Subsequent Intercalation Research Articles

Biomass‐Derived Carbon Materials for Smart Electronics: Insights from Wood Pitch‐based Microsupercapacitors

AbstractWood pitch, derived from dry distillation of wood, is a promising carbon electrode material. A novel strategy is presented for fabricating honeycomb‐like porous carbon nanosheets using a template‐free approach. Wood pitch is pre‐treated with H₂O₂ to introduce oxygen‐containing functional groups selectively at the edges of polycyclic aromatic hydrocarbons, enhancing hydrophilicity and reactivity. Adding rosin groups to the oxidized wood pitch molecules helps to regulate intermolecular spacing and prevent excessive aggregation, facilitating subsequent KOH intercalation activation and the formation of a porous structure. The resulting rosin‐modified wood pitch‐based carbon material (RWPC‐0.2) features a high specific surface area (3521.5 m2 g−1). With a current density of 1 A g−1, the device has a specific capacitance of 376 F g−1. After 5000 cycles at 10 A g−1, it still has 83.8% of its initial specific capacitance. Using direct ink writing (DIW) technology in combination with poly(3,4‐ethylenedioxythiophene): polystyrene sulfonate/RWPC‐0.2 (PEDOT: PSS/RWPC‐0.2) as the electrode ink, microelectrodes are fabricated and microsupercapacitors are constructed with high areal capacitance (460 mF cm−2), excellent rate performance, and good cycling stability. This study offers new insights for developing printed micro‐energy storage devices based on wood pitch‐derived carbon materials and opens new possibilities for the application of biomass materials in smart electronics.

Synergistic effect of oxygen defects and calabash-like hollow carbon matrix enables VO2 as high-performance cathode for zinc ion battery

Vanadium dioxide (VO2) materials exhibit significant theoretical specific capacity, which is ascribed to multi-electron transfer reactions and unique tunneled structures. However, the low electronic conductivity and sluggish reaction kinetics of VO2 have impeded its further development. Hence, in this study, we employed a synergistic strategy of defect engineering and compositing with a calabash carbon matrix to reduce Zn2+ diffusion barriers and accelerate electron transfer. The VO2 cathode provided a high specific capacity at a low rate of 303 mA h g−1 at 0.1 A g−1 after 191 cycles, along with good rate performance (168 mA h g−1 at 10 A g−1) and satisfactory long-term stability (170 mA h g−1 at 1 A g−1 after 1100 cycles). The exhaustive structural analyses indicated that oxygen vacancies accelerated the Zn2+ diffusion rate, while a uniform calabash-like hollow carbon matrix improved electronic conductivity during cycling. Moreover, ex-situ measurements demonstrated that during discharge, the composite cathode transformed to layered Zn3+x(OH)2V2O7·2H2O, which then facilitated the subsequent intercalation of Zn2+. This cooperative strategy advances the practical application of aqueous zinc ion batteries by leveraging vanadium-based electrodes.

Unveiling Intercalation Chemistry via Interference-Free Characterization Toward Advanced Aqueous Zinc/Vanadium Pentoxide Batteries.

Aqueous Zn/V2O5 batteries are featured for high safety, low cost, and environmental compatibility. However, complex electrode components in real batteries impede the fundamental understanding of phase transition processes and intercalation chemistry. Here, model batteries based on V2O5 film electrodes which show similar electrochemical behaviors as the real ones are built. Advanced surface science characterizations of the film electrodes allow to identify intercalation trajectories of Zn2+, H2O, and H+ during V2O5 phase transition processes. Protons serve as the vanguard of intercalated species, facilitating the subsequent intercalation of Zn2+ and H2O. The increase of capacity in the activation process is mainly due to the transition from V2O5 to more active V2O5·nH2O structure caused by the partial irreversible deintercalation of H2O rather than the increase of active sites induced by the grain refinement of electrode materials. Eventually, accumulation of Zn species within the oxide electrode results in the formation of inactive (Zn3(OH)2V2O7·2H2O) structure. The established intercalation chemistry helps to design high-performance electrode materials.

