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MnO2 materials are considered promising cathode materials for rechargeable lithium, sodium, and magnesium batteries due to their earth abundance and environmental friendliness. One polymorph of MnO2, α-MnO2, has 2 × 2 tunnels (4.6 A × 4.6 A) in its structural framework, which provide facile diffusion pathways for guest ions. In this work, a silver-ion-containing α-MnO2 (Ag1.2Mn8O16) is examined as a candidate cathode material for Li based batteries. Electrochemical stability of Ag1.2Mn8O16 is investigated through Coulombically controlled reduction under 2 or 4 molar electron equivalents (e.e.). Terminal discharge voltage remains almost constant under 2 e.e. of cycling, whereas it continuously decreases under repetitive reduction by 4 e.e. Thus, detailed structural analyses were utilized to investigate the structural evolution upon lithiation. Significant increases in lattice a (17.7%) and atomic distances (∼4.8%) are observed when x in LixAg1.2Mn8O16 is >4. Ag metal forms at this level of lithiation conco...

Battery electrodes are complex mesoscale systems comprised of an active material, conductive agent, current collector, and polymeric binder. Previous work showed that introduction of poly [3-(potassium-4-butanoate) thiophene] (PPBT) as a binder component coupled with a polyethylene glycol (PEG) surface coating on magnetite (Fe 3 O 4 ) nanoparticles enhanced electron and ion transport in the high capacity anode system. Here, the impact of Fe 3 O 4 crystallite size (10 nm vs. 20 nm) and surface chemistry were explored to evaluate their effects on interfacial interactions within the composite PEG/PPBT based electrodes and resultant battery performance. The Fe 3 O 4 synthesis methods inevitably lead to differences in surface chemistry. For instance, the Fe 3 O 4 particles synthesized using ammonium hydroxide appeared more dispersed, and afforded improved rate capability performance. Notably, chemical interactions between the active nanoparticles and PPBT binder were only seen with particles synthesized using triethylamine. Capacity retention and cycling performance were unaffected. This study provides fundamental insights into the significant impact of active material synthesis on the design and fabrication of composite battery electrodes.

α-MnO2-structured materials are generally classified as semiconductors; thus, we present a strategy to increase electrochemical utilization through the design of a conductive material interface. Surface treatment of silver hollandite (AgxMn8O16) with Ag+ (Ag2O) provides significant benefits to the resultant electrochemistry, including a decreased charge-transfer resistance and a 2-fold increase in deliverable energy density at a high rate. The improved function of this designed interface relative to conventional electrode fabrication strategies is highlighted.

Advances in liquid-phase exfoliation and surfactant-directed anisotropic growth of two-dimensional (2D) nanosheets have enabled their rapid development. However, it remains challenging to develop assembly strategies that lead to the construction of 2D nanomaterials with well-defined geometry and functional nanoarchitectures that are tailored to specific applications. Here we report a facile self-assembly method leading to the controlled synthesis of 2D transition metal oxide (TMO) nanosheets containing a high density of holes. We utilize graphene oxide sheets as a sacrificial template and Pluronic copolymers as surfactants. By using ZnFe2O4 (ZFO) nanoparticles as a model material, we demonstrate that by tuning the molecular weight of the Pluronic copolymers we can incorporate the ZFO particles and tune the size of the holes in the sheets. The resulting 2D ZFO nanosheets offer synergistic characteristics including increased electrochemically active surface areas, shortened ion diffusion paths, and strong i...

