internal dynamics that affect their performance. This work focuses on the analysis of sodium-ion battery degradation for electric vehicles, considering calendar ageing, using the PyBaMM software package.6 A pseudo-2-dimensional electrochemical model developed for SIB is coupled with the different degradation models to analyse the internal dynamics of the battery.7 The SEI layer growth is captured using the ethylene carbonate reaction-limited model, which assumes that the diffusion rate of electrolyte solvent ethylene carbonate is a prominent cause for the SEI layer formation.8 The charge transfer kinetics of sodium plating and stripping are expressed in the form of the Butler-Volmer equation.7 The sodium-ion chemistry used in this study uses a hard carbon anode, sodium vanadium fluorophosphate cathode and 1M NaPF6 in EC0.5:PC0.5 (w/w) solvent as an electrolyte.9 This study uses the Urban Dynamometer Driving Schedule (UDDS) drive cycle for low-duty vehicles for city driving conditions.10 The electrochemical model, degradation models, and UDDS drive cycle are used to assess the battery performance for electric vehicle applications for one year. The simulation replicates real-time commuting between home and office, followed by the charging phase.11 The quantities, such as total capacity loss, SEI layer thickness and sodium inventory loss, were estimated and will be discussed as shown in Figure 1(b). The effect on surface kinetics and overall cycle life due to the electrolyte diffusive flux will be analysed. Strategies for the improvement of battery lifespan will be discussed. References K. Chayambuka, G. Mulder, D. L. Danilov, and P. H. L. Notten, Adv. Energy Mater., 10, 1–11 (2020).S. F. Schneider, C. Bauer, P. Novák, and E. J. Berg, Sustain. Energy Fuels, 3, 3061–3070 (2019) http://xlink.rsc.org/?DOI=C9SE00427K.W. Luo et al., Nano Lett., 17, 3792–3797 (2017).B. Philippe, M. Valvo, F. Lindgren, H. Rensmo, and K. Edström, Chem. Mater., 26, 5028–5041 (2014).J. Hedman, R. Mogensen, R. Younesi, and F. Björefors, ACS Appl. Energy Mater., 5, 6219–6227 (2022) https://pubs.acs.org/doi/10.1021/acsaem.2c00595.V. Sulzer, S. G. Marquis, R. Timms, M. Robinson, and S. J. Chapman, J. Open Res. Softw., 9, 14 (2021) https://openresearchsoftware.metajnl.com/article/10.5334/jors.309/.S. E. J. O’Kane et al., Phys. Chem. Chem. Phys., 24, 7909–7922 (2022).X. G. Yang, Y. Leng, G. Zhang, S. Ge, and C. Y. Wang, J. Power Sources, 360, 28–40 (2017) http://dx.doi.org/10.1016/j.jpowsour.2017.05.110.K. Chayambuka, M. Jiang, G. Mulder, D. L. Danilov, and P. H. L. Notten, Electrochim. Acta, 404, 139726 (2022) https://doi.org/10.1016/j.electacta.2021.139726.United States Environmental Protection Agency, https://www.epa.gov/vehicle-and-fuel-emissions-testing/dynamometer-drive-schedules.D.-I. Stroe, M. Swierczynski, S. K. Kaer, E. M. Laserna, and E. S. Zabala, in 2017 IEEE Energy Conversion Congress and Exposition (ECCE),, vol. 2017-Janua, p. 5631–5637, IEEE (2017) http://ieeexplore.ieee.org/document/8096937/. Figure 1

Modeling Capacity Losses Due to Irreversible Volume Change in Lithium-Ion Batteries