Defect engineering and in-situ electrochemical oxidation promote lattice reconstruction of VO2 for boosting the energy storage of aqueous zinc-ion batteries

Finding a cathode with high capacity and rate performance is very important for the large-scale application of low-cost and safe aqueous zinc-ion batteries (AZIBs). In this work, VO2 containing oxygen rich vacancies (VO) was designed through fine regulation of the hydrothermal reaction, which was mainly due to the escape of crystalline water in the material. The rich oxygen vacancies in VO will adsorb water molecules in electrolyte and have redox reaction with water molecules, thus promoting the in-situ lattice reconstruction process. On the first charge of in-situ electrochemical oxidation process, VO undergoes a complete phase transition to an oxygen-deficient V2O5/V2O5·nH2O (O-VO), allowing subsequent (de)intercalation of zinc cations on the basis of the latter structure. The electrode thus has significant rate performance (376 mAh/g at 20 A/g). The energy density/power density at 20 A/g is 274 Wh kg−1/14550 W kg−1. This work provides fundamental insights into the formation of oxygen vacancies in materials, and for the first time combines defect engineering with in-situ electrochemical oxidation strategies, providing an innovative design strategy for constructing cathodes with high-rate capacity and high energy storage.

Deciphering Anion-Modulated Solvation Structure for Calcium Intercalation into Graphite for Ca-Ion Batteries.

Co-intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated-Ca-ion in dimethylacetamide-based electrolytes and graphite intercalation compounds. Among the anions considered (BH4 -, ClO4 -, TFSI- and [B(hfip)4]-), the coordination of four solvent molecules per Ca ion (CN=4) leads to the highest reversible capacities and the fastest reaction kinetics in graphite. Our study illuminates the origins of the distinct Ca ion intercalation behaviors across various anion-modulated electrolytes, employing a blend of experimental and theoretical approaches. Importantly, the practical viability of graphite anodes in Ca-ion full cells is confirmed, showing significant promise for advanced energy storage systems.

Deciphering Anion‐Modulated Solvation Structure for Calcium Intercalation into Graphite for Ca‐Ion Batteries

AbstractCo‐intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated‐Ca‐ion in dimethylacetamide‐based electrolytes and graphite intercalation compounds. Among the anions considered (BH4−, ClO4−, TFSI− and [B(hfip)4]−), the coordination of four solvent molecules per Ca ion (CN=4) leads to the highest reversible capacities and the fastest reaction kinetics in graphite. Our study illuminates the origins of the distinct Ca ion intercalation behaviors across various anion‐modulated electrolytes, employing a blend of experimental and theoretical approaches. Importantly, the practical viability of graphite anodes in Ca‐ion full cells is confirmed, showing significant promise for advanced energy storage systems.

High-conductivity and elasticity interface consisting of Li-Mg alloy and Li3N on silicon for robust Li-ion storage

Silicon (Si) materials are one of the industry's preferred choices for lithium-ion batteries (LIBs) anode in the near and mid-term due to their high theoretical capacity, abundance in earth and safety. However, the weak and low conductivity of the solid electrolyte interface (SEI) leads to poor cycling stability, limited Coulombic efficiency, and poor rate performance, consequently hampering practical applications. Herein, the MgSiN2 functional coating is prepared by in-situ evolution of Mg2Si on porous micro-Si (pMSi@MgSiN2) via a scalable one-step low-temperature nitriding strategy. Interestingly, MgSiN2 is converted into the robust multi-functional interface composed of highly conductive Li3N and elastic Li-Mg alloy during subsequent lithium intercalation, which is studied by in-situ/ex-situ methods. The multi-functional interface takes over the role of improving interfacial stability and ionic/electronic conductivity. As expected, the pMSi@MgSiN2 anode shows a high gravimetric capacity of 1981.5 mAh g−1 at 1.0 A g−1 after 150 cycles, together with a high initial Coulombic efficiency of over 88.4 %. Furthermore, a consider capacity of 894 mAh g−1 can be retained after 500 cycles at 5.0 A g−1. The results and strategy reveal a new route for the integrated design of Si interface or other alloy-type anode materials to the fast lithium storage performance.