Solid electrolytes (SEs) are a promising, safe alternative to liquid electrolytes in high energy density batteries, but challenges, including low ionic conductivity and dendrite formation, remain. In a recent work, it was determined that dendrite formation within representative SEs, Li7La3Zr2O12 and Li3PS4, is due to their non-negligible electronic conductivity.[1] Notably, LiI has negligible electronic conductivity and thus the formation of lithium dendrites may be lessened, making LiI a good candidate for SE development. Our previous work on LiI SE, utilized 1:2 lithium iodide:3-hydroxypropionitrile (LiI(HPN)2) as a conductive additive, creating an 80/20 LiI/LiI(HPN)2 composite as a self-forming, rechargeable battery.[3] Additional work has demonstrated interfacial modification can effectively lower the cell impedance and improve coulombic efficiency (CE).[2, 4] In this work, a LiI SE was improved by reducing particle size via several processing methods; grinding (G), sonicating (C-S), and grinding with sonicating (G-S), and compared to a control (C) sample of LiI which underwent no processing. Partial hydration of LiI results in increased conductivity via increased defect density, and thus this parameter was controlled to ca. 34 mol% LiI monohydrate between samples. With further processing, particle size was reduced from 5 ± 1 µm to 2.0 ± 0.2 µm for the C and G-S samples. Utilized in 80/20 LiI/LiI(HPN)2 composites, reducing particle size resulted in an order of magnitude increase in ionic conductivity, from 7.7 x 10-8 to 6.1 x 10-7 S cm-1, at room temperature. Improved conductivity is attributed to an increased number of grain boundaries and defects, enabling ion transport and better mixing with the electrolyte additive, LiI(HPN)2. 3D confocal Raman spectroscopy in conjunction with non-negative matrix factorization (NMF) analysis determined the degree of HPN aggregation was lessened in the sample with smallest particle size. This LiI SE was utilized in a self-forming Li/I2 battery, where reduced particle size (improved conductivity) led to significantly reduced overpotential, allowing the coulombic efficiency to reach 100% in the first cycle. The G-S cells also exhibited improved electrochemical function when cycling at higher rates compared with the other electrolyte types. This work demonstrates the effect of particle size on solid electrolyte in a self-forming, self-healing, all solid state battery with a lithium metal negative electrode. References [1] F. Han, A.S. Westover, J. Yue, X. Fan, F. Wang, M. Chi, D.N. Leonard, N.J. Dudney, H. Wang, C. Wang, High electronic conductivity as the origin of lithium dendrite formation within solid electrolytes, Nature Energy, 4 (2019) 187-196. [2] C.A. Stackhouse, A. Abraham, S. Yan, L. Wang, N. Sadique, G. Singh, A.C. Marschilok, E.S. Takeuchi, K.J. Takeuchi, Self-Healing, Improved Efficiency Solid State Rechargeable Li/I2 Based Battery, Journal of The Electrochemical Society, 168 (2021). [3] A. Abraham, J. Huang, P.F. Smith, A.C. Marschilok, K.J. Takeuchi, E.S. Takeuchi, Communication—Demonstration and Electrochemistry of a Self-Forming Solid State Rechargeable LiI(HPN)2Based Li/I2Battery, Journal of The Electrochemical Society, 165 (2018) A2115-A2118. [4] A. Abraham, M.R. Dunkin, J. Huang, B. Zhang, K.J. Takeuchi, E.S. Takeuchi, A.C. Marschilok, Interface effects on self-forming rechargeable Li/I2-based solid state batteries, MRS Communications, 9 (2019) 657-662.

Zero-strain electrodes, such as spinel lithium titanate (Li4/3Ti5/3O4), are appealing for application in batteries due to their negligible volume change and extraordinary stability upon repeated charge/discharge cycles. On the other hand, this same property makes it challenging to probe their structural changes during the electrochemical reaction. Herein, we report in situ studies of lithiation-driven structural transformations in Li4/3Ti5/3O4 via a combination of X-ray absorption spectroscopy and ab initio calculations. Based on excellent agreement between computational and experimental spectra of Ti K-edge, we identified key spectral features as fingerprints for quantitative assessment of structural evolution at different length scales. Results from this study indicate that, despite the small variation in the crystal lattice during lithiation, pronounced structural transformations occur in Li4/3Ti5/3O4, both locally and globally, giving rise to a multi-stage kinetic process involving mixed quasi-solid s...

Spinel ferrites such as CuFe2O4, Fe3O4 and ZnFe2O4 are promising anode materials for lithium-ion batteries due to their high theoretical capacities, natural elemental abundances and nontoxicity. Although these spinels are from a related family of materials, there are differences among their cation arrangements, thus, providing an opportunity to study their redox mechanisms during lithiation and delithiation. X-ray Absorption Spectroscopy (XAS) techniques which analyze x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) offer insight into both local geometry and electronic structure of the absorbing atom. Additionally, when combined with x-ray microscopy, these methods can detect subtle electronic changes at resolutions as low as 10 nm. With this level of insight, XAS is a necessary tool to probe the redox mechanism of the spinel ferrites. Herein, the ex-situ XAS analysis of spinel ferrites is described to highlight the changes to the metal centers during discharge and charge.

