Silicon Carbon Research Articles

Crack-Resistant Si-C Hybrid Microspheres for High-Performance Lithium-Ion Battery Anodes.

To effectively solve the challenges of rapid capacity decay and electrode crushing of silicon-carbon (Si-C) anodes, it is crucial to carefully optimize the structure of Si-C active materials and enhance their electron/ion transport dynamic in the electrode. Herein, a unique hybrid structure microsphere of Si/C/CNTs/Cu with surface wrinkles is prepared through a simple ultrasonic atomization pyrolysis and calcination method. Low-cost nanoscale Si waste is embedded into the pyrolysis carbon matrix, cleverly combined with the flexible electrical conductivity carbon nanotubes (CNTs) and copper (Cu) particles, enhancing both the crack resistance and transport kinetics of the entire electrode material. Remarkably, as a lithium-ion battery anode, the fabricated Si/C/CNTs/Cu electrode exhibits stable cycling for up to 2300 cycles even at a current of 2.0 A g-1, retaining a capacity of ≈700 mAh g-1, with a retention rate of 100% compared to the cycling started at a current of 2.0 A g-1. Additionally, when paired with an NCM523 cathode, the full cell exhibits a capacity of 135 mAh g-1 after 100 cycles at 1.0C. Therefore, this synthesis strategy provides insights into the design of long-life, practical anode electrode materials with micro/nano-spherical hybrid structures.

One-step fabrication of binder-free nanoSi-CNT-carbon black/cyclized PAN composite anode for high-performance lithium-ion batteries

Silicon is one of the most promising anode materials for lithium-ion batteries (LIBs) due to its high theoretical capacity. However, its non-conductive nature and significant volume expansion during lithiation pose challenges. In this study, we developed a novel electrode comprising silicon nanoparticles (nanoSi), carbon nanotubes (CNTs), and carbon black (CB) in cyclized polyacrylonitrile (cPAN), referred to as nanoSi-CNT-CB/cPAN. This electrode is fabricated through a one-step thermal process by heating a cast nanoSi-CNT-CB/PAN film on Cu foil at 310 °C. The LIB performance using the nanoSi-CNT-CB/cPAN electrode shows an impressive initial coulombic efficiency of 93.1 % at 0.1 A g−1, a high specific capacity of 2267.2 mAh g−1 at 0.5 A g−1, and a retention of 89.2 % over 390 cycles, achieving 783 mAh g−1 at 5 A g−1. We attribute these results to the fused cPAN, which provides good adhesion to nanoSi, CNTs, CB, and Cu foil, acting as a binder, active material, and ionic conductive medium. The well-dispersed CNTs and CB form an effective conductive network in the electrode. Additionally, the one-step electrode fabrication is a simple and cost-effective process for next-generation Si-based LIBs.

Constructing carbon nanotube (CNTs)/silica superhydrophobic coating with multi-stage rough structure for long-term anti-corrosion and low-temperature anti-icing in the marine environment

The rough superhydrophobic surface is beneficial for capturing more gases underwater, which enhances corrosion and ice resistance for marine equipment. In this work, a PVAc-PVDF-FMCS (PPFMCS) multi-stage rough superhydrophobic coating was manufactured by a cold spraying method, significantly improving the anti-corrosion and anti-icing of aluminium alloy. The point-line structure was designed by cross-linking between multi-walled carbon nanotubes (MWCNTs) and silicon dioxide (SiO2), which facilitated the formation of multi-stage rough surface. The porous skeleton and interfacial adhesion of the PPFMCS coating were attributed to the introduction of polyvinylidenefluoride (PVDF) and polyvinylacetate (PVAc), respectively. The PPFMCS coating had good superhydrophobicity with a water contact angle of 163.5°, while exhibiting the outstanding performance of long-term anti-corrosion and anti-icing. The |Z|0.01 Hz value of the PPFMCS coating was still 9.62 × 109 Ω cm2 in 3.5 wt% NaCl solution for 35 days, only two orders of magnitude lower than that of the original coating, the equivalent circuits were further investigated and the metal protection is evaluated on the shore or in the deep ocean of the South China Sea. The PPFMCS coating was able to obviously delay icing for 5 min at −20 °C, the ice adhesion of its surface was as low as 85.5 kPa. The icing phase transition was analysed by a thermodynamic method. The coating also had good stability and drag reduction performance. This high-performance coating based on point-line structural design is expected to have practical applications in marine transportation, oil exploration and polar exploration.

