Mid Sweden University

This paper presents research on the synergistic effects of nickel molybdate and reduced graphene oxide as a nanocomposite for further development of energy storage systems. An enhancement in the electrochemical performance of supercapacitor electrodes occurs by synthesizing highly porous structures and achieving more surface area. In this work, a chemical precipitation technique was used to synthesize the NiMoO4/3D-rGO nanocomposite in a starch media. Starch was used to develop the porosities of the nanostructure. A temperature of 350◦C was applied to transform graphene oxide sheets to reduced graphene oxide and remove the starch to obtain the NiMoO4/3D-rGO nanocomposite with porous structure. The X-ray diffraction pattern of the NiMoO4 nano particles indicated a monoclinic structure. Also, the scanning electron microscope observation showed that the NiMoO4 NPs were dispersed across the rGO sheets. The electrochemical results of the NiMoO4/3D-rGO electrode revealed that the incorporation of rGO sheets with NiMoO4 NPs increased the capacity of the nanocomposite. Therefore, a significant increase in the specific capacity of the electrode was observed with the NiMoO4/3D-rGO nanocomposite (450 Cg−1 or 900 Fg−1) when compared with bare NiMoO4 nanoparticles (350 Cg−1 or 700 Fg−1) at the current density of 1 A g−1. Our findings show that the incorporation of rGO and NiMoO4 NP redox reactions with a porous structure can benefit the future development of supercapacitors. 

Although Graphene oxide (GO)-based materials is known as a favorable candidate for supercapacitors, its conductivity needs to be increased. Therefore, this study aimed to investigate the performance of GO-based supercapicitor with new methods. In this work, an ammonia solution has been used to remove the oxygen functional groups of GO. In addition, a facile precipitation method was performed to synthesis a NiMoO4/3D-rGO electrode with purpose of using synergistic effects of rGO conductivity properties as well as NiMoO4 pseudocapacitive behavior. The phase structure, chemical bands and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), Raman spectroscopy, and field emission secondary electron microscopy (FE-SEM). The electrochemical results showed that the NiMoO4/3D-rGO(II) electrode, where ammonia has been used during the synthesis, has a capacitive performance of 932 Fg(-1). This is higher capacitance than NiMoO4/3D-rGO(I) without using ammonia. Furthermore, the NiMoO4/3D-rGO(II) electrode exhibited a power density of up to 17.5 kW kg(-1) and an energy density of 32.36 Wh kg(-1). These results showed that ammonia addition has increased the conductivity of rGO sheets, and thus it can be suggested as a new technique to improve the capacitance.

Ambient gamma radiation study was carried out in South Konkan using thermo luminescent dosimeters (TLDs). A statistical analysis was carried out to understand the distribution of gamma radiation in the study area. The annual effective doses (AEDs) received by the local population from the selected villages were 0.31 and 0.09 mSv year−1 for indoor and outdoor locations, respectively. For indoor conditions, the maximum dose rate occurred for winter season and the minimum occurred in monsoon season while for outdoor conditions the maximum dose rate occurred in spring season and minimum occurred in the monsoon season. The terrestrial radioactivity in the corresponding villages was measured by a HpGe detector. The radiation hazard indices like absorbed dose rate in air (D), radium equivalent activity (Raeq), external hazard index (H ex) and internal hazard index (H in), and AED were calculated using soil radioactivity data. The minimum absorbed dose rate in air (33.97 nGy h−1) corresponds to the Dale village and the maximum (101.86 nGy h−1) corresponds to the Mithgawane village. Radiation hazard indices as Raeq, H ex, and H in were found to be within the limit. The average AED from natural radionuclides was found to be lower than the worldwide value. The AEDs of this study were compared with previous studies carried out worldwide. A positive correlation was observed for the absorbed dose rate in air and the activity concentration of U-238, Th-232, and K-40. A positive correlation between activity concentrations of U-238, Th-232, and K-40 was also observed. The comparison between the AEDs calculated using absorbed dose measured by TLDs and the values calculated from soil’s gamma spectrometry showed some variation in the villages of South Konkan.

In this investigation, we have successfully synthesized CdS nanorods by simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. The effect of film thickness on the physico-chemical properties such as structural, morphological, wettability, optical, and electrical properties of CdS nanorods has been investigated. The XRD pattern revealed that CdS films are polycrystalline with hexagonal crystal structure. SEM and TEM images showed that CdS film surface are composed of spherical grains along with some spongy cluster and an increase in film thickness up to 1.23 μm causes the formation of matured nanorods having diameter 150–200 nm. The increases in water contact angle form 105° to 130° have been observed as film thickness increases from 0.13 to 1.23 μm indicating hydrophobic nature. The optical band gap was found to be increased from 2.02 to 2.2 eV with increase in film thickness. The films showed the semiconducting behavior with room temperature electrical resistivity in the range of 10⁴–10⁶ Ω cm and have n-type electrical conductivity.