During operation of lithium-ion batteries, cells experience volume change due to mechanical and electrochemical phenomena. This volume change can be described in two main modes: reversible and irreversible. Irreversible volume change permanently affects cell performance, often lowering the maximum capacity of cells over time making them less effective in storing energy. Irreversible volume change can come from a few different sources such as gasification of the electrolyte, dendritic growth or plating of lithium metal, and SEI growth on the active material. These phenomena reduce the effectiveness of battery cells by removing working ions from the electrolyte and blocking intercalation sites of the active material.Quantifying this behavior experimentally can be drawn-out, as cells must be properly cycled thousands of times as they would be in consumer applications. In order to speed up this process and test many different cell designs, simulations that can quantify the irreversible volume change and resultant capacitive losses should be developed. The 3D microstructure-based modeling method developed by Lopata offers a strong framework for development of these simulations. Through a combination of experimental cycling data and electrochemical simulations, volume change from irreversible sources can be accurately represented at a microscale level and extrapolated into cell level response.In this work, discrete element simulations (DEM) have been developed to quantify local irreversible volume change. These DEM simulations utilize data from electrochemical simulations with an equivalent microstructure, which have been informed from experimental measurements at a cell level. This can be coupled with reversible volume expansions in the DEM framework to give a full picture of volume change at the electrode/electrolyte microscale. The irreversible volume change predicted by the DEM simulations is used to estimate capacitive losses in the cell overtime.References T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, J. Electrochem. Soc., 170, 113502 (2023).U. Janakiraman, T. R. Garrick, and M. E. Fortier, J. Electrochem. Soc., 167, 160552 (2020).T. R. Garrick, J. Gao, X. Yang, and B. J. Koch, J. Electrochem. Soc., 168, 010530 (2021).T. R. Garrick et al., J. Electrochem. Soc., 170, 060548 (2023).A. Paul et al., J. Electrochem. Soc., 171, 023501 (2024).M. Song, Y. Hu, S.-Y. Choe, and T. R. Garrick, J. Electrochem. Soc., 167, 120503 (2020).S. T. Dix, J. S. Lowe, M. R. Avei, and T. R. Garrick, J. Electrochem. Soc., 170, 083503 (2023).T. F. Fuller, M. Doyle, and J. Newman, Journal of the electrochemical society, 141, 1 (1994).M. Doyle, T. F. Fuller, and J. Newman, Journal of the Electrochemical society, 140, 1526 (1993).J. S. Lopata et al., J. Electrochem. Soc., 170, 020530 (2023).S. Pannala, H. Movahedi, T. R. Garrick, A. G. Stefanopoulou, and J. B. Siegel, J. Electrochem. Soc., 171, 010532.T. R. Garrick, Y. Miao, E. Macciomei, M. Fernandez, and J. W. Weidner, J. Electrochem. Soc., 170, 100513 (2023)

Study of Electrochemical Characteristics of Differently Produced Nickel-Rich Cathodes

Lithium-ion batteries stand as the forefront technology in energy storage. Significant endeavors have been dedicated to enhancing the energy density of lithium-ion batteries, primarily by incorporating high-capacity nickel-rich cathode active materials like NCM831205 or even higher nickel contents [1]. Nevertheless, an elevated nickel content result in reduced structural and thermal stabilities, increased reactivity with the electrolyte, and heightened vulnerability to environmental influences due to the formation of surface films [2–4]. To mitigate these effects, specialized processing conditions are necessary, such as treatment exclusively in a dry atmosphere or the incorporation of specific electrolyte additives [5,6]. However, the processing method and its diverse parameters play a critical role in battery performance. Particularly, the mixing process of the slurry holds pivotal importance in determining electrode quality, as it is during this phase that the intricate structures and internal networks of the electrode are established. These structures significantly influence the diffusion of lithium ions, thereby impacting cell performance profoundly. The mixing conditions, along with the selection of the mixing device and geometry, exert a substantial impact on material dispersion, aimed at reducing the size of carbon black (CB) agglomerates to smaller aggregates.For optimal quality in electrode production, an efficient dispersion step is crucial, often performed using a dissolver in a dry room environment to mitigate any impact from residual moisture and potential chemical reactions with the electrolyte. The efficacy of the dispersion process hinges significantly on the selected disk diameter and height concerning the liquid level. Since both geometric parameters influence the slurry's flow properties during dispersion, discerning their exact impact on the formation of the conductive network poses a challenge. Hence, this study employs variations in these parameters to produce diverse electrode structures. The dispersion index (DICB), as introduced by Weber et al., serves as a quantitative metric to assess the progress of dispersion [7].The electrodes produced undergo impedance measurements to assess contact and ionic resistances. For this evaluation, the model proposed by Landesfeind et al. and its associated circuitry are employed [8]. Moreover, 4-point measurements are conducted to ascertain the volume resistance or electrical conductivity within the electrode. Subsequently, the electrodes are subjected to measurements in a 3-electrode setup within the full cell configuration, with a capacity of 4 mAh, to analyze their performance and fast-charging capability. Moreover, the utilization of differential capacity plots enables the derivation of direct correlations between CB decomposition, the resultant structure, and the kinetic limitations induced by these structures. These assessments reveal three distinct ranges of electrode properties within the DICB. Notably, these ranges exhibit direct correlations with contact, ionic and volume resistances, as well as cell performance.The observed ranges indicate that insufficient CB decomposition results in low ionic resistance but also leads to elevated contact resistance. Additionally, the presence of excess binder, acting as inert material, contributes to kinetic limitations. Conversely, excessive DICB’s lead to a notable surge in ionic resistance and to the occupation of intercalation sites on the active material by unbound CB particles, thereby restricting the number of phase transitions of nickel and subsequently diminishing the capacity. For this reason, a defined range can be established within which the electrochemical properties of the electrode must lie in order to achieve maximum capacity and optimal fast-charging capability.