A realistic assessment of the prospect that silicon be replaced by other materials for IC application

Silicon is the most significant material in the semiconductor industry, and the whole semiconductor industry is established on silicon materials. Silicon accounts for about a third of the value of the material used to make the entire wafer. However, with the development of the semiconductor industry and integrated circuit chips, the requirements for semiconductor materials are also increasing. In some application scenarios, silicon is gradually unable to meet peoples higher requirements. For example, in high-frequency applications, the characteristics of silicon may be limited. At higher frequencies, the conductivity of silicon may not be ideal, leading to signal delay and performance loss. Therefore, finding alternative materials for silicon has become one of the current research topics for scientists, in order to solve some problems that silicon cannot solve under specific conditions. In this article, we mainly explore the characteristics and advantages of carbon nanotubes, gallium arsenide, and silicon carbide materials to analyze the feasibility of these materials replacing silicon in the field of integrated circuits.

Ab initio study of helium behavior near stacking faults in 3C-SiC

First-principles calculations are used to investigate the effects of stacking faults (SFs) on helium trapping and diffusion in cubic silicon carbon (3C-SiC). Both extrinsic and intrinsic SFs in 3C-SiC create a hexagonal stacking sequence. The hexagonal structure is found to be a strong sink of a helium interstitial. Compared to perfect 3C-SiC, the energy barriers for helium migration near the SFs increase significantly, leading to predominant helium diffusion between the SFs in two dimensions. This facilitates the migration of helium towards interface traps, as confirmed by previous experimental reports on the nanocrystalline 3C-SiC containing a high density of SFs. This study also reveals that the formation of helium interstitial clusters near the SFs is not energetically favored. The findings from this study enhance our comprehension of helium behavior in faulted 3C-SiC, offering valuable insights for the design of helium-tolerant SiC materials intended for reactor applications.

Preparation and chromatographic evaluation of hydrophilic polymer brushes grafted-silica with post modification of silicon/carbon dots as a green liquid chromatography stationary phase.

Polar stationary phases were prepared by grafting hydrophilic acrylamide (Am) polymer brushes with post modification of carbon dots (CDs) and silicon dots (SiDs) onto SiO2 particles. The prepared stationary phases, SiO2-PAm-CDs, SiO2-PAm-CDs/SiDs, and SiO2-PAm-SiDs, were packed as chromatographic columns, respectively. Using nucleic bases, organic acids, and β-agonists as targetsubstances to investigate the influence of chromatographic conditions on retentionand separation, the packed columns showed the partitioning and adsorption of mixed retention behavior in hydrophilic interaction liquid chromatography mode and successfully separated thepolar compounds. Most importantly, under per aqueous liquid chromatography mode (using 100% water as mobile phase), those columns still had goodseparation ability toward nucleic bases, β-agonist, and organic acids. Because AM isa temperature-sensitive monomer, the resulting van't Hoff curves exhibited a nonlinear relationship, having temperature-responsive chromatographic characteristic under pure water separation. Hence, building on temperature-sensitive characteristics and pure water of separation conditions, the separation selectivity toward hydrophilic compounds greatly improved. Compared with the commercial hydrophilic columns, the efficiency of our developed column had the superior ability in separation and detection of betaine in Goji berry with the enhanced resolution achieved in the proposedgreen separation method(just using pure water as mobile phase).