With a theoretical capacity exceeding 900 mAh/g, magnetite (Fe3O4) is an interesting anode material for lithium ion batteries. This report highlights observations relating to charge transfer capabilities of Fe3O4 over several length scales. Ex-situ extended x-ray absorption fine structure (EXAFS) and transmission electron microscopy (TEM) data provide the foundation for study of the atomic-scale mechanism. The function of the Fe3O4 electrode material is studied both in nanometer sized particles (as observed by TEM), and in micron sized aggregates (as observed by transmission x-ray microscopy (TXM)). Notably, the recent development of electrically conducting binders towards modification of mesoscale electrode composition and structure demonstrates significant gains in capacity and capacity retention, despite utilizing the same Fe3O4 particles.

The formation of conductive metallic silver upon electrochemical reduction and lithiation of Ag7Fe3(P2O7)4 is investigated. Alternating current impedance spectroscopy measurements show a 34% decrease in charge transfer resistance upon one electron equivalent (ee) of reduction, which is coincident with the formation of a Ag metal conductive network evidenced by both ex situ and operando X-ray diffraction. Quantitative assessment of Ag metal formation derived from operando XRD shows that only Ag+ ions are reduced during the first 3ee, followed by simultaneous reduction of Ag+ and Fe3+ reduction for the next 5ee (3ee to 8ee), culminating in reduction of the remaining Ag+. Scanning electron microscopy images show smaller Ag metal crystallite size and shorter nearest neighbor distance between and among Ag particles with higher depth of discharge. A high rate intermittent pulsatile discharge test is conducted where the cell delivers 12 total pulses during full discharge to probe the effect of Ag metal formation...

For the Lithium-Sulfur (Li-S) battery to be competitive in commercialization, it is requested that the sulfur electrode must have deliverable areal capacity > 8 mAh cm−2, which corresponds to a sulfur loading > 6 mg cm−2. At this relatively high sulfur loading, we evaluated the impact of binder and carbon type on the mechanical integrity and the electrochemical properties of sulfur electrodes. We identified hydroxypropyl cellulose (HPC) as a new binder for the sulfur electrode because it offers better adhesion between the electrode and the aluminum current collector than the commonly used polyvinylidene fluoride (PVDF) binder. In combination with the binder study, multiple types of carbon with high specific surface area were evaluated as sulfur hosts for high loading sulfur electrodes. A commercial microporous carbon derived from wood with high pore volume showed the best performance. An electrode with sulfur loading up to 10 mg cm−2 was achieved with the optimized recipe. Based on systematic electrochemical studies, the soluble polysulfide to insoluble Li2S2/Li2S conversion was identified to be the major barrier for high loading sulfur electrodes to achieve high sulfur utilization.

We report an extensive study on fundamental properties that determine the functional electrochemistry of ZnFe2O4 spinel (theoretical capacity of 1000 mAh/g). For the first time, the reduction mechanism is followed through a combination of in situ X-ray diffraction data, synchrotron based powder diffraction, and ex-situ extended X-ray absorption fine structure allowing complete visualization of reduction products irrespective of their crystallinity. The first 0.5 electron equivalents (ee) do not significantly change the starting crystal structure. Subsequent lithiation results in migration of Zn2+ ions from 8a tetrahedral sites into vacant 16c sites. Density functional theory shows that Li+ ions insert into 16c site initially and then 8a site with further lithiation. Fe metal is formed over the next eight ee of reduction with no evidence of concurrent Zn2+ reduction to Zn metal. Despite the expected formation of LiZn alloy from the electron count, we find no evidence for this phase under the tested conditi...