Fabrication of Two-Dimensional Heterostructure Electrodes for Intercalation Batteries Via Cation-Driven Assembly

The cation-driven assembly technique was developed and employed to fabricate two-dimensional (2D) heterostructures of lithium preintercalated bilayered vanadium oxide (δ-LixV2O5·nH2O or LVO) and graphene oxide (GO) nanoflakes. These heterostructures were formed using concentrated lithium chloride solution and annealed under vacuum at 200ºC. The presence of Li+ ions from LiCl enhanced the formation of oxide/carbon heterointerfaces, improving structural and electrochemical stability. Annealing at 200ºC allowed to remove interlayer water excess and partially reduce GO, thus improving electron transport through reduced GO (rGO) nanoflakes. By varying the initial GO concentration, the carbon content in the heterostructures could be adjusted, affecting the electrochemical performance. Scanning transmission electron microscopy (STEM) imaging combined with electron energy-loss spectroscopy (EELS) clearly revealed the formation of LVO/rGO heterointerface with rGO nanoflakes with thicknesses down to the nanometer scale embedded between the nanometer-thick layers of LVO.Electrochemical cycling of the Li+ cation-assembled LVO/rGO heterostructures in Li-ion cells demonstrated enhanced cycling stability and rate performance with increasing rGO content, despite a slight decrease in charge storage capacity. The improved electrochemical stability was attributed to what we have termed the encapsulation effect, which involves the encasing of LVO nanoflakes between the rGO nanoflakes, leading to the suppressed dissolution of LVO in the electrolyte and mitigating the structural distortion of LVO known to be induced by repeated intercalation/deintercalation reactions during electrochemical cycling. Compared to the electrodes prepared by physical mixing of LVO and rGO nanoflakes, the cation assembled LVO/rGO heterostructures showed superior electrochemical stability, highlighting the stabilizing effect of the 2D heterointerface.The versatility of the cation-driven assembly approach was demonstrated by preparing LVO/rGO heterostructures using different assembling cations: Li+, Na+ and K+. The assembling cations influenced the interlayer spacings and structural water content of the resting LVO/rGO heterostructures. STEM/EELS analysis confirmed the formation of a 2D heterointerface between LVO and rGO for all types of the assembling cations used, with the assembling cations trapped in the interlayer regions. Additionally, STEM/EELS identified a V2O3 phase that formed at the LVO/rGO heterointerface and could stabilize the LVO/rGO heterostructures during cycling. Charge storage mechanism analysis indicated that increased interlayer spacings of the BVO phase and the use of assembling cations to define intercalation sites improved ion diffusion and increased capacities during cycling. Li+ and Na+ cation assembled heterostructures exhibited enhanced ion diffusion and charge storage capacities in their respective charge storage systems (Li-ion and Na-ion cells, respectively). Analyses of our results indicate that the choice of cation for heterostructure assembly can modify the final material structure and tailor ion diffusion and charge storage capacity for specific electrochemical systems, offering a versatile approach for utilizing 2D materials in energy storage applications.

Split G-Quadruplex Programmed Recyclable AIE-Biosensor for Label-Free Detection of miRNA in Acute Kidney Injury.