Poly(ethylene) Oxide Electrolytes for All-Solid-State Lithium Batteries Using Microsized Silicon/Carbon Anodes with Enhanced Rate Capability and Cyclability.

Silicon (Si) has been widely studied as one of the promising anodes for lithium-ion batteries (LIBs) because of its ultrahigh theoretical specific capacity and low working voltage. However, the poor interfacial stability of silicon against conventional liquid electrolytes has largely impeded its practical use. Therefore, the combination of silicon-based anodes and solid electrolytes has attracted a great deal of attention in recent years. Here, we demonstrate three types of microsized porous silicon/carbon (Si/C) electrodes (i.e., pristine, prelithiated by liquid electrolyte, and preinfiltrated by polymer electrolyte) that are paired with poly(ethylene) oxide (PEO)-based electrolytes for all-solid-state lithium batteries (ASSLBs). We found that when compared with ionic conductivity, the mechanical stability of the PEO electrolyte dominates the electrochemical performance of ASSLBs using Si/C electrodes at elevated temperature. Additionally, both prelithiated and preinfiltrated Si/C electrodes show higher specific capacity in comparison to the pristine electrode, which is attributed to continuous lithium-ion conducting pathways within the electrode and thus improved utilization of active material. Moreover, owing to good interfacial lithium-ion transport in the electrode, a solid-state half-cell with preinfiltrated Si/C electrode and PEO-lithium bis (trifluoromethanesulfonyl)imide electrolyte delivers a specific capacity of ∼1,000 mAh g-1 after 100 cycles under 800 mA g-1 at 60 °C with average Coulombic efficiency >98.9%. This work provides a strategy for rationally designing the microstructure of silicon-based electrodes with solid electrolytes for high-performance all-solid-state lithium batteries.

Preparation of Polycrystalline Silicon by Metal-Induced Crystallization of Silicon–Carbon Powder

Preparation of Polycrystalline Silicon by Metal-Induced Crystallization of Silicon–Carbon Powder

Effect of N2 reactive gas flow rate on the structural, optical and wettability properties of silicon carbon oxynitride thin films

In the current research, the silicon carbon oxynitride (SiCON) thin film was deposited on the silicon (Si) substrate by radio frequency (RF) reactive magnetron sputtering method. To comprehensively assess the impact of nitrogen flux rate on thin film characteristics, a suite of advanced analytical methods was utilized. The GIXRD analysis confirmed that the SiCON thin film is amorphous in structure. Additionally, Raman spectroscopy detected no graphite nanocrystals within the film. Ellipsometry measurements further showed that the refractive index of the thin films rises with increased nitrogen flux in the reactive gas, indicating a direct correlation between nitrogen concentration during deposition and optical properties. Based on the designs made with McLeod's software, the amount of reflection can be reduced up to 5.7 % at the wavelength of 4 μm and up to 8.5 % in the wavelength range of 3–5 μm for an optimal thickness thin film. The atomic force microscopy (AFM) examination revealed that the surface roughness of the thin films decreases as the nitrogen flux in the reactive gas mixture increases. Additionally, measurements of the water contact angle (WCA) indicated that the SiCON thin films exhibit a hydrophilic state.

Organophotocatalyzed C‐Si Bond Fragmentation Using Silyl Ethers as Radical Precursors

In this work, silyl ethers of phenols and alcohols have been successfully prepared and tested as neutral carbon (silicon) centered radical precursors. The organocophotocatalyzed oxidation (by the Fukuzumi catalyst) of these ethers caused the cleavage of a C‐Si (or a Si‐Si) bond for the release of the desired radical to be used for the forging of C(sp3)‐C(sp3) (or C(sp3)‐Si) bonds via a Giese reaction.