Multiple lithium-ion transport pathways and local phase changes upon lithiation in silver hollandite are revealed via in situ microscopy including electron diffraction, imaging and spectroscopy, coupled with density functional theory and phase field calculations. We report unexpected inter-nanorod lithium-ion transport, where the reaction fronts and kinetics are maintained within the neighbouring nanorod. Notably, this is the first time-resolved visualization of lithium-ion transport within and between individual nanorods, where the impact of oxygen deficiencies is delineated. Initially, fast lithium-ion transport is observed along the long axis with small net volume change, resulting in two lithiated silver hollandite phases distinguishable by orthorhombic distortion. Subsequently, a slower reaction front is observed, with formation of polyphase lithiated silver hollandite and face-centred-cubic silver metal with substantial volume expansion. These results indicate lithium-ion transport is not confined within a single nanorod and may provide a paradigm shift for one-dimensional tunnelled materials, particularly towards achieving high-rate capability., Hollandite structured materials are potentially useful for battery technologies. Here the authors report the unusual lateral transport of lithium ions between lithiated silver manages oxide nanorods where the reaction fronts and kinetics are maintained within the neighbouring nanorods.

Background & Aims The sodium taurocholate co-transporting polypeptide (NTCP) is the main target of most hepatitis B virus (HBV) specific entry inhibitors. Unfortunately, these agents also block NTCP transport of bile acids into hepatocytes, and thus have the potential to cause adverse effects. We aimed to identify small molecules that inhibit HBV entry while maintaining NTCP transporter function. Methods We characterized a series of cyclosporine (CsA) derivatives for their anti-HBV activity and NTCP binding specificity using HepG2 cells overexpressing NTCP and primary human hepatocytes. The four most potent derivatives were tested for their capacity to prevent HBV entry, but maintain NTCP transporter function. Their antiviral activity against different HBV genotypes was analysed. Results We identified several CsA derivatives that inhibited HBV infection with a sub-micromolar IC 50 . Among them, SCY446 and SCY450 showed low activity against calcineurin (CN) and cyclophilins (CyPs), two major CsA cellular targets. This suggested that instead, these compounds interacted directly with NTCP to inhibit viral attachment to host cells, and have no immunosuppressive function. Importantly, we found that SCY450 and SCY995 did not impair the NTCP-dependent uptake of bile acids, and inhibited multiple HBV genotypes including a clinically relevant nucleoside analog-resistant HBV isolate. Conclusions This is the first example of small molecule selective inhibition of HBV entry with no decrease in NTCP transporter activity. It suggests that the anti-HBV activity can be functionally separated from bile acid transport. These broadly active anti-HBV molecules are potential candidates for developing new drugs with fewer adverse effects. Lay summary In this study, we identified new compounds that selectively inhibited hepatitis B virus (HBV) entry, and did not impair bile acid uptake. Our evidence offers a new strategy for developing anti-HBV drugs with fewer side effects.

Li1.1V3O8 is a promising cathode material for Li-ion batteries, because of its high theoretical capacity (362 mAh g–1) and good rate performance. In this study, the structural evolution of Li1.1V3O8 material during electrochemical dis(charge) processes was investigated using a combination of theoretical calculations and experimental data. Density functional theory (DFT) was used to predict the intermediate structures at various lithiation states, as well as the stability of major phases. In order to validate these predictions, in situ X-ray diffraction (XRD) data was collected operando, allowing for the phase transformations to be monitored under current load and eliminating the possibilities of structural relaxation processes and environmental oxidation. Rietveld refinement was performed to fit the diffraction data with the DFT-derived structures and to analyze the fractions of major phases as a function of dis(charge). The DFT calculations identified three stable states that were validated by the in sit...

Cryptomelane type manganese dioxides (α-MnO2, OMS-2) are interesting potential cathode materials due to the ability of their one dimensional (1D) tunnels to reversibly host various cations including Li+ and an accessible stable 3+/4+ redox couple. Here, we synthesized metal cation free OMS-2 materials where the tunnels were occupied by only water and hydronium ions. Water was subsequently removed from the tunnels. Cation free OMS-2 and Dry-OMS-2 were used as cathodes in Li based batteries to investigate the role of tunnel water on their electrochemistry. The initial discharge capacity was higher for Dry-OMS-2 (252 mAh/g) compared to OMS-2 (194 mAh/g), however, after 100 cycles Dry-OMS-2 and OMS-2 delivered 137 mAh/g and 134 mAh/g, respectively. Li+ ion diffusion was more facile for Dry-OMS as evidenced by rate capability, at 400 mA/g. Dry-OMS-2 delivered 135mAh/g whereas OMS-2 delivered ~115 mAh/g. This first report of the impact of tunnel water on the electrochemistry of OMS-2 type materials demonstrates that the presence of tunnel water in OMS-2 type materials negatively impacts the electrochemistry.

