Holey Graphene Research Articles

Supercapacitor electrodes based on Ru/RuO2 decorated on N,S-doped few-layer graphene

Innovatively designed flexible and high-performance shape memory polymer supercapacitors are promising next-generation energy storage devices for portable and wearable electronics. Therefore, thermally induced smart shape memory polymer polyurethane was synthesized using polycaprolactone/poly(ethylene glycol)/hexamethylene diisocyanate (PCL/PEG/HDI) in which the incorporation of PEG successfully assisted in lowering the transition temperature. The resulting polymer exhibits a remarkable transition temperature of 50 °C and a shape recovery ratio of 100 % at a strain of 300 %. The smart polymer was coated with a silver paste to ease the electron flow followed by coating with the electrode. Hybrid electrode materials are prepared in two stages. Initially, a few layers of holey-graphene were synthesized, where BET surface area reveals the presence of pores that are tuned by isothermal treatments in O2-atmosphere. Subsequently, active hybrid electrode materials nanostructured Ru/RuO2 decorated N, S-doped few layers of holey graphene were synthesized using hydrothermal methods. Here, nitrogen and sulfur doping in the basal or edge plane served as catalysts and metal coordination sites, facilitating the uniform distribution of ruthenium nanoparticles on the graphene. It is further confirmed by the density function theory (DFT) calculation using the adsorption energy. The optimized hybrid electrode material demonstrates a specific capacitance of 1297 mFcm−2 at a current density of 2 mAcm−2. A flexible-shape memory polymer supercapacitor exhibits a notable device-specific capacitance of 189 mFcm−2 at a current density of 1 mAcm−2, a high energy density of 45 µWhcm−2 at a power density of 0.25 mWcm−2, with 81 % of specific capacitance retention after eight shape programming and recovery cycle. Excellent shape recoverability and robust electrochemical performance make the as-fabricated symmetric supercapacitors a promising candidate for integration in flexible electronic applications.

Interlayer Space Engineering-Induced Pseudocapacitive Zinc-Ion Storage in Holey Graphene Oxide-Bearing Vertically Oriented MoS2 Nano-Wall Array Cathode for Aqueous Rechargeable Zn Metal Batteries.

Transition metal dichalcogenides, particularly MoS2, are acknowledged as a promising cathode material for aqueous rechargeable zinc metal batteries (ARZMBs). Nevertheless, its lack of hydrophilicity, poor electrical conductivity, significant restacking, and restricted interlayer spacing translate into inadequate capacity and rate performance. Herein, the unique porous structure and additional functional groups present in holey graphene oxide (hGO) are taken advantage of to dictate the vertical growth pattern of oxygen-doped MoS2 nanowalls (O-MoS2/NW) over the hGO surface. Compared to conventional graphene oxide (GO), the presence of nano-pores in hGO facilitates the homogeneous dispersion of Mo precursors and provides stronger interaction sites, promoting the uniform vertical alignment of O-MoS2/NW. The synergistic interaction between O-MoS2-NW and hGO translates to enhanced electron conductivity, efficient electrolyte penetration, enhanced interlayer spacing, reduced restacking, and enhanced surface area. As a consequence of precise control of various factors that decide the overall battery performance, a high discharge capacity (227mAhg-1 at 100mAg-1) cathode material with significantly lower charge transfer resistance (66Ω) compared to pristine O-MoS2 (153Ω) is developed. These findings underscore the potential of hGO as a multifunctional platform for nanoengineering high-performance cathode materials for the next generation of efficient and durable ARZMBs.

Fibrous catalyst based on atomic Pd and N-doped holey graphene functionalized cotton fiber for continuous-flow reaction

Continuous-flow catalysis bridges the gap between bench-scale laboratories and production-scale factories and thus should be a green and promising technology for the manufacture of value-added chemicals. Here, we present the construction of a continuous-flow catalytic system by integrating a tubular reactor with novel catalytic fibers, which are comprised of single-atomic Pd (Pd1) and nitrogen-doped holey graphene (NHG) functionalized cotton fibers (CFs). Due to the loosely packed structure, highly exposed dual-active sites (i.e., single-atomic PdN4 sites and activated C sites in the NHG carbocatalyst) of the CF@(Pd1/NHG) catalytic fibers, the corresponding flowing system exhibites remarkably high catalytic performance (activity and durability) and processing rate in organic reactions, including oxidative hydroxylation of phenylboronic acid and reduction of nitroarenes. Typically, the processing rate of the catalytic system toward 4-nitrophenol (a representative nitroarene) reduction can reach up to 2.46 × 10−3 mmol·mg−1·min−1, significantly higher than that of those packing catalysts reported in recent years.