A Genetic Algorithm Trained Machine-Learned Interatomic Potential for the Silicon–Carbon System

A Genetic Algorithm Trained Machine-Learned Interatomic Potential for the Silicon–Carbon System

Effects of surface treatments for the adhesion improvement between Cu and SiCN in BEOL interconnect

This study focuses on the enhancement of interfacial reliability between Cu interconnects and silicon carbon nitride (SiCN) capping layers in semiconductor packaging structures through pre-deposition surface treatments. We compare three distinct treatments combined with H2 plasma, NH3 plasma, and SiH4 gas inflow, evaluating their effectiveness through quantitative measurement of interfacial adhesion energy using a double cantilever beam (DCB) fracture mechanics test. The results exhibit a remarkable adhesion energy improvement of over 1150 % with the addition of SiH4 gas treatment. Thorough investigations reveal that the mechanism of the exceptional adhesion enhancement is attributed to unique chemical bonding and fracture behavior. In other words, Si atoms in the SiH4 gas treatment incorporate onto Cu surfaces with specific crystallographic orientations, resulting in significantly stronger Cu–Si bonding in selective regions compared to other bondings. Moreover, the crystallographic-orientation-dependent bonding characteristic induces crack kinking at grain boundaries, dissipating the crack propagation energy. This work will provide crucial insight into enhancing the interfacial reliability and manufacturing yield of semiconductor devices.

Developing a piezoresistive sensor based bionic neurological intraoperative monitoring system for spine surgery skill training.

This research aims to tackle the limitations faced in surgical education nowadays, particularly in the complex field of spinal cord tumor removal surgery. An innovative flexible piezoresistive sensor designed to mimic a motor nerve was developed and integrated into a bionic spine surgery simulation system, allowing for the intraoperative nerve monitoring possible during simulated tumor removal surgeries. The motor nerve, fabricated using a combination of carbon nanotubes and silicone rubber, exhibited a strong correlation between applied force and resultant changes in resistance, as confirmed by experimental results. This creative system can play an important role in providing valuable feedback for training doctors, facilitating the assessment of surgical precision and success, and enabling doctors to take necessary precautions to minimize the risk of nerve damage in real surgical scenarios. Ultimately, this proposed system has the potential to elevate the standard of surgical education, foster skill development among doctors, and significantly contribute to enhanced patient care and recovery.

Establishing patterns in the structure formation of polymer nanocomposites based on polyamide 6 during their crystallization processes

This paper reports experimental and computational studies on patterns in the structure formation of polymer nanocomposites when different types of fillers are used. The study was conducted for nanocomposites based on polyamide 6 filled with carbon nanotubes or silicon dioxide nanoparticles. In the course of research, the mass fraction of the filler varied from 0.2 % to 4.0 %, and the cooling rate of the melt composite varied from 0.5 K/min up to 20 K/min. Data on experimental and theoretical studies into the mechanisms of structure formation of composites according to the method, which includes two stages, are given. According to the first stage, crystallization exotherms of nanocomposites were experimentally obtained when they are cooled from the melt at a given constant rate. The dependence of various characteristics of the crystallization process on the mass fraction of the filler and the cooling rate of the composite was established. At the second stage, based on the analysis of the obtained crystallization exotherms, theoretical studies were performed to determine the mechanisms of structure formation of nanocomposites at different stages of crystallization. For the initial stage, according to the nucleation equation, the presence of two mechanisms of structure formation – planar and volumetric – has been shown. Within the framework of the Kolmogorov-Avrami equation, the mechanisms of structure formation at the next stage of crystallization were established, which corresponds to the formation of ordered structures in the material within the volume of the polymer composite as a whole. The research was carried out assuming the existence of a mechanism of crystallization of the polymer matrix itself, which is realized on fluctuations in the density of the polymer, and a mechanism of crystallization, the centers of which are filler particles. The use of the proposed nanocomposites is promising for the manufacture of parts of energy equipment, electronic equipment, elements of chemical, processing, defense industry installations, etc.