We herein rationally designed a target-recyclable AIE-biosensor based on a split G-quadruplex for label-free detection of miRNA in acute kidney injury. Initially, the PG was in an "OFF" state, and the two split segments (G4-a and G4-b) of G4 were tethered at the two terminals of P1 and far away from each other due to the rigid duplex structure formed by the partially complementary intermediate sequences of P2 and P1, bringing MG with quenched fluorescence. In the presence of target, the 5'-PO4 P2 was displaced from PG probe and competitively hybridized with target, which led to G4-a and G4-b tending to form an intact intermolecular G-quadruplex, providing sites for MG intercalation, thus generating an activated "ON" fluorescence signal due to the restriction of intermolecular motion. Successively, relying on the λ-exonuclease (λ-Exo) cleavage reaction-assisted target recycling, more amounts of targets will be liberated, accompanied by forming more G-quadruplex and binding more MG, resulting in a strong fluorescence signal, further realizing the sensitive detection of the targets. As a proof of concept, miRNA-21 was chosen as the model target. Endowing with the precise target recognition and efficient cleavage activity of λ-Exo, the AIE-biosensor exhibited excellent detection sensitivity and specificity, which could quantitatively detect miRNA-21 down to 10.36 fM with a single mismatch specificity. The results revealed that the distinctive attributes of noninvasive, simple, and efficient in this G-quadruplex-based AIE-biosensor offered promising prospects for extensive applications in AKI screening and early clinical diagnosis.

Sequence-Selective Recognition of the d(GGCGCC)2 DNA Palindrome by Oligopeptide Derivatives of Mitoxantrone. Enabling for Simultaneous Targeting of the Two Guanine Bases Upstream from the Central Intercalation Site in Both Grooves and along Both Strands.

The d(GGCGCC)2 palindrome is encountered in several oncogenic and retroviral sequences. In order to target it, we previously designed several oligopeptide derivatives of the mitoxantrone and ametantrone anticancer intercalators. These have two arms with a cationic side-chain in the major groove, each destined to bind along each strand O6/N7 of the two successive guanine bases (G1-G2/G1'-G2') upstream from the central anthraquinone intercalation site. We retained from a previous study (El Hage et al., 2022) a tris-intercalating molecule with two outer 9-aminoacridine (9-AA) intercalators, denoted as III. We sought enhancements in both affinity and selectivity by simultaneously targeting the minor groove of the extracyclic -NH2 groups of these bases and G4-G4' of the intercalation site. We considered derivatives of distamycin, having each pyrrole ring replaced by an imidazole to act as an in-register electron acceptor from the -NH2 group of a target guanine. We substituted the C6 and C7 carbons of anthraquinone, or the C8 and C9 ones of anthracycline, by an (imidazole-amide)3 chain. Four different derivatives of III were designed with different connectors to the anthraquinone/anthracycline and 9-AA. Polarizable molecular dynamics simulations of their complexes with a double-stranded DNA 18-mer with a central d(C GGGC GCCC G)2 palindrome sequence showed in-register minor groove binding to -NH2 of G1-G2/G1'-G2' to coexist with major groove recognition of O6/N7. Up to 12 H-bonds could be stabilized in the minor groove coexisting with four bidentate interactions of the alkyl diammonium moieties in the major groove. Since there is no mutual interference, the binding enthalpies, ΔH, contributed by each groove could add up and enable significant enhancements of the affinity constants. As was the case for their Lys precursor, these derivatives are amenable to chemical syntheses and in vitro and in vivo tests, for which the present results provide an incentive. The construction of derivatives III-A-III-D is modular. For in vitro experiments, this should enable unraveling the most important structural elements to further optimize both ΔH and TΔS and sequence selectivity and how this could translate to in vivo tests.

Intercalation Electrode and Grain Reconstruction Induce Significant Sensitivity Enhancement for Perovskite X-ray Detectors.

Organic-inorganic hybrid perovskites have been recognized as potential candidates in direct X-ray detectors and have triggered tremendous interest in the past years. The blade coating method meets the requirements of large area and low cost for perovskite X-ray detectors, while the low compactness resulting from solvent evaporation limits the charge collection efficiency (CCE) and device sensitivity. Most of the reports are focused on the melioration of perovskite films to increase device sensitivity; there are still problems of low CCE. Herein, we introduce an intercalation-electrode device structure and achieve a ∼20-fold sensitivity enhancement. Carrier distribution throughout the thick films is simulated, and the electrode intercalating site can be optimized according to the mobility-lifetime factor to achieve the highest CCE. A methylamine thiocyanate (MASCN) additive-assisted coating strategy is developed, and pinhole free thick films with regrown particles are obtained without frequently used hot/soft pressing. A sensitivity level of ∼105 μC Gyair-1 cm-2 as well as a detection limit of 77 nGyair s-1 is achieved under low bias, which is among the best performance for polycrystalline perovskite direct X-ray detectors. This work provides a universal device structure design to overcome carrier loss through a long transport distance and enhances the CCE for ultrahigh sensitivity.