Prototype Alarm Integrating Pulse-Driven Nitrogen Dioxide Sensor Based on Holey Graphene Oxide/In2O3.

NO2 seriously threatens human health and the ecological environment. However, the fabrication of highly sensitive NO2 sensors with rapid response/recovery rates, low detection limits, and ease of integration remains a challenge. Herein, benefiting from the fast carrier transfer and rich active sites, holey graphene oxide (HGO) was adopted to functionalize the In2O3 nanosheet to construct NO2 gas sensors. Characterization and theoretical calculations established the merits of HGO decoration in the NO2 sensing. The optimal sample, 0.5 wt % HGO/In2O3-sheet, exhibited superior sensing properties, resulting in a 1.37-fold improvement in response to 1 ppm of NO2 compared to the GO/In2O3 counterpart. Gas-sensing kinetics analysis revealed its lower activation energy and higher kinetic rate constants. Importantly, pulsed-temperature modulation was employed to decouple the gas adsorption from surface activation processes, achieving an ultrahigh response of 2776 to 1 ppm of NO2 for the 0.5 wt % HGO/In2O3-sheet sensor. Compared to the isothermal mode, this strategy enhanced the response value by 1.6 times, reduced the response/recovery time by 33%/70%, and enabled the detection of NO2 concentrations as low as 1 ppb. Finally, an NO2 monitoring alarm system based on the 0.5 wt % HGO/In2O3-sheet sensor with pulsed-temperature modulation was demonstrated for hazard warnings.

Ultrahigh Pyridinic/Pyrrolic N Enabling N/S Co-Doped Holey Graphene with Accelerated Kinetics for Alkali-Ion Batteries.

Carbonaceous materials hold great promise for K-ion batteries due to their low cost, adjustable interlayer spacing, and high electronic conductivity. Nevertheless, the narrow interlayer spacing significantly restricts their potassium storage ability. Herein, hierarchical N, S co-doped exfoliated holey graphene (NSEHG) with ultrahigh pyridinic/pyrrolic N (90.6at.%) and large interlayer spacing (0.423nm) is prepared through micro-explosion assisted thermal exfoliation of graphene oxide (GO). The underlying mechanism of the micro-explosive exfoliation of GO is revealed. The NSEHG electrode delivers a remarkable reversible capacity (621 mAhg-1 at 0.05 Ag-1), outstanding rate capability (155 mAhg-1 at 10 Ag-1), and robust cyclic stability (0.005% decay per cycle after 4400 cycles at 5 Ag-1), exceeding most of the previously reported graphene anodes in K-ion batteries. In addition, the NSEHG electrode exhibits encouraging performances as anodes for Li-/Na-ion batteries. Furthermore, the assembled activated carbon||NSEHG potassium-ion hybrid capacitor can deliver an impressive energy density of 141 Whkg-1 and stable cycling performance with 96.1% capacitance retention after 4000 cycles at 1 Ag-1. This work can offer helpful fundamental insights into design and scalable fabrication of high-performance graphene anodes for alkali metal ion batteries.

