Designing environmentally responsible components for lithium-ion batteries (LIBs) requires a deeper understanding of how binder materials interact at the most fundamental level. In this study, we perform first-principles investigation that focuses exclusively on monomer-level interactions between a C2BN monolayer and key synthetic and bio-based binder precursors. Four synthetic monomers like vinylidene fluoride (VDF), pyrrole (PY), tetrafluoroethylene (TFE) and acrylonitrile (ACN) are examined along with three lignin-derived units which are coumaryl alcohol (LCmA), coniferyl alcohol (LCnA) and sinapyl alcohol (LSiA). Our findings reveal the structural, dynamical, thermal, mechanical and electronic characteristics of the pristine C2BN monolayer. Among the bio-based monomers, LSiA exhibits the strongest adhesion (-44.69 kcal/mol) due to its methoxy-substituted aromatic structure. To understand how these monomers may influence electrode behaviour, the study also evaluates Li-ion adsorption and diffusion characteristics in the presence of monomer-adsorbed C2BN surfaces. Additionally, the interaction of the pristine C2BN monolayer with carbonate-and ether-based electrolytes is analysed to assess interfacial stability. Overall, this work provides a computational basis for how individual binder monomers interact with C2BN electrode surfaces, offering valuable insight for the rational development of sustainable binder systems for future LIB applications.

Binary metal oxide nanoparticles (biMO-NPs) combining transition and main-group metals with well-organized atomic architectures have unique potential as robust and economical heterogeneous catalysts. Herein, metal oxide nanoparticles (CoAlxOy) using cobalt and aluminum were synthesized, and their structure, morphology, and chemical composition were investigated using various characterization techniques. The biMO-NPs, which had a Gaussian-type size distribution (∼6 nm), were assembled on plain silicon substrates modified chemically with linker molecules bearing suitable end groups. Surface analysis revealed an ordered, uniform, close-packed arrangement of biMO-NPs forming a monolayer architecture with nanoscale thickness (∼12 nm), high surface uniformity, and negligible defects. The nanoparticle monolayer film (NP-MF) was employed as a catalyst to grow carbon nanotube (CNT) forests via the thermal chemical vapor deposition (CVD) method, similar to those grown from catalyst thin films deposited by physical vapor deposition. Structural characterization confirmed the growth of a dense, uniform, high-quality vertically aligned carbon nanotube (VA-CNT) forest with a length of ∼125 µm, which is comparable to the VA-CNTs grown from expensive thin films. Thus, CNT growth was successfully catalyzed by the biMO-NPs, highlighting a simple and inexpensive alternative for catalyst deposition. In this innovative wet-chemistry approach, the catalyst and catalyst support are combined within a single nanoparticle before NP-MF assembly. Interestingly, this approach provides a scalable and cost-effective pathway for CNT growth, eliminating the need for expensive thin deposition techniques.

Sulfide-type sodium (Na) solid electrolytes (SEs) with halide doping have attracted serious interest due to their high ionic conductivity and great potential in solid-state Na batteries. While other halogens such as Cl, Br, I have been studied to enhance Na-ion transport in sulfide-type SEs, the introduction of fluorine (F) is rarely investigated. Moreover, synthetic parameters such as heating treatment temperatures strongly influence the structure and conductive properties of halide-doped sulfide SEs. Herein, we prepared xNaF(1-x)Na3SbS4 nanocomposites with varying concentration of F using a low-temperature (150 degrees C) heating method, and studied the effects of post-heating treatment on structure and conductivity. In-situ neutron diffraction was employed to investigate the structural evolution of X-doped Na3SbS4 (X = F, Cl) during the post-heating treatment and cooling process. In addition, the post-heating treatment at 300 degrees C leads to increased ionic conductivity of xNaF(1-x)Na3SbS4 nanocomposites with various F contents. After 300 degrees C post-heating treatment, 0.2NaF0.8Na(3)SbS(4) exhibited the highest conductivity of 0.48 mS cm(-1) at room temperature. Moreover, improved electrochemical stability was also observed in Na-Sn symmetric cells, specially, with prolonged stable cycling for 300 h and much lower polarization voltage (<0.35 V). This work highlights the importance of post-heating treatment on the structural evolution and its role in exploring new halide-incorporated sulfide-type SEs, promoting the development of inorganic solid-state ionic conductors.