Tailored thymoquinone intercalated Layered Double Hydroxide (LDH) nanocomposites to accelerate mineralization for enhanced osteogenesis

The tunable nature of two-dimensional nanostructured Layered Double Hydroxides [LDH] and their effective intercalation ability with biomolecules make them inevitable functional hybrid materials for versatile biomedical applications. In an attempt to meet the limitations in existing bone reconstruction practice, the present work reports the synthesis of zinc and iron-based LDH [Zn-Fe LDH] and its subsequent intercalation with thymoquinone [TQ-Zn-Fe LDH] to augment osteoblastic differentiation and proliferation for accelerated bone mineralization. Structural studies depicted the polycrystalline and amorphous nature of ZnFe LDH and TQ-Zn-Fe LDH respectively. The biocompatible nature of LDHs was proven by negative cytotoxicity, cell adhesion, and proliferation assays studied in MG-63 cell lines. Gene expression studies of the nanocomposites showed a fold change of 5–10 in osteoblastic differentiation and proliferation. However, TQ-Zn-Fe LDH treated cells showed significantly higher protein translation levels of osteogenesis markers and elevated alkaline phosphatase secretion and calcium deposition on day 21, confirming their osteogenic efficiency. Thus, acquired results speculate the osteogenic potential of thymoquinone intercalated TQ-Zn-Fe-LDH to meet the limitations in bone reconstruction practice.

Defect engineering unveiled: Enhancing potassium storage in expanded graphite anode

Expanded graphite (EG) stands out as a promising material for the negative electrode in potassium-ion batteries. However, its full potential is hindered by the limited diffusion pathway and storage sites for potassium ions, restricting the improvement of its electrochemical performance. To overcome this challenge, defect engineering emerges as a highly effective strategy to enhance the adsorption and reaction kinetics of potassium ions on electrode materials. This study delves into the specific effectiveness of defects in facilitating potassium storage, exploring the impact of defect-rich structures on dynamic processes. Employing ball milling, we introduce surface defects in EG, uncovering unique effects on its electrochemical behavior. These defects exhibit a remarkable ability to adsorb a significant quantity of potassium ions, facilitating the subsequent intercalation of potassium ions into the graphite structure. Consequently, this process leads to a higher potassium voltage. Furthermore, the generation of a diluted stage compound is more pronounced under high voltage conditions, promoting the progression of multiple stage reactions. Consequently, the EG sample post-ball milling demonstrates a notable capacity of 286.2 mAh g-1 at a current density of 25 mA g−1, showcasing an outstanding rate capability that surpasses that of pristine EG. This research not only highlights the efficacy of defect engineering in carbon materials but also provides unique insights into the specific manifestations of defects on dynamic processes, contributing to the advancement of potassium-ion battery technology.

Room Temperature Ferromagnetism in Graphene/SiC(0001) System Intercalated by Fe and Co

The utilization of graphene on silicon carbide (SiC) substrates holds substantial promise for advancements in spintronics and nanoelectronics. Furthermore, incorporating magnetic metals provides an optimal framework for probing fundamental physical phenomena. The approach to developing such systems is in situ intercalation of graphene with magnetic metals. Herein, the electronic structure is analyzed and the magnetic properties of the system are synthesized by the thermal decomposition of 6H‐SiC(0001) surface and subsequent intercalation of graphene with cobalt (Co) and iron (Fe) atoms. X‐ray photoemission spectroscopy and low‐energy electron diffraction are employed to control the synthesis and metal intercalation processes. The morphological characteristics of the synthesized system are studied by means of atomic force microscopy. The findings derived from magneto‐optic Kerr effect measurements reveal a homogeneous ferromagnetic ordering at room temperature. Angle‐resolved photoemission spectroscopy is used to ascertain the impact of intercalation on graphene's electronic structure. The results of this study are essential for the development of graphene‐based spintronics and nanoelectronic devices as well as for fundamental studies in magnetic graphene systems.