Construction of foam-like carbon microspheres with controllable pseudo-graphitic domains: Synergistic enhancement of K-ion adsorption/intercalation storage

Hard carbon shows promise as a potassium-ion battery (PIB) anode, but its high capacity and rate property are limited by insufficient active sites and poor kinetics. Creating a porous channel structure offers an effective route, but such design often disrupts the development of intercalation sites critical for low-voltage plateau capacity, and may reduce the energy density of full cells. Herein, a staged pyrolysis strategy was developed to tailor foam-like carbon microspheres (FCMs) with controllable pseudo-graphitic domains by exploiting polymer with the temperature difference in pyrolysis. Such tactics perfectly retains abundant pseudo-graphitic domains and creates rich defect/pore structures, ensuring efficient K+ low-voltage intercalation and benefiting fast K+ transport. The optimized electrode exhibits balanced adsorption/intercalation capacity, delivering a large reversible capacity (386.7 mAh g−1 at 0.1C), outstanding rate performance (223.1 mAh g−1 at 4C) and excellent capacity retention (79.2 % over 2000 cycles at 4C). Additionally, the FCM-2//PTCDA full cell submits a high energy density of 198 Wh kg−1 and superb rate property/stability compared to same-type full cells. Tracked K-storage behavior confirmed the “adsorption–intercalation” mechanism and kinetic studies clarified that exact balance of defect, mesopore and pseudo-graphitic phase was crucial for the synergistic enhancement of adsorption/intercalation kinetics. This work opens up a unique method to tune the microstructure of hard carbon and offers design principles for developing practical anodes with synergistic storage behavior suitable for PIBs.

A mild, configurable, flexible CoNi-LDH(v)/Zn battery based on H-vacancy-induced reversible Zn2+ intercalation

Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage devices. However, the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered double hydroxide (CoNi-LDH) as the cathode material is hampered by their poor cycling stability and the corrosiveness of alkaline electrolytes. Herein, CoNi-LDH nanosheets enriched with H vacancies (CoNi-LDH(v)) were constructed on a flexible carbon cloth (CC) substrate via electrochemical deposition and activation. The Zn-based battery comprising CoNi-LDH(v)@CC as the cathode exhibited highly reversible conversion reactions and stable operation in 3 M ZnSO4 electrolyte (pH = 4). The battery delivered an excellent specific capacity (225 mA h g−1, 0.26 mA h cm−2), acceptable cycling stability (53.9%, 900 cycles), and high discharging voltage. The abundant H vacancies served as active sites for the reversible intercalation of Zn2+ and the extravasation of NO3− generated channels and space for Zn2+ transport and storage, together enabling an excellent Zn2+ storage capacity. Furthermore, a sandwich-structured solid-state CoNi-LDH(v)@CC//Zn@CC battery was fabricated and was found to exhibit a noteworthy electrochemical performance and mechanical durability. As a proof of concept, the unencapsulated battery powered a digital watch under various deformation conditions and operated stably for 80 h. Additionally, the flexible battery displayed outstanding customizability, maintaining an open-circuit voltage of 1.42 V even after being cut twice. The proposed engineering strategy contributes to the realization of textiles with truly wearable energy-storage devices.

Beyond lithium-ion batteries: Are effective electrodes possible for alkaline and other alkali elements? Exploring ion intercalation in surface-modified few-layer graphene and examining layer quantity and stages