Synergistic effect of holey graphene and CoSe2-NiSe2 heterostructure to enhance fast Na-ion transport

Inspired by the “Barrel principle” and based on the working principle of the “rocking chair”. We propose two shortboards that “bulk diffusion rate” and “ion reaction rate”, which affect the fast charging of sodium ion batteries (SIBs). The holey reduced graphene oxide (HrGO) with abundant nanopores provides longitudinal diffusion channels, enabling rapid Na+ diffusion along this direction, which solves the shortboard of bulk diffusion rate. Additionally, heterojunctions are considered a viable approach for enhancing fast Na+ storage performance by providing more storage sites and accelerating the kinetics of Na+ reaction, which solve the shortboard of ion reaction rate. Herein, we construct HrGO combined with CoSe2-NiSe2 heterojunctions has been rationally fabricated to synergistically enhance the ionic and electronic diffusion kinetics. As expected, the CoSe2-NiSe2/HrGO anode in SIBs shows an excellent fast-charging performance (392.4mAh/g at 15 A/g), surpassing most Co/Ni-based selenide anodes. Additionally, the assembled CoSe2-NiSe2/HrGO||NVP full cell delivers a high specific capacity of 116.1 and 95.4mAh/g at 0.1 and 20C, respectively, coupled with 97.8 % capacity retention rate for 100 cycles. Furthermore, we elucidate the mechanism of Na+ storage and fast transport through electrochemical kinetic analysis, in situ and ex situ characterizations, density functional theory (DFT) calculations, and distribution of relaxation times (DRT). Importantly, this study provides theoretical insights into accelerating rapid Na+ transfer.

Harnessing Holey MXene/Graphene Oxide Heterostructure to Maximize Ion Channels in Lamellar Film for High-Performance Capacitive Deionization.

2D Ti3C2Tx MXene-based film electrodes with metallic conductivity and high pseudo-capacitance are of considerable interest in cutting-edge research of capacitive deionization (CDI). Further advancement in practical use is however impeded by their intrinsic limitations, e.g., tortuous ion diffusion pathway of layered stacking, vulnerable chemical stability, and swelling-prone nature of hydrophilic MXene nanosheet in aqueous environment. Herein, a nanoporous 2D/2D heterostructure strategy is established to leverage both merits of holey MXene (HMX) and holey graphene oxide (HGO) nanosheets, which optimize ion transport shortcuts, alleviate common restacking issues, and improve film's mechanical and chemical stability. In this design, the nanosized in-plane holes in both handpicked building blocks build up ion diffusion shortcuts in the composite laminates to accelerate the transport and storage of ions. As a direct outcome, the HMX/rHGO films exhibit remarkable desalination capacity of 57.91mg g-1 and long-term stability in 500mgL-1 NaCl solution at 1.2V. Moreover, molecular dynamics simulations and ex situ wide angle X-ray scattering jointly demonstrate that the conductive 2D/2D networks and ultra-short ion diffusion channels play critical roles in the ion intercalation/deintercalation process of HMX/rHGO films. The study paves an alternative design concept of freestanding CDI electrodes with superior ion transport efficiency.

Ti─O─C Bonding at 2D Heterointerfaces of 3D Composites for Fast Sodium Ion Storage at High Mass Loading Level.

3D composite electrodes have shown extraordinary promise as high mass loading electrode materials for sodium ion batteries (SIBs). However, they usually show poor rate performance due to the sluggish Na+ kinetics at the heterointerfaces of the composites. Here, a 3D MXene-reduced holey graphene oxide (MXene-RHGO) composite electrode with Ti─O─C bonding at 2D heterointerfaces of MXene and RHGO is developed. Density functional theory (DFT) calculations reveal the built-in electric fields (BIEFs) are enhanced by the formation of bridged interfacial Ti─O─C bonding, that lead to not only faster diffusion of Na+ at the heterointerfaces but also faster adsorption and migration of Na+ on the MXene surfaces. As a result, the 3D composite electrodes show impressive properties for fast Na+ storage. Under high current density of 10mAcm-2, the 3D MXene-RHGO composite electrodes with high mass loading of 10mgcm-2 achieve a strikingly high and stable areal capacity of 3mAhcm-2, which is same as commercial LIBs and greatly exceeds that of most reported SIBs electrode materials. The work shows that rationally designed bonding at the heterointerfaces represents an effective strategy for promoting high mass loading 3D composites electrode materials forward toward practical SIBs applications.