Modulating the Stoichiometry and Lithium Content to Boost the Electrochemical Performance of Li2ZnTi3O8 via High Valence Nb5+ Dopants

AbstractA series of anode materials with the general formula of Li2ZnTi3O8 (LZTO) and Li2‐xZnTi3‐xNbxO8 (x = 0.2, 0.4, and 0.5) (LZTNO) are designed. Different amount of high valence Nb5+ dopants not only reduces the content of lithium in LZTO but also alters the intrinsic characteristics of the composites, leading to optimized electrochemical performances. XRD, SEM, TEM, and XPS results suggest that Nb dopants are introduced successfully, but large amount of Nb5+ dopants (x > 0.2) result in the formation of ZnNb2O6 and TiO2. Owing to the small particle size and the improved structural stability, LZTNO‐2 sample exhibits the best electrochemical performance, and it can deliver a charge/discharge capacity of 182.7/181.2 mAh g−1 at 1 A g−1 after 500 cycles, which is much higher than the value of LZTO (100.41/100.41 mAh g−1). The experiments suggest that the introduction of high valence dopants can effectively modulate the stoichiometry and lithium content of the anode materials, making the available vacant sites for subsequent intercalation of lithium obviously extended. Such a strategy is expected to be feasibly applied to other anode materials to enhance their specific capacity and electrochemical performances.

Multifunctional Metal-organic Frameworks Capsules Modulate Reactivity of Lead Iodide toward Efficient Perovskite Solar Cells with Ultraviolet Resistance.

The two-step sequential deposition process is demonstrated as a reliable technology for the fabrication of efficient perovskite solar cells (PVSCs). However, the complete conversion of dense PbI2 to perovskite in planar PVSCs is tough without mesoporous titanium dioxide as support. Herein, multifunctional capsules consisting of zeolitic imidazolate framework-8 (ZIF-8) encapsulant and formamidinium iodide (FAI) are introduced between tin oxide (SnO2 ) and lead iodide (PbI2 ) layer. Intriguingly, the capsule dopant interlayer benefits the formation of porous PbI2 film due to the porous nanostructure of ZIF-8 which is favorable for the subsequent intercalation reaction. Furthermore, the constituent of the perovskite precursor in ZIF-8 pores can convert into the crystal nuclei of perovskite by reacting with PbI2 first, thereby promoting further perovskite crystallization. Significantly, the incorporation of ZIF-8 can enhance the resistance of perovskite against ultraviolet (UV) illumination due to down-conversion effect. Consequently, the modified device achieves a champion power conversion efficiency (PCE) of 24.08% and displays enhanced UV stability, which can sustain 83% of its original PCE under 365nm UV illumination for 300h. Moreover, the unencapsulated device maintains 90% of initial PCE after 1500h storage in dark ambient conditions with a relative humidity range of 50∼70%. This article is protected by copyright. All rights reserved.

Synergistically tailoring the hierarchical channel structure of graphene oxide membrane through co-assembly strategy for high-performance butanol dehydration

A significant boost in permeate flux along with the desirable separation factor remains a challenging issue for graphene oxide (GO) membranes in pervaporation applications. Herein, a facile approach of co-assembling pristine and etched GO nanosheets was proposed to tailor the hierarchical channel structure (involving the slits, defects and interlayer galleries) of GO membrane and achieve remarkable improvements in both the permeate flux and water/butanol separation factor. Pristine GO nanosheets guarantee a defect-free membrane structure, while etched GO (eGO) provides abundant defects/slits for molecular transport, thus reducing molecular diffusion resistance and doubling permeate flux. The introduction of eGO confers a more ordered nanosheet assembly and narrower interlayer spacing, thus strengthening the size-exclusion effect of the interlayer channels towards butanol molecules and realizing a 3-times enhancement in the separation factor. The subsequent intercalation of Congo red (CR) molecules ulteriorly optimizes the interlayer channels and results in the superior water/butanol separation factor of 5705 with the permeate flux of 4.81 kg/(m2h). This work provides a facile and feasible method for constructing high-performance GO-based membranes with great potential for practical butanol dehydration process.