In the pursuit of reliable energy storage solutions, the significance of engineering electrodes cannot be overstated. Previous research has explored the use of surface modifiers (SMs), such as single-side fluorinated graphene, to enhance the thermodynamic stability of ion intercalation when applied atop few-layer graphene (FLG). As we seek alternatives to lithium-ion batteries (LIBs), earth-abundant elements like sodium and potassium have emerged as promising candidates. However, a comprehensive investigation into staging intercalation has been lacking thus far. By delving into staging assemblies, we have uncovered a previously unknown intercalation site that offers the most energetically favorable binding. Here, we study the first three elements in both alkali (Li, Na, K) and alkaline (Be, Mg, Ca) earth metals. Furthermore, the precise mechanism underlying this intercalation system has remained elusive in prior studies. In our work, we employed density functional theory calculations with advanced hybrid functionals to determine the electrical properties at various stages of intercalation. This approach has been proven to yield more accurate and reliable electrical information. Through the analysis of projecting density of states and Mulliken population, we have gained valuable insights into the intricate interactions among the SM, ions, and FLG as the ions progressively insert into the structures. Notably, we expanded our investigation beyond lithium and explored the effectiveness of the SM on ions with varying radii and valence, encompassing six alkali and alkaline earth metals. Additionally, we discovered that the number of graphene layers significantly influences the binding energy. Our findings present groundbreaking concepts for material design, offering diverse and economically viable alternatives to LIBs. Furthermore, they serve as a valuable reference for fine-tuning electrical properties through staging intercalation and the application of SMs.

Balancing Graphitic Nanodomains and Heteroatom Doping in Hard Carbons Toward High Capacity and Durable Potassium‐Ion Battery Anodes

AbstractHard carbons (HCs) have emerged as promising candidates for commercial anodes in potassium‐ion batteries (PIBs). However, a thorny challenge remains in achieving high reversible capacities at high charge/discharge rates, which significantly hinders the development of HCs for PIBs. Here, a temperature‐controlled strategy is proposed to effectively balance graphitic nanodomains and heteroatom doping content in HCs, resulting in widened carbon layer spacing, high conductivity, and abundant K‐ion intercalation sites. The optimized NO‐HC600 electrode exhibits a high reversible capacity of 315.0 mAh g−1 at 0.2 A g−1, and exceptional cyclic stability (235.0 mAh g−1 after 1200 cycles at 2.0 A g−1 with a capacity retention rate of 98.82%). Furthermore, systematic in /ex situ experiments unveil a highly reversible “adsorption–intercalation” mechanism governing potassium‐ion storage, confirming the origin of the superior performance. This work offers valuable insights into the facile preparation of HC anodes with high reversible capacity and fast charge/discharge capability for PIBs.

Pore Network Modelling of a Lithium Ion Battery Cathode as a Tool for Microstructure Optimization