In this study, we conducted the first energy dispersive x-ray diffraction (EDXRD) experiments on Li/Li1.1V3O8 coin cells discharged to different lithiation levels in order to investigate the phase transitions upon electrochemical reduction. The phase transformation from layered Li-poor α to Li-rich α to defect rock-salt β phase was confirmed with cells of different lithiation stages. No spatial localization of phase formation was observed throughout the cathodes under the conditions of this measurement.

Ag7Fe3(P2O7)4 is a 3D structured material which has been recently studied as a possible cathode material for lithium batteries. Notably, Na7Fe3(P2O7)4 is reported to be a fast-ion conductor, yet poor electrical conductor. Here, partial replacement of Na+ for Ag+ yielded Na2Ag5Fe3(P2O7)4 pyrophosphate framework where the formation of Ag metal is proposed to increase the intrinsic low electrical conductivity of this polyanion electrode. Specifically, the Ag5Na2Fe3(P2O7)4 -Ag composite is synthesized via chemical reduction of Ag7Fe3(P2O7)4 using NaBH4. The occupancy of Ag+ and Na+ in each site was determined via Rietveld analysis of the diffraction pattern. Electrochemistry of the Ag5Na2Fe3(P2O7)4 -Ag metal composite was explored with voltammetry and galvanostatic charge/discharge cycling. The Ag5Na2Fe3(P2O7)4 -Ag metal composite electrodes displayed good rate capability assisted by the presence of Ag metal from the chemical reduction and in-situ electrochemical formation of a Ag conductive network.

The iron oxide magnetite, Fe3O4, is a promising conversion type lithium ion battery anode material due to its high natural abundance, low cost and high theoretical capacity. While the close packing of ions in the inverse spinel structure of Fe3O4 enables high energy density, it also limits the kinetics of lithium ion diffusion in the material. Nanosizing of Fe3O4 to reduce the diffusion path length is an effective strategy for overcoming this issue and results in improved rate capability. However, the impact of nanosizing on the multiple structural transformations that occur during the electrochemical (de)lithiation reaction in Fe3O4 is poorly understood. In this study, the influence of crystallite size on the lithiation-conversion mechanisms in Fe3O4 is investigated using complementary X-ray techniques along with transmission electron microscopy (TEM) and continuum level simulations on electrodes of two different Fe3O4 crystallite sizes. In situ X-ray diffraction (XRD) measurements were utilized to track the changes to the crystalline phases during (de)lithiation. X-ray absorption spectroscopy (XAS) measurements at multiple points during the (de)lithiation processes provided local electronic and atomic structural information. Tracking the crystalline and nanocrystalline phases during the first (de)lithiation provides experimental evidence that (1) the lithiation mechanism is non-uniform and dependent on crystallite size, where increased Li+ diffusion length in larger crystals results in conversion to Fe0 metal while insertion of Li+ into spinel-Fe3O4 is still occurring, and (2) the disorder and size of the Fe metal domains formed when either material is fully lithiated impacts the homogeneity of the FeO phase formed during the subsequent delithiation.

Zinc ferrite (ZnFe2O4) is a prospective lithium ion battery (LIB) material, owing to its large theoretical capacity (1000 mA h g−1). Here, we report a density functional study of the discharge process at an early stage from ZnFe2O4 up to LixZnFe2O4 (x = 2), aiming to provide a fundamental understanding of the mechanism. According to our calculations, with x increasing up to 1 the intercalation of Li+ ions prefers octahedral 16c sites, which is accompanied by Zn2+ ion displacement from tetrahedral 8a sites to 16c sites starting at x = 0.25 and a gain in stability, while the stability decreases for 1 < x ≤ 2 due to the occupation of Li+ ions at the less active tetrahedral 8a/48f/8b sites. The open-circuit voltages estimated based on the structures of stable intermediates identified by DFT calculations are in good agreement with the experimental values. Our results highlight the importance of the interplay among Li, O2−, Fe3+ and Zn2+ in enabling their high performance as LIB materials.