New insights into thermal processes of metal deposits on h-BN/Rh(1 1 1): A comparison of Au and Rh

In this paper the thermal properties of Au and Rh deposits are compared on hexagonal boron nitride (h-BN) “nanomesh” prepared on Rh(111), applying STM, XPS, low energy ion scattering (LEIS), LEED, and DFT. At room temperature, both metals essentially follow Volmer-Weber (3D) growth. Upon subsequent annealing, agglomeration (sintering), intercalation, and desorption are competing surface processes for both metals. For the more reactive Rh, we suggest an additional encapsulation mechanism: between 600 K and 750 K, fragments of decomposed h-BN diffuse locally from the bottom onto the metal clusters covering them partially. STM data indicates that agglomeration of gold nanoparticles proceeds faster compared to rhodium. At higher temperatures (∼1050 K–1100 K), all non-desorbing gold atoms diffuse below h-BN, even for large initial coverages. On the other hand, for larger Rh deposits (≥5 ML), the outermost layer always contains Rh. Accumulation of gold at the interface between h-BN and Rh(111) significantly enhances the thermal stability of h-BN, attributed to the lower reactivity of Au in the decomposition of h-BN compared to Rh(111). At elevated substrate temperatures, intercalation of individual adatoms takes place during deposition, which requires higher temperatures for rhodium due to its slower diffusion and higher probability of nucleation.

Membrane-Specific Binding of 4 nm Lipid Nanoparticles Mediated by an Entropy-Driven Interaction Mechanism.

Lipid nanoparticles (LNPs) are a leading biomimetic drug delivery platform due to their distinctive advantages and highly tunable formulations. A mechanistic understanding of the interaction between LNPs and cell membranes is essential for developing the cell-targeted carriers for precision medicine. Here the interactions between sub 10 nm cationic LNPs (cLNPs; e.g., 4 nm in size) and varying model cell membranes are systematically investigated using molecular dynamics simulations. We find that the membrane-binding behavior of cLNPs is governed by a two-step mechanism that is initiated by direct contact followed by a more crucial lipid exchange (dissociation of cLNP's coating lipids and subsequent flip and intercalation into the membrane). Importantly, our simulations demonstrate that the membrane binding of cLNPs is an entropy-driven process, which thus enables cLNPs to differentiate between membranes having different lipid compositions (e.g., the outer and inner membranes of bacteria vs the red blood cell membranes). Accordingly, the possible strategies to drive the membrane-targeting behaviors of cLNPs, which mainly depend on the entropy change in the complicated entropy-enthalpy competition of the cLNP-membrane interaction process, are investigated. Our work unveils the molecular mechanism underlying the membrane selectivity of cLNPs and provides useful hints to develop cLNPs as membrane-targeting agents for precision medicine.

Boron nitride-graphene in-plane hexagonal heterostructure in oxygen environment

Aiming to improve fabrication protocols for boron nitride and graphene (h-BNG) lateral heterostructures, we studied the growth of h-BNG thin films on platinum and their behavior in an oxygen environment. We employed a surface science approach based on advanced spectroscopy and imaging techniques to investigate the evolution of surface stoichiometry and chemical intermediates at each reaction step. During oxygen exposure at increasing temperatures, we observed progressive and subsequent intercalation of oxygen, and selective etching of graphene accompanied by the oxidation of boron.Additionally, by exploiting the O2 etching selectivity towards graphene at 250 °C and repeating growth cycles, we obtained in-plane h-BNG layers with controllable compositions and vertically stacked h-BN/Gr heterostructures without the use of consecutive transfer procedures. The growth using a single precursor molecule can be beneficial for the development of versatile atomically thin layers for electronic devices.

Interactions and dynamics of cations and interlayer quest molecules in nontronite and nontronite–formamide intercalation

Nontronite is a swelling clay mineral. Between the layers, it contains water and cations. Nontronite can be easily modified by intercalation. This work focuses on characterizing unmodified nontronite and nontronite intercalated with formamide. Thermal measurements, infrared spectroscopy, X–ray diffraction, and dielectric relaxation measurements were made to evaluate the interactions of the guest molecules with the host layers. A startling effect was observed in dielectric experiments: the low–frequency permittivity detected in nontronite was much larger than in the material intercalated with formamide, the molecule with a high dipole moment. To explain this effect, it was assumed that the low–frequency dielectric relaxation was associated with the movement of interlayer ions. Dehydration of nontronite, which is a stage of preparation for intercalation, can probably fix some ions in hexagonal cavities (privileged positions). Subsequent intercalation of nontronite by formamide does not bring back the mobility of ions, and the low–frequency electric permittivity remains relatively low. To achieve mobility of the cations, an expansion of the interlayer space is required, and ion–dipole interactions with guest molecules should be present.