Energy-efficient and low-temperature iron electrolysis in alkaline solutions is a low-cost and sustainable ironmaking process with zero-carbon emissions when renewable electrical sources are involved. However, its implementation is hindered by electrochemically inert Fe3O4 and parasitic H2 gas formation during the electrochemical reduction process, resulting in the low energy efficiency of iron electrolysis. Here, we further explore the potential of electrochemical reduction of goethite (FeOOH) by employing a low concentration of silicate additive in an alkaline solution to mitigate Fe3O4 accumulation and H2 generation. Electrochemical measurements coupled with operando X-ray diffraction and X-ray absorption spectroscopy suggested FeOOH → Fe3O4 → Fe-(OH)2 → Fe reduction pathways. Interestingly, a poorly crystalline or amorphous Fe-(OH)2 phase formed in the NaOH/silicate mixed electrolyte, possibly due to the inhibitive effect of silicate on water and ion transport, which eventually contributed to the improved reduction of Fe3O4, also supported by atomistic simulations. This work demonstrates the potential for silicate as a low-cost and effective electrolyte additive to improve room-temperature green iron formation via electrolysis.

We present a systematic angle-resolved polarized Raman spectroscopy (ARPRS) study of black phosphorus (BP) nanostructures formed via electrochemical sodium-and lithium-ion intercalation. Sodium intercalation leads to bundles of densely packed, highly uniform phosphorene nanoribbons (PNRs) separated by parallel amorphous channels, whereas lithium intercalation results in shorter, irregular nanoribbon-like segments with lower aspect ratios. In both cases, six additional Raman peaks (P1-P6) appear alongside the three primary Raman-active modes of BP (A1g, B2g, and A2g). These peaks are attributed to the amorphous regions, as confirmed by their isotropic angular dependence in ARPRS measurements. The three BP modes show pronounced angular variations that differ significantly between the two intercalated samples. In sodium-intercalated BP, A1g and A2g modes retain a dumbbell-like angular dependence under parallel polarization with enhanced anisotropy and reduced symmetry under crossed polarization. At the same time, the B2g mode transitions from four-lobed (cloverleaf) polar plot to a butterfly-like one. In contrast, lithium-intercalated BP exhibits weaker anisotropy and less anisotropic features in the angular polar plots for all three modes. These differences reflect the sensitivity of phonon behavior to underlying nanostructure morphology. The vibrational frequencies density of states (FDOS) calculations attribute the B2g mode change to phonon band folding and mode mixing in PNRs. This study demonstrates the power of ARPRS in probing phonon-structure relationships and highlights the influence of edge geometry and quantum confinement on phonon dispersion in PNRs.

Controlled introduction of oxygen vacancies offers an effective route to induce metal-to-insulator transition in strongly correlated rare-earth nickelates (RNiO_3) at room temperature. However, the role played by the rare-earth cations on the structure, thermodynamic stability, and electronic properties of oxygen-deficient nickelates remains unclear. Here, we employ density functional theory calculations with Hubbard corrections (DFT + U) to investigate the whole family of RNiO_2.5 (R = Pr-Er) compounds in two commonly observed oxygen-vacancy ordered configurations, namely brownmillerite, and square planar. We find that square planar polymorph is always more stable (∼0.4 eV/u.f) than the brownmillerite for all rare-earth cations, owing to the exceedingly low volumetric strains (< 1%). Formation energy of RNiO_2.5 gradually increases with decreasing size of R owing to stronger Ni-O covalent interactions in pristine RNiO_3 with small R^3+ cations. This necessitates more oxygen-lean environments for synthesis of RNiO_2.5 with smaller R^3+ cations. Analysis of the density of states and band structures reveals that electronic structure of RNiO_2.5 is governed by two factors: (a) localization of electron on NiO_6 octahedra yielding a Mott insulating state with strong correlations as Ni e_g is half filled, and (b) crystal field splitting in the NiO_4 tetrahedra/square planar polyhedra. Brownmillerite RNiO_2.5 is metallic, while square planar RNiO_2.5 is an insulator with a predicted gap of ∼ 0.2-0.3 eV, depending on the R^3+ cation. Crystal orbital Hamilton population (COHP) analysis indicates that the Ni-O bond belonging to square-planar NiO_4 polyhedra exhibit much greater covalent character than those in NiO_6 octahedra in square planar RNiO_2.5.