Magnetite is a conversion anode material displaying multi-electron transfer during lithiation and delithiation. The solid electrolyte interphase (SEI) on magnetite, Fe3O4, electrodes for lithium ion batteries was deliberately modified through the use of fluoroethylene carbonate (FEC) electrolyte additive, improving both capacity retention and rate capability. Analysis showed reduction of FEC at higher voltage compared to non-fluorinated solvents with formation of a modified lithium flouride containing electrode surface.

Li1+nV3O8 (n = 0-0.2) has been extensively investigated as a cathode material for Li ion batteries because of its superior electrochemical properties including high specific energy and good rate capability. In this paper, a synchrotron based energy dispersive X-ray diffraction (EDXRD) technique was employed to profile the phase transitions and the spatial phase distribution of a Li1.1V3O8 electrode during electrochemical (de)lithiation in situ and operando. As annealing temperature during the preparation of the Li1.1V3O8 material has a strong influence on the morphology and crystallinity, and consequently influences the electrochemical outcomes of the material, Li1.1V3O8 materials prepared at two different temperatures, 500 and 300 °C (LVO500 and LVO300), were employed in this study. The EDXRD spectra of LVO500 and LVO300 cells pre-discharged at C/18, C/40 and C/150 were recorded in situ, and phase localization and relative intensity of the peaks were compared. For cells discharged at the C/18 rate, although α and β phases were distributed uniformly within the LVO500 electrode, they were localized on two sides of the LVO300 electrode. Discharging rates of C/40 and C/150 led to homogeneous β phase formation in both LVO500 and LVO300 electrodes. Furthermore, the phase distribution as a function of position and (de)lithiation extent was mapped operando as the LVO500 cell was (de)lithiated. The operando data indicate that (1) the lithiation reaction initiated from the side of the electrode facing the Li anode and proceeded towards the side facing the steel can, (2) during discharge the phase transformation from a Li-poor to a Li-rich α phase and the formation of a β phase can proceed simultaneously in the electrode after the first formation of a β phase, and (3) the structural evolution occurring during charging is not the reverse of that during discharge and takes place homogenously throughout the electrode.

Investigation of the tensile and fatigue properties of cast magnesium alloys, created by the heated mold continuous casting process (HMC), was conducted. The mechanical properties of the Mg-HMC alloys were overall higher than those for the Mg alloys, made by the conventional gravity casting process (GC), and especially excellent mechanical properties were obtained for the Mg97Y2Zn1-HMC alloy. This was because of the fine-grained structure composed of the α-Mg phases with the interdendritic LPSO phase. Such mechanical properties were similar levels to those for conventional cast aluminum alloy (Al84.7Si10.5Cu2.5Fe1.3Zn1 alloys: ADC12), made by the GC process. Moreover, the tensile properties (σUTS and εf) and fatigue properties of the Mg97Y2Zn1-HMC alloy were about 1.5 times higher than that for the commercial Mg90Al9Zn1-GC alloy (AZ91). The high correlation rate between tensile properties and fatigue strength (endurance limit: σl) was obtained. With newly proposed etching technique, the residual stress in the Mg97Y2Zn1 alloy could be revealed, and it appeared that the high internal stress was severely accumulated in and around the long-period stacking-order phases (LPSO). This was made during the solidification process due to the different shrinkage rate between α-Mg and LPSO. In this etching technique, micro-cracks were observed on the sample surface, and amount of micro-cracks (density) could be a parameter to determine the severity of the internal stress, i.e., a large amount to micro-cracks is caused by the high internal stress.