Elucidating the role of embedding dispersed cobalt sites in nitrogen-doped carbon frameworks in Si-based anodes for stable and superior storage

Unsatisfactory conductivity and volume effects have hindered the commercial application of silicon-based materials as advanced anode materials for high-performance lithium-ion batteries. Herein, nitrogen doped carbon silicon matrix composite with atomically dispersed Co sites (Si/Co-N-C) is obtained via the design of the frame structure loaded with nano-components and the multi-element hybrid strategy. Co atoms are uniformly fixed to the N-C frame and tightly packed with nanoscale silicon particles as an activation and protection building block. The mechanism of the N-C framework of loaded metal Co in the Si alloying process is revealed by electrochemical kinetic analysis and ex situ characterization tests. Impressively, the nitrogen-doped Co site activates the intercalation of the outer carbon matrix to supplement the additional capacity. The Co nanoparticles with high conductivity and support enhance the conductivity and structural stability of the composite, accelerating the Li+/Na+ diffusion kinetics. Density functional theory (DFT) calculation confirms that the hetero-structure Si/Co-N-C adjusts the electronic structure to obtain good lithium-ion adsorption energy, reduces the Li+/Na+ migration energy barrier. This work provides meaningful guidance for the development of high-performance metal/non-metal modified anode materials.

Impedance Inhomogeneity in SiO/Gr Composite Anode

Silicon/carbon (Si/C) composite anode materials have emerged as promising candidates for high‐energy‐density lithium‐ion batteries (LIBs), boasting advantages such as high capacity, cost‐effectiveness, and abundance. However, the integration of Si‐based materials into conventional graphite anodes introduces heterogeneous interactions between electrochemical and mechanical behaviors, owing to substantial volume changes and chemical potential variations. One significant consequence of these interactions is the impedance inhomogeneity, which adversely affects the discharging capacity of Si‐based LIBs. In an effort to comprehensively understand this phenomenon and its underlying mechanisms, an electrochemo‐mechanical‐coupled model is established, incorporating detailed particle geometries on the anode side. The model is employed to investigate polarization components and their evolution during the charging/discharging process. Various influencing factors, such as SiO weight percentage (wt%), electrode thickness, and SiO distributions (both in terms of distribution uniformity and direction), are systematically discussed. In this study, an efficient computational approach is offered to analyze battery polarizations, deepening the understanding of the inhomogeneous evolution of these polarizations in Si/C composite anodes. Ultimately, these insights guide the design of anodes for next‐generation high‐energy‐density LIBs.

Formation and stability of point defect color centers in 6H silicon carbide

Point defect color centers acting as single-photon emitters are promising for quantum technology applications and have been extensively studied, e.g., in the 4H polytype of silicon carbide (SiC). However, the physics of such color centers in other SiC polytypes is much less explored. Herein, we study the formation and thermal stability of such color centers in 6H-SiC using photoluminescence spectroscopy. The emissions from typical single-photon emitters, such as silicon vacancies, divacancies, and carbon antisite-vacancy pairs in 6H-SiC, were monitored as a function of the proton irradiation fluence and post-irradiation annealing, and compared to that in 4H-SiC. Overall, at the background of similarities between the emission behavior in 4H- and 6H-SiC polytypes, we observed prominent differences; e.g., for the thermal stability of the carbon antisite-vacancy pair, which exhibited maximized emissions upon 300 and 900 °C anneals in 4H- and 6H-SiC, respectively. Moreover, we observed a range of defect emission signatures not previously reported for 6H-SiC in the literature and discussed their potential origin in the context of the thermal stability. For example, among the PL-lines in 6H-SiC, we detected periodically repeatable emission signatures, resembling the so-called L-lines recently reported in 4H-SiC, even though their exact origin has not yet been settled in the literature. Thus, we use color centers comparison in different polytypes to better understand the nature of the single-photon emitters in SiC.