Solid-state sodium (Na) batteries(SSSBs) using sulfide-based solid electrolytes (SEs) has been attracting a lot of attention due to their high theoretical specific capacity, enhanced safety, and abundant resources. Especially, Na3SbS4 shows tremendous potential as a SE owing to its good Na+ ion conductivity of ~1 – 3 mS cm-1. Despite its promise, electrochemical performance of SSSBs based on Na3SbS4 SE remain far from commercialization. The major roadblock thwarting progress in SSSBs is the lack of fundamental understanding of atomic-scale mechanisms underlying (a) interfacial reactions with Na anode, and (b) Na+ ion conduction (especially in the presence of dopants). Here, we employ ab initio molecular dynamics (AIMD) simulations to identify key reactions occurring at the Na|Na3SbS4 interface. Our AIMD simulations indicate that addition of an ionic liquid interlayer results in a stable solid-electrolyte-interphase (SEI) composed mainly of NaF, in excellent agreement with our synthesis and characterization experiments. Similarly, our DFT studies show that Se doping increases the electrochemical stability window of Na3SbS4. In terms of Na+ conduction, we employ AIMD simulations, and nudged elastic band calculations to understand the effect of (a) valence, and (b) size of cation dopants that partially replace Na in Na3SbS4. These cations introduce charge compensating Na-vacancies in the SSE, which in turn, enhance Na+ ion conduction. However, size of the cation dopant has a profound impact on the extent of increase in Na+ ion conductivity. For instance, Ca-doped Na3SbS4 (Na2.75Ca0.125SbS4) showed Na+ conductivity of ~10 times that of pristine Na3SbS4 (rCa2+ / rNa+ = 0.98). On the other hand, larger Ba2+ as dopant (rBa2+ / rNa+ = 1.35) in Na2.75Ba0.125SbS4 hinders Na-ion hops owing to local strain, thereby, yielding a Na+ conductivity ~5 times that of Na3SbS4.We will discuss these findings in the context of developing solid-state electrolytes for emerging SSSBs.

Solid-state lithium-sulfur batteries (SSLSBs) hold great potential as a safe and energy-dense storage technology for wide variety of applications. Among solid-state electrolytes, halogen-doped lithium argyrodites have become an attractive category. This is attributed to their notable features, including high lithium-ion conductivity (~10 -3 S/cm), favorable elastic stiffness (~ 30 GPa), and low flammability, making them promising candidates for enhancing the performance of SSLSBs.Despite their potential, SSLSBs based on sulfide faces challenges due to a limited atomic-scale understanding of ion-conduction, charge transport, structural evolution, and interfacial reactions such as dendrite growth, electrolyte decomposition. Here we employ a combination of density functional theory calculations, and ab initio molecular dynamics simulations to address this challenge for fluorinated argyrodites. Specifically, using accurate materials modeling, we design fluorine-containing argyrodite electrolytes that simultaneously offer enhanced (a) Li-ion conduction facilitated by unique Li-disorder induced by fluorine and other halogen co-dopants, and (b) stability against Li-anode owing to formation of a stable solid-electrolyte interface containing conductive species (Li 3 P), alongside LiCl and LiF. We will discuss these results in the context of accelerating design of novel solid-state electrolytes for long-lived, stable, and high-energy density SSLSBs.