Systematic tuning of optical and electronic properties of holey graphene quantum dots for UV applications

Graphene quantum dots (GQDs) have remarkably demonstrated themselves as an efficient non-toxic material whose optoelectronic characteristics could be suitably tailored by molecular engineering. In present work, the properties of GQDs have been modified by creating pores in between them and then passivating them with H, F, and O atoms particularly finding their applications in the Ultraviolet (UV) region. For these purposes, materials having an emission wavelength in the UVA region are desirable. It has been investigated that these pores significantly altered the bandgap of GQDs which in turn affected their optical properties. Transitions contributing to the highest peaks in absorption and photoluminescence spectra have been identified and their isosurface contour-maps have also been plotted to find out the nature of this transition. Emission-wavelengths of these holey GQDs have been discovered to fall in the desirable UVA range, which is perfectly suitable for their usage in UV A lamps, medical phototherapy.

Remarkably high tensile strength and lattice thermal conductivity in wide band gap oxidized holey graphene C2O nanosheet

Recently, the synthesis of oxidized holey graphene with the chemical formula C2O has been reported (J. Am. Chem. Soc. 2024, 146, 4532). We herein employed a combination of density functional theory (DFT) and machine learning interatomic potential (MLIP) calculations to investigate the electronic, optical, mechanical and thermal properties of the C2O monolayer, and compared our findings with those of its C2N counterpart. Our analysis shows that while the C2N monolayer exhibits delocalized π-conjugation and shows a 2.47 eV direct-gap semiconducting behavior, the C2O counterpart exhibits an indirect gap of 3.47 eV. We found that while the C2N monolayer exhibits strong absorption in the visible spectrum, the initial absorption peaks in the C2O lattice occur at around 5 eV, falling within the UV spectrum. Notably, we found that the C2O nanosheet presents significantly higher tensile strength compared to its C2N counterpart. MLIP-based calculations show that at room temperature, the C2O nanosheet can exhibit remarkably high tensile strength and lattice thermal conductivity of 42 GPa and 129 W/mK, respectively. The combined insights from DFT and MLIP-based results provide a comprehensive understanding of the electronic and optical properties of C2O nanosheets, suggesting them as mechanically robust and highly thermally conductive wide bandgap semiconductors.

Tuning the water interlayer spacer of microwave-synthesized holey graphene films towards high performance supercapacitor application

Abstract Graphene-based electrodes have been extensively investigated for supercapacitor applications. However, their ion diffusion efficiency is often hindered by the graphene restacking phenomenon. Even though holey graphene (hG) is fabricated to address this issue by providing ion transport channels, those channels could still be blocked by densely stacked graphene nanosheets. To tackle this challenge, this research aims at improving the ion diffusion efficiency of microwave-synthesized hG films by tuning the water interlayer spacer towards the improved supercapacitor performance. By controlling the vacuum filtration during graphene-based electrode fabrication, we obtain dry films with dense packing and wet films with sparse packing. The SEM images reveal that 20 times larger interlayer distance is constructed in the wet film compared to that in the dry counterpart. The hG wet film delivers a specific capacitance of 239 F g−1, ∼82% enhancement over the dry film (131 F g−1). By an integrated experimental and computational study, we quantitatively show that the interlayer spacing in combination with the nanoholes in the basal plane dominates the ion diffusion rate in hG-based electrodes. Our study concludes that novel hierarchical structures should be further considered even in hG thin films to fully exploit the superior advantages of graphene-based supercapacitors.

Computational assessment of the use of graphene-based nanosheets as PtII chemotherapeutics delivery systems.

Graphene is the newest form of elemental carbon and it is becoming rapidly a potential candidate in the framework of nano-bio research. Many reports confirm the successful use of graphene-based materials as carriers of anticancer drugs having relatively high loading capacities compared with other nanocarriers. Here, the outcomes of a systematic study of the adsorption behavior of FDA approved PtII drugs cisplatin, oxaliplatin, and carboplatin on surface models of pristine, holey, and nitrogen-doped holey graphene are reported. DFT investigations in water solvent have been carried out considering several initial orientations of the drugs with respect to the surfaces. Adsorption free energies, calculated including basis set superposition error (BSSE) corrections, result to be significantly negative for many of the drug@carrier adducts indicating that tested layers could be used as potential carriers for the delivery of anticancer PtII drugs. The reduced density gradient (RDG) analysis allows to show that many kinds of non-covalent interactions, including canonical H-bond, are responsible for the stabilization of the formed adducts.