Novel binary regulated silicon-carbon materials as high-performance anodes for lithium-ion batteries

The massive volume dilation, unsteady solid electrolyte interphase, and weak conductivity about Si have failed to bring it to practical applications, although its potential capacity is up to 4200 mAh g−1. For solving these problems, novel binary regulated silicon–carbon materials (Si/BPC) were done by a sol–gel procedure combined with single carbonization. Analytical techniques were systematically utilized to examine the effects of element doping at several gradients on morphology, structure and electrochemical properties of composites, thus the optimal content was identified. Si/BPC preserves a discharge specific capacity of 1021.6 mAh g−1 with a coulomb efficiency of 99.27% after 180 cycles at 1000 mA g−1, within the upgrade than single-doped and undoped. In rate test, it has a specific capacity of 1003.2 mAh g−1 at a high current density of 5000 mA g−1, quickly back towards 2838.6 mAh g−1 at 200 mA g−1. The inclusion of B and P elements is linked to the electrochemical characteristics. In the co-doped carbon layers, the synergistic impact of doping B and P accelerates the diffusion kinetics of lithium ions, boosts diffusion rate of Li+, offers low electrochemical impedance (45.75 Ω). This brings more defects to provide transport carriers and induces a substantial amount of electrochemically active sites, which fosters the storage of Li+, thus making silicon material electrochemically more active and potential.

Clinical Application of Nano Field-Effect Transistor Biosensor in the Detection of Biomarkers

Field-effect transistor (FET)-based biosensors exhibit excellent performance characteristics such as small size, ease of mass production, high versatility, and comparably low cost. In recent years, numerous FET biosensors based on various nanomaterials including silicon nanowires, carbon nanotubes, graphene, and transition metal dichalcogenides have been developed to detect a wide range of biomarkers that play a crucial role in early disease diagnosis, therapeutic monitoring and prognostic assessment. This review provides an overview of the structure, working principle, functionalization strategies and detection factors associated with FET biosensors based on diverse nanomaterials. Additionally, this paper discusses the applications of these diagnostic devices for detecting clinically relevant biomarkers such as nucleic acids, metabolites, proteins, cancer biomarkers, and hormones among others. The concluding section provides a comprehensive overview of the numerous challenges encountered in the widespread implementation of nanomaterial-based FET biosensors for clinical detection, while also presenting the future prospects for these biosensors based on current research advancements.

Investigation of the mechanical and thermal properties of epoxy adhesives reinforced by carbon nanotubes and silicon dioxide nanoparticles in single-lap joints

In this study, the shear strength and thermal properties of the adhesively bonded joints were investigated of adhesives reinforced with nanoparticles using carbon fiber-reinforced composite materials. The diglycidyl ether bisphenol A (DGEBA) was used as the epoxy resin. Single lap joint tests of 1% wt. Multi-walled carbon nanotubes (MWCNT) and 3, 5, and 7% wt. silicon dioxide (SiO2) nanoparticle-reinforced mixed adhesives were performed according to ASTM D5868 standards. The shear strengths of the mixed adhesives obtained by mixing at different ratios were compared with the epoxy resin. Upon conducting an analysis of the shear strengths of nanomaterials, results indicate that the incorporation of 1CNT + 3SiO2 in the nanomaterials showed the greatest improvement, with a 46% increase in shear strength. 1CNT + 5SiO2, 1CNT, and 1CNT + 7SiO2 showed increases of 32%, 14%, and 5%, respectively. The results of a tensile test indicate that pure epoxy exhibited a tensile strength of 5953 N, 1CNT, and 3SiO2, while the epoxy composite demonstrated a significantly higher tensile strength of 8738 N, along with an elongation of 0.72 mm. In addition, the morphology of fractured surfaces was examined by scanning electron microscopy (SEM). To investigate damage mechanisms, such as bridging, crack blunting, and branching of nanoparticles were observed. Characterization of epoxy resin and mixed MWCNT + SiO2 nanoparticles reinforced adhesives were also performed using Fourier infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Nanoparticles are settled between polymer chains, improving polymer chains’ motion and thermal properties.