Spectroscopic factors of neutron-hole and proton-hole states in ^{131}Sn and ^{131}In, respectively, were measured using one-nucleon removal reactions from doubly magic ^{132}Sn at relativistic energies. For ^{131}In, a 2910(50)-keV γ ray was observed for the first time and tentatively assigned to a decay from a 5/2^{-} state at 3275(50) keV to the known 1/2^{-} level at 365 keV. The spectroscopic factors determined for this new excited state and three other single-hole states provide first evidence for a strong fragmentation of single-hole strength in ^{131}Sn and ^{131}In. The experimental results are compared to theoretical calculations based on the relativistic particle-vibration coupling model and to experimental information for single-hole states in the stable doubly magic nucleus ^{208}Pb.

While the focus of research related to the design of robust, high-performance Li-ion batteries relates primarily to the synthesis of active particles, the binder plays a crucial role in stability and ensures electrode integrity during volume changes that occur with cycling. Conventional polymeric binders such as poly(vinylidene difluoride) generally do not interact with active particle surfaces and fail to accommodate large changes in particle spacing during cycling. Thus, attention is now turning toward the exploration of interfacial interactions between composite electrode constituents as a key element in ensuring electrode stability. Recently, a poly[3-(potassium-4-butanoate)thiophene] (PPBT) binder component, coupled with a polyethylene glycol (PEG) surface coating for the active material was demonstrated to enhance both electron and ion transport in magnetite-based anodes, and it was established that the PEG/PPBT approach aids in overall battery electrode performance. Herein, the PEG/PPBT system is used as a model polymeric binder for understanding cation effects in anode systems. As such, the potassium ion was replaced with sodium, lithium, hydrogen, and ammonium through ion exchange. The potassium salt exhibited the most stable electrochemical performance, which is attributed to the cation size and resultant electrode morphology that facilitates ion transport. The lithium analogue demonstrated an initial increase in capacity but was unable to maintain this performance over 100 cycles; while the sodium-based system exhibited initially lower capacity as a result of slow reaction kinetics, which increased as cycling progressed. The parent carboxylic acid polymer and its ammonium salt were notably inferior. The results exploring the effect of ion exchange creates a framework for understanding how cations associated directly with the polymer impact electrochemical performance and aid in the overall design of binders for composite Li-ion battery anodes.

One of the inherent challenges with Li-S batteries is polysulfide dissolution, in which soluble polysulfide species can contribute to the active material loss from the cathode and undergo shuttling reactions inhibiting the ability to effectively charge the battery. Prior theoretical studies have proposed the possible benefit of defective 2 D MoS

Developing scalable energy storage systems with high energy and power densities is essential to meeting the ever-growing portable electronics and electric vehicle markets, which calls for development of thick electrode designs to improve the active material loading and greatly enhance the overall energy density. However, rate capabilities in lithium-ion batteries usually fall off rapidly with increasing electrode thickness due to hindered ionic transport kinetics, which is especially the issue for conversion-based electroactive materials. To alleviate the transport constrains, rational design of three-dimensional porous electrodes with aligned channels is critically needed. Herein, magnetite (Fe

Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a ^{54}Ca beam striking on a liquid hydrogen target at ∼200 MeV/u. A significantly larger cross section to the p_{3/2} state compared to the f_{5/2} state observed in the excitation of ^{53}Ca provides direct evidence for the nature of the N=34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.

Silicon offers high theoretical capacity as a negative electrode material for lithium-ion batteries; however, high irreversible capacity upon initial cycling and poor cycle life have limited commercial adoption. In this work, an operando isothermal microcalorimetry (IMC) study of a model system containing lithium metal and silicon composite film electrodes was reported on the first two cycles of (de)lithiation. The total heat flow data are analyzed in terms of polarization, entropic, and parasitic heat flow contributions to quantify and determine the onset of parasitic reactions. These parasitic reactions, which include solid−electrolyte interphase formation, contribute to electrochemical irreversibility. To complement the calorimetry, operando X-ray diffraction is used to track the phase evolution of silicon. During cycle 1 lithiation, crystalline Si undergoes transformation to amorphous lithiated silicon and ultimately to crystalline Li15Si4. The solid-state amorphization process is correlated to a decrease in entropic heat flow, suggesting that heat associated with the amorphization contributes significantly to the entropic heat flow term. This study effectively uses IMC to probe the parasitic reactions that occur during lithiation of a silicon electrode, demonstrating an approach that can be broadly applied to quantify parasitic reactions in other complex systems.