All solid-state lithium-metal batteries (ASSLMBs) using sulfide electrolytes offer tremendous promise due to their increased safety and high theoretical specific capacity. Lithium argyrodites have emerged as a lucrative class of solid-state electrolytes (SSEs) for ASSMLBs, owing to their high Li-ion conductivity (~10-4–10-3 S/cm), good elastic stiffness (~30 GPa), and low flammability. The Li-ion conduction pathways in single-crystalline compounds are typically examined using ab initio molecular dynamics (AIMD) simulations. However, the real-world materials have an added complexity of accounting for grain boundaries (GBs), which makes the AIMD simulations computationally expensive. To circumvent this limitation, we developed a novel ReaxFF interatomic potential, an empirical bond-order based force field, to investigate the effect of GBs on the Li-ion conductivity in argyrodite electrolytes. To carry out the fitting procedure, we used the fundamental static properties such as lattice parameters, heats of formation, elastic constants, surface energies, and equation of states in order to find the best set of ReaxFF parameters for LiPS system. All the static properties used in the fitting process were calculated using the periodic density functional theory. ReaxFF produced lithium diffusion maps of Li7PS6-LT and Li7PS6-HT clearly reproduces the formation of lithium diffusive cages around the sulfur atoms which validates the accuracy of the ReaxFF potential. At the atomic scale, we characterized the energetics, composition, and transport properties of three low-energy (Σ3 and Σ5) symmetric tilt GBs in lithium argyrodites. Our findings indicate that the presence of GBs impede the diffusion of Li ions. The activation energies for Li-ion conduction crossing the grain boundaries are consistently higher than that of the bulk crystal which confirms the significant grain boundary resistance in this material. We also formulate a polycrystalline model to quantify the atomistic effects of the grain boundaries. In this talk, we have explored these results to critically understand the role of grain boundaries on Li conductivity, and how altering the microstructure can be utilized to optimize new high-performance SSEs for emerging ASSLMBs.

Alkaline iron (Fe) batteries are attractive due to the high abundance, low cost, and multiple valent states of Fe but show limited columbic efficiency and storage capacity when forming electrochemically inert Fe3O4 on discharging and parasitic H2 on charging. Herein, sodium silicate is found to promote Fe(OH)2/FeOOH against Fe(OH)2/Fe3O4 conversions. Electrochemical experiments, operando X-ray characterization, and atomistic simulations reveal that improved Fe(OH)2/FeOOH conversion originates from (i) strong interaction between sodium silicate and iron oxide and (ii) silicate-induced strengthening of hydrogen-bond networks in electrolytes that inhibits water transport. Furthermore, the silicate additive suppresses hydrogen evolution by impairing energetics of water dissociation and hydroxyl de-sorption on iron surfaces. This new silicate-assisted redox chemistry mitigates H2 and Fe3O4 formation, improving storage capacity (199 mAh g-1 in half-cells) and coulombic efficiency (94 % after 400 full-cell cycles), paving a path to realizing green battery systems built from earth-abundant materials.

We introduce a quasi-solid-state electrolyte lithium-sulfur (Li–S) battery (QSSEB) based on a novel Li-argyrodite solid-state electrolyte (SSE), Super P–Sulfur cathode, and Li-anode. The cathode was prepared using a water-based carboxymethyl cellulose (CMC) solution and styrene butadiene rubber (SBR) as the binder while Li6PS5F0.5Cl0.5 SSE was synthesized using a solvent-based process, via the introduction of LiF into the argyrodite crystal structure, which enhances both the ionic conductivity and interface-stabilizing properties of the SSE. Ionic liquids (IL) were prepared using lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI) as the salt, with pre-mixed pyrrolidinium bis(trifluoromethyl sulfonyl)imide (PYR) as solvent and 1,3-dioxolane (DOL) as diluent, and they were used to wet the SSE–electrode interfaces. The effect of IL dilution, the co-solvent amount, the LiTFSI concentration, the C rate at which the batteries are tested and the effect of the introduction of SSE in the cathode, were systematically studied and optimized to develop a QSSEB with higher capacity retention and cyclability. Interfacial reactions occurring at the cathode–SSE interface during cycling were also investigated using electrochemical impedance spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy supported by ab initio molecular dynamics simulations. This work offers a new insight into the intimate interfacial contacts between the SSE and carbon–sulfur cathodes, which are critical for improving the electrochemical performance of quasi-solid-state lithium–sulfur batteries.