Lithium ion batteries (LIBs) have become the battery of choice, owning almost 90% of the energy storage market [1]. They boast excellent power and energy density, but performance decreases at high discharge rates limiting their use in large scale applications [2]. With the availability of graphite and silicon materials as anode, the anode in a lithium-ion battery is already well optimized and research has focused primarily on the development of cathode materials with high rate-capacity. A LIB cathode is a porous material comprised of electrolyte, active material, and carbon binder phases. The electrolyte facilitates the migration and diffusion of lithium ions from the anode, through a porous separator, and to the active material where lithium ions intercalate, and electronic current is produced as the battery discharges. A carbon binder phase is also dispersed to enhance the electrical conductivity of the cathode and may even contain micropores that can increase current density [3]. The porous microstructure of a LIB cathode thereby plays an important role in controlling the movement of lithium ions and accessibility of active material effecting both discharge rate and capacity of LIBs. Therefore, tailoring the cathode microstructure provides a route for LIB cathode optimization. Pore scale models that resolve the electrolyte, active material, and carbon binder phases in a cathode can be used for this purpose. Pore scale models offer unique advantages compared to experimental studies in that they can test a wide variety of microstructures, even ones that are not yet realized, in a relatively short time frame. Typical battery models are continuum models that do not resolve the pore space and instead use effective properties determined from experiment. Pore scale models do not use effective properties saving experimental effort but are disadvantageous in that they are computationally very expensive requiring a fine mesh on a highly resolved volumetric image. Of the pore-scale modeling options, pore network modelling (PNM) is an especially efficient approach that discretizes the microstructure into pores and throats where pores are the computational nodes and throats are constrictions connecting pores [4]. In the literature, there is only one known pore network model of a LIB cathode, but it is an isothermal model that does not consider the effect of heat generation from electrochemical reactions [5]. While this model was effective at predicting discharge performance at low currents, predicting the voltage for galvanostatic discharge at high currents proved to be difficult, possibly because of assumed isothermal behaviour. Therefore, this work is focused on the development of a non-isothermal pore network model of a LIB cathode undergoing galvanostatic discharge. The complete set of partial differential equations and their discretization’s for modelling lithium transport, ionic or electronic charge transport, as well as heat transfer in all three phases of a LIB cathode is presented along with the numerical framework used for solving the coupled physics. This framework and discretized set of equations are demonstrated on a pore network extracted from an X-ray tomography image of a NMC532 cathode. Post-processing of the extracted network is done to apply novel interphase nodes between active material and electrolyte phases to provide sites for lithium intercalation to occur. The pore network model is written in Python using OpenPNM, an open-source pore network modelling package [6].[1] S. Zavahir et al., “A review on lithium recovery using electrochemical capturing systems,” Desalination, vol. 500, Mar. 2021, doi: 10.1016/j.desal.2020.114883.[2] R. Wagner, N. Preschitschek, S. Passerini, J. Leker, and M. Winter, “Current research trends and prospects among the various materials and designs used in lithium-based batteries,” J Appl Electrochem, vol. 43, no. 5, pp. 481–496, May 2013, doi: 10.1007/S10800-013-0533-6/FIGURES/10.[3] Z. A. Khan et al., “Probing the Structure-Performance Relationship of Lithium-Ion Battery Cathodes Using Pore-Networks Extracted from Three-Phase Tomograms,” J Electrochem Soc, 2020, doi: 10.1149/1945-7111/ab7bd8.[4] M. McKague, H. Fathiannasab, M. Agnaou, M. A. Sadeghi, and J. Gostick, “Extending pore network models to include electrical double layer effects in micropores for studying capacitive deionization,” Desalination, vol. 535, 2022, doi: 10.1016/j.desal.2022.115784.[5] Z. A. Khan, M. Agnaou, M. A. Sadeghi, A. Elkamel, and J. T. Gostick, “Pore Network Modelling of Galvanostatic Discharge Behaviour of Lithium-Ion Battery Cathodes,” J Electrochem Soc, vol. 168, no. 7, Jul. 2021, doi: 10.1149/1945-7111/ac120c.[6] J. Gostick et al., “OpenPNM: A Pore Network Modeling Package,” Comput Sci Eng, vol. 18, no. 4, pp. 60–74, Jul. 2016, doi: 10.1109/MCSE.2016.49. Figure 1

Investigating Cathode Dynamics in Realistic Desalination Reactors Using Operando High-Energy Synchrotron X-Ray Microscopy

Four billion people suffer from lack of clean water at least one month of the year.[1] This critical water shortage applies not only to the supply of potable water, but also to water for use in industrial, agricultural, and energy applications. While water resources like seawater are abundant, hardly any water resource is clean enough for direct use. Desalination provides a methodology to render unusable waters from such water resources fit for use. An innovative and particularly energy-efficient electrochemistry-based approach is the Desalination Battery (DB), which stores the energy input during desalination in chemical bonds between ions and faradaic electrode, allowing for its recovery during the salination process. DBs are at the forefront of the water-energy nexus[2]. While they are promising for seawater desalination (e.g., for seawater to brackish water conversion), practical implementation and their full potential still need to be unlocked. To this end, foundational understanding of the atomic- to electrode-scale physics/chemistry underlying functionality and degradation must be unraveled.Towards this end, we utilized our unique flow-by reactor setup to combine electrochemistry, conductivity, and temperature measurements with high-energy (75 keV) operando synchrotron X-ray diffraction (HEXRD) microscopy. Our investigation encompasses both the atomic and electrode levels, using a 3-electrodes setup with LiMn2O4 and Na0.44MnO2 as electrode active materials. As such, we were able to simulate a realistic electrode environment for operando measurements, as well as observe spatially resolved structural changes by scanning the beam across the electrodes surface. These phenomena are manifested through changes in unit cell parameters and the emergence of new phases during desalination cycles. Specifically, we tracked the changes in XRD patterns over the course of several desalination cycles in LiCl and NaCl solutions, as well as synthetic seawater and mixed solutions of LiCl/MgCl2. We were able to observe high selectivity of LiMn2O4 towards Li+, even in the highly concentrated synthetic seawater solutions, and could not observe the emergence of a new Mg+ rich phase down to potentials of 0 V vs. AgCl. Na0.44MnO2 exhibited good cycling behavior in synthetic seawater akin to pure NaCl solutions, and apart from the Na+ rich phase showed no signs of additional new phases, suggesting a highly selective nature towards Na+. Furthermore, we compared constant current and constant potential protocols and observed distinct differences in peak shift behavior. Ongoing analysis of the unit cell parameters and atomic positions allows us to allocate specific intercalation sites to specific potentials, providing foundational insight into the chemistry and physics underlying the selectivity of these materials.Literature:[1] M. M. Mekonnen, et al., Sci Adv 2016, 2, e1500323.[2] Q. Li, et al., Adv Sci (Weinh) 2020, 7, 2002213.