Polyaniline nanoarrays grown on holey graphene constructed by frozen interfacial polymerization as binder−free and flexible gel electrode for high−performance supercapacitor

Compared with disordered structures, electrode materials with nanoarray structures can effectively improve the energy storage capacity of supercapacitors. Therefore, the construction of nanoarrays structures is an important research direction. Here, one kind of frozen interfacial polymerization was used to create a polyaniline (PANI) nanoarrays grown on holey graphene (HG). Long polyaniline nanoarrays were constructed with the promotion of ice crystal growth and the abundant pores of the HG. It is demonstrated that the formation of PANI array and hierarchical nanofiber structures is not only conducive to shorten charge transport, but also can effectively alleviate interfacial side reactions. Moreover, benefiting from the abundant active sites and hierarchical porous structure of the HG, highly oriented growth of PANI arrays, efficient charge diffusion and electrolyte infiltration can be achieved. As a result, specific capacitance, reversibility and cycling stability could be significantly improved. Especially, the PANI/HG−10 exhibited the maximum specific capacitance of 793.7 F g−1 at a current density of 1 A g−1. The all−solid−state flexible symmetric supercapacitor assembled by gel electrode possesses the energy density of 32.5 Wh kg–1 at a power density of 326.5 W kg–1, and maintained an excellent cycle retention approaching 90.5 % after 5000 cycles. This work expands the ideas for array structure construction and electrode fabrication.

Ball‐Milling Synthesis of Richly Oxygenated Graphene‐Like Nanoplatelets from used Lithium Ion Batteries and Its Application for High Performance Sodium Ion Battery Anode

AbstractThe exploration of waste graphite from used lithium ion batteries (LIBs) and its derivatives for versatile applications is an efficient route to promote the environmental and eco‐friendly recycling of used LIBs. Sodium ion batteries (SIBs) are alternative candidates to LIBs mainly due to similar electrochemical mechanism of SIBs to LIBs and rich natural resource of Na. Herein, a holey waste graphite (hGw) with well‐defined porous structure is produced by the annealing of lithiated waste graphite (Li/Gw) from used LIBs under a flow gas of H2O and subsequent lithium leaching in DI water. Benefiting from the holey structure of hGw, holey graphene nanoplatelets (hGnw) with ultrahigh‐level edge‐grafted oxygen groups (≈37.8 at%) are synthesized by mechanical balling of hGw. As anode for SIBs, the hGnw present outstanding sodium ion storage properties with high initial Coulombic efficiency of 82.4%, high reversible capacity (e.g., 416.1 mAh g−1 at 0.03 A g−1), excellent rate capability (e.g., 153.3 mAh g−1 at 2 A g−1), and long‐term cycling stability (e.g., 152.7 mAh g−1 after 400 cycles at 1.5 A g−1).

Establishing reaction networks in the 16-electron sulfur reduction reaction.

The sulfur reduction reaction (SRR) plays a central role in high-capacity lithium sulfur (Li-S) batteries. The SRR involves an intricate, 16-electron conversion process featuring multiple lithium polysulfide intermediates and reaction branches1-3. Establishing the complex reaction network is essential for rational tailoring of the SRR for improved Li-S batteries, but represents a daunting challenge4-6. Herein we systematically investigate the electrocatalytic SRR to decipher its network using the nitrogen, sulfur, dual-doped holey graphene framework as a model electrode to understand the role of electrocatalysts in acceleration of conversion kinetics. Combining cyclic voltammetry, in situ Raman spectroscopy and density functional theory calculations, we identify and directly profile the key intermediates (S8, Li2S8, Li2S6, Li2S4 and Li2S) at varying potentials and elucidate their conversion pathways. Li2S4 and Li2S6 were predominantly observed, in which Li2S4 represents the key electrochemical intermediate dictating the overall SRR kinetics. Li2S6, generated (consumed) through a comproportionation (disproportionation) reaction, does not directly participate in electrochemical reactions but significantly contributes to the polysulfide shuttling process. We found that the nitrogen, sulfur dual-doped holey graphene framework catalyst could help accelerate polysulfide conversion kinetics, leading to faster depletion of soluble lithium polysulfides at higher potential and hence mitigating the polysulfide shuttling effect and boosting output potential. These results highlight the electrocatalytic approach as a promising strategy for tackling the fundamental challenges regarding Li-S batteries.