The ever-growing demand for storing electrical energy generated from intermittent source of renewable energy (e.g., sun, wind etc.) has necessitated development of new low-cost, safe, and sustainable battery systems that go beyond the conventional Li-ion technology. In this context, electrochemistry based on aluminum and iron – third and fourth most abundant elements on earth, respectively – offer the most promise. Unfortunately, long-standing issues with electrolyte design, cyclability, dendrite proliferation, and parasitic side-reactions has precluded deployment of rechargeable Al- or Fe- batteries. Most of the daunting issues stalling progress stem from dearth of atomic-scale understanding of solvation chemistry, ion-transport, chemical reactions, and material evolution in the bulk electrolyte, as well as electrode/electrolyte interfaces. In this talk, I will demonstrate how a synergistic integration of first-principles calculations, ab initio /classical reactive molecular dynamics simulations, electrochemical experiments, and spectroscopic measurements can pave the path towards advancing such understanding; and accelerate design of low-cost battery technologies. Specifically, I will showcase two recent successes of this approach, which led to (a) design of low-cost, fire-resistant inorganic molten-salt electrolytes containing Al n Cl 3n+1 – species, which allow fast de-solvation of Al 3+ ions and prevent dendrite formation – both central for fast-charging Al-chalcogen batteries (200 C) with high cycle life, and (b) demonstration of a novel bi-directional Fe(OH) 2 /FeOOH redox chemistry facilitated by sulfate intercalation in Fe(OH) 2 , which drastically impairs parasitic hydrogen evolution, and Fe 3 O 4 formation – consequently, enhancing capacity and cycle life of alkaline batteries. I will discuss these results in the context of accelerating design of new sustainable high-performance battery technologies for grid-storage.

Sodium chalcogenide ionic conductors are attractive candidates as solid electrolytes (SEs) in solid-state Na metal batteries. They show the advantages of high ionic conductivity of 10-4-10- 2 S cm- 1 at room temperature and great chemical stability in air. However, simple and efficient approaches for the scalable synthesis of chalco-genide solid electrolytes (SEs) are required. In this work, we report a solvent-free mixing to form dry interme-diate products, which are subjected to different treatments (electron-beam assisted method or low temperature heating (& LE;150 degrees C)) to produce pure phase of Na3SbS4-ySey (0 & LE; y & LE; 2) chalcogenides. Heavy Se-doping in Na3SbS4 results in the tetragonal-to -cubic phase transition as well as a significant change of Sb-S bonding in Raman spectra. Among all chalcogenide SEs, Na3SbS3Se showed the highest ionic conductivity of 3.75 x 10-4 S cm-1 at room temperature, 47% higher than that of pristine Na3SbS4. Moreover, the Se-dopant also enhanced the electrochemical stability towards Na metal in solid-state batteries. The solid-state Na||FeS2 battery with Na3SbS3Se SE displayed long-term cycling ability up to 1,000 cycles within the voltage window of 1.0-2.7 V and retained a specific discharge capacity of 105 mAh g-1 after 600 cycles. This technique promotes the practical applications of chalcogenide SEs in solid-state Na batteries.