Determination of Electrochemically Active Surface Area in All-Solid-State Batteries

All-solid-state batteries (ASSBs) are currently receiving much attention as one of the most promising next-generation rechargeable battery systems due to their promise of high energy density and high safety. Despite many efforts to commercialize ASSBs, however, there are still many unresolved technical challenges. Unlike conventional lithium-ion batteries (LIBs), the interface between the cathode and electrolyte in ASSBs exhibits a complex degradation pattern that combines chemical and mechanical degradations. In particular, the high Ni content cathode materials in ASSBs are commonly known to suffer from significant additional degradation mechanism, e.g., volume expansion/contraction due to H2-H3 phase transitions at high voltages, resulting in particle cracking. This degradation of the integrity of the active material leads to a reduction in electrochemically active surface area (active area afterward) due to loss of contact between the active material and solid electrolyte, slow diffusion rate of lithium in the active material, and isolation of the active material. These issues are recognized as major contributors to cell performance degradation. Among these issues, the changes in the active area have a decisive impact on the rate of redox reactions that are key to battery charging and discharging kinetics, so accurate determination of the active area is crucial for the diagnosis and improvement of batteries. In the electrochemical analysis of ASSBs, the poor contact between the solid electrolyte and the active material, or the change of the contact properties during the battery operation, should be a very important consideration. Especially when determining kinetic factors such as charge transfer resistance and chemical diffusion coefficient of cathode material by electrochemical methods, the models we usually use include the electrode surface area value as an important variable, so the accurate estimation of the active area is indispensable for obtaining reliable electrochemical properties. Unlike typical LIBs, in ASSBs the active material/electrolyte interface contact properties change relatively significantly during repeated cycling, so devising a reliable technique to analyze the active area of active materials in ASSBs is very crucial for the research and development of ASSBs. However, to the best of our knowledge, there are still very few studies on this.In this study, we propose promising methods to measure the contact characteristics between the cathode material and the solid electrolyte in ASSBs, namely the electrochemically active surface area, and discuss their reliability based on intercomparison and literature reports. For this purpose, first, the method for determining the active area of active materials based on galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) reported in conventional LIBs was reviewed. Then, its applicability to ASSBs was explored, and a way to improve the reliability of the analysis was proposed. Specifically, a three-electrode cathode half-cell experiment was conducted to analyze the active area of the Ni-rich cathode. The active area was calculated by comparing the diffusion coefficient measured by EIS with that obtained by GITT. When comparing the active area determined at different voltages, it was observed that the active area varies significantly with voltage most likely due to the volume change caused by the H2-H3 phase transition. The second electrochemical method performed for the determination of the active area of the active material is based on the quantification of the lithium intercalation sites on the cathode surface based on the analysis of the frequency factor in Arrhenius expression. For this purpose, battery at different charge states were kept at high temperatures for long periods of time to induce interfacial degradation. The temperature-dependent charge transfer resistance was then determined by EIS analysis, which was used to interpret the redox (or lithium absorption/desorption) reactions kinetically. The experimental results showed that the redox reaction rate followed exactly the Arrhenius relationship for all the charge states used, but the activation energies and frequency factors changed differently depending on the charge state. In this study, we discuss these results in relation to various phenomena that may occur during high-temperature aging, such as the formation of rock salt structures and cracks on the nickel-rich cathode surface, and try to estimate the change in active area. In this study, the electrochemical analysis methods of the contact characteristics between the cathode and the solid electrolyte in ASSBs will be examined in depth and their reliability will be assessed. In addition, further improvements in active area analysis techniques for active materials in ASSBs will be discussed.