Minimizing ion/electron pathways through ultrathin conformal holey graphene encapsulation in Li- and Mn-rich layered oxide cathodes for high-performance lithium-ion batteries

PEI/holey graphene encapsulation applied thinly and uniformly to LMR cathode surfaces enhances electrical conductivity, facilitates lithium-ion diffusion, and acts as a protective layer, demonstrating excellent electrochemical performance.

Unravelling the formation of carbyne nanocrystals from graphene nanoconstrictions through the hydrothermal treatment of agro-industrial waste molasses.

The delicate synthesis of one-dimensional (1D) carbon nanostructures from two-dimensional (2D) graphene moiré layers holds tremendous interest in materials science owing to its unique physiochemical properties exhibited during the formation of hybrid configurations with sp-sp2 hybridization. However, the controlled synthesis of such hybrid sp-sp2 configurations remains highly challenging. Therefore, we employed a simple hydrothermal technique using agro-industrial waste as the carbon source to synthesize 1D carbyne nanocrystals from the nanoconstricted zones of 2D graphene moiré layers. By employing suite of characterization techniques, we delineated the mechanism of carbyne nanocrystal formation, wherein the origin of carbyne nanochains was deciphered from graphene intermediates due to the presence of a hydrothermally cut nanoconstriction regime engendered over well-oriented graphene moiré patterns. The autogenous hydrothermal pressurization of agro-industrial waste under controlled conditions led to the generation of epoxy-rich graphene intermediates, which concomitantly gave rise to carbyne nanocrystal formation in oriented moiré layers with nanogaps. The unique growth of carbyne nanocrystals over a few layers of holey graphene exhibits excellent paramagnetic properties, the predominant localization of electrons and interfacial polarization effects. Further, we extended the application of the as-synthesized carbyne product (Cp) for real-time electrochemical-based toxic metal (As3+) sensing in groundwater samples (from riverbanks), which depicted superior sensitivity (0.22 mA μM-1) even at extremely lower concentrations (0.0001 μM), corroborating the impedance spectroscopy analysis.

Carbon quantum dot-assisted VO2(D) welding on holey graphene for zinc-ion battery cathode materials

Superior-quality zinc-ion batteries utilizing nanopseudocapacitor materials and flexible, three-dimensional, highly conductive porous carbon materials are current research hotspots. But the inadequate dispersion between the system components and the dissolution of the pseudocapacitive materials severely limit the further application of VO2-watery zinc-ion battery components (ZIBs). In this work, we create a novel type of independent VO2(D) covered with carbon quantum dots and assist in its welding on holey graphene (CVH). Composite structures of graphene-supported VO2(D) were designed by a simple solvothermal reaction and ultrasonic self-assembly. The CQD coating acts as a conductive medium, facilitating charge transfer to the surface and also mechanically stabilizing the cathode during volume changes, while the CQD acts as a “bridge” to form an intimate interfacial relationship with the HG. The introduction of HG not only provides more sites of activity and longitudinal transport pathways for electron and ion diffusion, but also makes the overall structure more stable and effective in eliminating the effect of volume change and realizing large pseudocapacitance. The electrochemical results show that CVH has an ultra-strong specific capacity of 443 mA h g−1 at 0.1 A/g, and a capacity retention of 332 mAh g−1 after 1000 cycles at 0.5 A/g. Excellent electrochemical performance for Zn2+ ion storage is found in CVH. This unusual structure may help us understand developing ZIB cathodes better while also offering fresh perspectives on high-performance batteries.