Sulfide-type argyrodite solid electrolytes (SEs) with halide doping have attracted serious interests. While other halides (Cl, Br) have been found to enhance Li-ion transport in argyrodites, the direct synthesis and without post-processing to produce highly conductive Li6PS5I has been rarely investigated. In this work, we report the direct synthesis of highly conductive Li6PS5I with an impressive ionic conductivity of 2.5 × 10-4 S cm-1 at room temperature through a solvent-based method. Moreover, by introducing F- to partially replace I-, hybrid-doped argyrodites Li6PS5FxI1-x (x = 0.25, 0.5, and 0.75) have been synthesized, and Li6PS5F0.25I0.75 achieves the highest conductivity of 3.5 x 10-4 S cm-1 due to F- and I- dual dopants facilitate faster Li-transport as indicated by density functional theory (DFT) calculations. With higher F-content in argyrodites, Li6PS5F0.75I0.25 displays the best electrochemical stability towards Li metal, as evidenced by long-term stable cycling in Li symmetric cells up to 1,100 hours. Solid-state Li metal batteries with active cathode of Li4Ti5O12 (LTO) display an initial specific capacity of 140 mAh g-1 and remains at 105 mAh g-1 after 200 cycles, suggesting great battery cycling performance. This research expands new compositions in argyrodite SE family and promotes the development of solid-state Li metal batteries.

Linkage isomers are coordination compounds with the same composition but different donor atoms, resulting in distinct physical and electronic structures. A pair of linkage isomers, CuL555 and CuL465, derived from phenylglyoxal bis(ethylthiocarbamate) were synthesized, isolated, and characterized by structural, electrochemical, and spectroscopic methods. The isomers are stable in solution under ambient conditions, but CuL465 converts to CuL555 in acid, consistent with quantum-chemical calculations. The complexes were screened against a lung adenocarcinoma cell line (A549) and a nonmalignant lung fibroblast cell line (IMR-90) to evaluate the antiproliferation activity. CuL555 and CuL465 possessed EC50 values of 0.113 ± 0.030 and 0.115 ± 0.038 μM for A549 and 1.87 ± 0.29 and 0.77 ± 0.22 μM for IMR-90, respectively.

Understanding of structural and morphological evolution in nanomaterials is critical in tailoring their functionality for applications such as energy conversion and storage. Here, we examine irradiation effects on the morphology and structure of amorphous TiO2 nanotubes in comparison with their crystalline counterpart, anatase TiO2 nanotubes, using high-resolution transmission electron microscopy (TEM), in situ ion irradiation TEM, and molecular dynamics (MD) simulations. Anatase TiO2 nanotubes exhibit morphological and structural stability under irradiation due to their high concentration of grain boundaries and surfaces as defect sinks. On the other hand, amorphous TiO2 nanotubes undergo irradiation-induced crystallization, with some tubes remaining only partially crystallized. The partially crystalline tubes bend due to internal stresses associated with densification during crystallization as suggested by MD calculations. These results present a novel irradiation-based pathway for potentially tuning structure and morphology of energy storage materials.

Iron hydroxides are desirable alkaline battery electrodes for low cost and environmental beneficence. However, hydrogen evolution on charging and Fe3O4 formation on discharging cause low storage capacity and poor cycling life. We report that green rust (GR) (Fe2+4Fe3+2 (HO-)12SO4), formed via sulfate insertion, promotes Fe(OH)2/FeOOH conversion and shows a discharge capacity of ∼211 mAh g-1 in half-cells and Coulombic efficiency of 93% after 300 cycles in full-cells. Theoretical calculations show that Fe(OH)2/FeOOH conversion is facilitated by intercalated sulfate anions. Classical molecular dynamics simulations reveal that electrolyte alkalinity strongly impacts the energetics of sulfate solvation, and low alkalinity ensures fast transport of sulfate ions. Anion-insertion-assisted Fe(OH)2/FeOOH conversion, also achieved with Cl- ion, paves a pathway toward efficient utilization of Fe-based electrodes for sustainable applications.