Preparation of Dye Molecule-Intercalated MoO3 Organic/Inorganic Superlattice Nanoparticles for Fluorescence Imaging-Guided Catalytic Therapy.

Intercalation of organic molecules into the van der Waals gaps of layered materials allows for the preparation of organic/inorganic superlattices for varying promising applications. Herein, the preparation of a series of dye molecule/MoO3 organic/inorganic superlattice nanoparticles by aqueous intercalation of several dye molecules into layered MoO3 for fluorescence imaging-guided catalytic therapy is reported. The long MoO3 nanobelts are treated by ball milling and subsequent aqueous intercalation followed by a cation ion exchange to obtain the dye molecule-intercalated MoO3 organic/inorganic superlattices. Importantly, because of the activation induced by organic intercalation, the Nile blue (NB)-intercalated MoO3-x (NB-MoO3-x ) nanoparticles show excellent catalytic activity for the generation of reactive oxygen species, that is, hydroxyl radical (·OH) and superoxide anion (·O2- ), through catalyzing H2 O2 and O2 , respectively. Moreover, the intense fluorescence of the intercalated NB molecules endows NB-MoO3-x with the in vivo fluorescence imaging capability. Thus, the polyvinylpyrrolidone-modified NB-MoO3-x nanoparticles can be used for tumor-specific catalytic therapy to realize efficient cancer cell elimination in vitro and fluorescence imaging-guided tumor ablation in vivo.

Cascaded and nonlinear DNA assembly amplification for sensitive and aptamer-based detection of kanamycin

Simple, selective and sensitive monitoring of antibiotic residues in food is essential for food safety and human health because of its side effects upon inappropriate usage. Here, with a new label- and enzyme-free significant signal enhancement approach by the coupling of catalytic hairpin assembly (CHA) with nonlinear hybridization chain reaction (nHCR), we developed a fluorescence aptamer sensor for the detection of trace kanamycin in milk samples with high selectivity and sensitivity. The binding of the target kanamycin to the aptamer probe could initiate the CHA between two hairpins for the formation of partial DNA duplexes, which further triggered the nHCR of other three hairpins to yield branched DNA complexes with a multitude of active G-quadruplex structures. The subsequent intercalation of the organic dye, thioflavin T, into G-quadruplex structures resulted in significantly enhanced fluorescence responses for realizing sensitive sensing of kanamycin in the dynamic range of 0.1–300 nM with a detection limit of 46.1 pM. Besides, this strategy could also achieve the monitoring of kanamycin selectively in spiked milk samples. With features of high sensitivity and simplicity in a non-enzyme/label fashion, our signal amplification strategy has high potentials for establishing sensitive and convenient means to monitor various antibiotics.

In Situ Electrochemically Activated Vanadium Oxide Cathode for Advanced Aqueous Zn-Ion Batteries.

The search for large-capacity and high-energy-density cathode materials for aqueous Zn-ion batteries is still challenging. Here, an in situ electrochemical activation strategy to boost the electrochemical activity of a carbon-confined vanadium trioxide (V2O3@C) microsphere cathode is demonstrated. Tunnel-structured V2O3 undergoes a complete phase transition to a layered, amorphous, and oxygen-deficient Zn0.4V2O5-m·nH2O on the first charge, thus allowing subsequent (de)intercalation of zinc cations on the basis of the latter structure, which can be regulated by the amount of H2O in the electrolyte. The electrode thus delivers excellent stability with a significantly high capacity of 602 mAh g-1 over 150 cycles upon being subjected to a low-current-rate cycling, as well as a high-energy density of 439.6 Wh kg-1 and extended life up to 10000 cycles with a 90.3% capacity retention. This strategy will be exceptionally desirable to achieve ultrafast Zn-ion storage with high capacity and energy density.