Ex-Situ Studies of Hydraulic Pressure Effect on the Electrochemical, Structural and Morphological Properties of Nickel-Rich NMC

The development of industry and technology, as well as the Earth's growing population, is forcing an ever-increasing demand for energy and raw materials. In tandem with this demand, efficient energy storage is also necessary and equally important. One of the most attractive forms of energy storage, has proven to be electrochemical cells, which allow the conversion of chemical reaction energy into electricity. The most promising cell type turned out to be lithium-ion batteries, and this was due to the attractive properties of lithium, which have the high negative standard potential (about -3 V) and high specific capacity (3860 Ah kg-1) 1. The majority of commercial lithium-ion batteries (LIB) are manufactured using roll-to-roll (R2R) wet processing technology (i.e., the slurry method), where active battery powder, conductive carbon powder and inactive binding agent are mixed in a organic solvent , cast onto metallic current collectors and then dried 2. Up next, the electrode layers undergo a calendaring process in which they are compressed. It is important to clarify the effect of hydraulic pressure on the properties of electrode materials and correlate this relationship to its type and characteristics. An inadequate selection of hydraulic pressure conditions can adversely affect the properties of the active battery material, leading to grain cracking and thus the capacity drop. The phenomenon of cracking of nickel-rich NMC secondary particles is considered to be the one of the critical causes that deteriorate the long-term cyclic stability of the NMC cathode in lithium-ion batteries 2,3.In this study various methods are applied to observe and understand the electrode properties that accompany grain fracture and electrode preparation conditions. Morphological changes that occur before and after the electrode calendaring and further the cell’s operation can be examined by scanning electron microscopy (SEM). This technique can be used as a tool to gather information about the composition of cathode materials while tracking a realistically operating battery 3. Another analysis technique is the ex-situ Raman spectroscopy, which allows us to gather detailed information on the local properties of the electrode material. It provides details on phase transitions and the causes of capacity loss over successive battery cycles 4. The information about grain size, crystallographic parameters and the phases present in the sample, can be gathered by X-ray diffraction (XRD). In this research all these methods will be employed to identify possible defects present in electrode materials before and after cycling with regard to applied hydraulic pressure during electrode preparation. We will determine the most suitable hydraulic pressure conditions and correlate our results with initial material morphology and crystallographic structure as well as the electrochemical response. A detailed data analysis will be reported at the conference. Funding for this work was provided by the National Science Center in Poland under the Sonata BIS 11 program (No. UMO-2021/42/E/ST5/00390). A. Czerwiński. Akumulatory, baterie, ogniwa. (2005). Kirsch, D. J. et al. Scalable Dry Processing of Binder-Free Lithium-Ion Battery Electrodes Enabled by Holey Graphene. ACS Appl Energy Mater 2, 2990–2997 (2019). Cheng, X. et al. Real-Time Observation of Chemomechanical Breakdown in a Layered Nickel-Rich Oxide Cathode Realized by in Situ Scanning Electron Microscopy. ACS Energy Lett 6, 1703–1710 (2021). Flores, E., Novák, P. & Berg, E. J. In situ and Operando Raman spectroscopy of layered transition metal oxides for Li-ion battery cathodes. Front Energy Res 6, (2018).

Pd nanoparticles decorated N-doped holey graphene assembled on aluminum silicate fibers agglomerate for catalytic continuous-flow reduction of nitroarenes

Rational design and preparation of efficient fixed-bed catalysts for continuous-flow system are highly desired but remain daunting challenges. Herein, we report the synthesis of an assembly catalyst consisted of aluminium silicate fibers (ASFs) agglomerate and Pd nanoparticles (PdNP) decorated N-doped holey graphene (NHG) through a facile hydrothermal co-assembling strategy. Due to the interconnect network and porous structure, the as-obtained PdNP/NHG-ASFs assembly is suitable to be utilized as a fixed-bed catalyst for organic reactions in continuous-flow mode. The processing rate is much higher than that of the previously reported fixed-bed systems based on metal-based catalysts. In addition, the catalytic continuous-flow system displays a remarkable durability and good substrate generality to other substituted nitrobenzenes. This work provides rational design concept for efficient fixed-bed catalyst with dual active components and paves a way for the industrial application in organic synthesis.