Structural, magnetic properties and alternating current (AC) magnetic heating characteristics of Fe0.7Mn0.3Fe2O4 nanoparticles have been investigated with respect to the possible application for magnetic hyperthermia. The specific absorption rate (SAR) was measured in alternating magnetic fields of 84.44–251.4Oe at fixed frequency of 289 kHz. Fe-Mn NPs were fabricated by the chemical co-precipitation method using sodium hydroxide as the precipitating agent and citric acid as capping agent. The morphology of the particles was analyzed by transmission electron microscopy (TEM). The TEM reveals that the grains are nearly spherical in shape with average particles size of 10nm. X-ray diffraction pattern indicated the sole existence of cubic spinel phase of Fe-Mn NPs with lattice parameter a=8.3419 Å. Formation of the spinel Fe-Mn ferrite was also supported by Fourier Transform Infrared Spectroscopy. The saturation magnetization (Ms) is 40emu/g with superparamagnetic nature of the sample. The magnetic heating ability of NPs was studied with an induction heating system. A highest SAR value of 78.85W/g for 2mg/mL sample concentration (289 kHz, 335.2Oe) was observed.

This paper reveals the structural, magnetic and heating ability of citric acid coated Fe0.3Mn0.7GdxFe2−xO4 (x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) nanocrystalline ferrites. The synthesis of Gd-doped Fe–Mn ferrite nanoparticles (NPs) is confirmed by XRD studies. Substitution of Gd3+ions in Fe–Mn ferrite causes the lattice constant enhancement from 8.3286 to 8.4699 Å. The cation distribution reveals that Gd3+ ions preferred the octahedral sites of Fe–Mn ferrite. The average crystallite size is around 10–12 nm. The Fe–Mn–Gd spinel ferrite NPs are also characterized by FTIR studies and supports its formation. The saturation magnetization increases with Gd-content, take its maximum value for x = 0.06 and drops further for higher x values. The change in saturation magnetization show a connection with the structural modifications; because of replacement of Gd3+ ions at the place of Fe3+ ions in the octahedral site (B-site), it modifies A and B sublattices superexchange interactions. The heating abilities of these nanoparticles are studied by applying different alternating magnetic fields at constant frequency 289 kHz. When referred to the Gd-content, the SAR exhibits similar variation as saturation magnetization (Ms) and anisotropy constant (K), the later being more dominant. The highest value of SAR is 640 W/g for Fe0.3Mn0.7Gd0.06Fe1.94O4 sample under an applied field 251.4 Oe. It is seen that SAR is increased by nearly six times as compared to pristine Fe0.3Mn0.7Fe2O4 nanoparticles. The present results suggest that magnetic field controlled therapeutic temperature can be easily achieved within 1 min using such nanoparticles. 

Graphite is central in almost all commercial Li-ion batteries (LIBs) and possesses attractive physical and chemical properties such as good ionic conductivity and layered graphitic structure. In this communication, we have demonstrated the recycling of graphite from end-of-life LIBs and the re-purposing of the recovered material for positive electrodes in next-generation aluminium-ion-batteries (AIBs). The recovered graphite possesses enlarged interlayer spacing which is shown to effectively boost Al-ion insertion/de-insertion during the charge/discharge processes. Excellent Al-ion storage performance is achieved with the capacity reaching 124 mAh g−1 at 50 mA g−1. The material retained a capacity of 55 mAh g−1 even after the applied current was increased to 500 mA g−1, showing its capability to deliver high rate performance. The charge/discharge cycling further revealed that the graphite retains 81% of its initial capacity even after 6700 cycles at a high rate of 300 mA g−1. This excellent aluminium ion storage performance makes the recovered graphite a promising positive electrode material, providing a possible solution for the recycling of huge amounts of LIB scrap. At the same time, this material aids the development of alternative sustainable battery technology, as an alternative to LIBs.

La_0.7Sr_0.3MnO₃ (LSMO) nanoparticles with a size of ∼23 nm have been prepared by a combustion method and functionalized with polyvinylpyrrolidone (PVP) for their possible application in magnetic fluid hyperthermia (MFH). Uncoated and PVP-coated samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and vibrating sample magnetometer studies. Magnetic measurements of both coated and uncoated particles reveal the superparamagnetic nature at room temperature. Colloidal stability has been measured in terms of zeta potential. The resulting PVP-coated particles form a stable suspension in phosphate buffer saline (PBS) and double distilled water (DDW) and possess a narrow hydrodynamic size distribution. The induction heating studies of these nanoparticles at different alternating magnetic fields (167.6, 251.4 and 335.2 Oe) were carried out by dispersing nanoparticles in DDW and PBS. These PVP-coated LSMO NPs exhibit a higher specific absorption rate in PBS than in DDW. The results suggest that combustion-synthesized LSMO nanoparticles coated with PVP can be used as potential heating agents in MFH.

Nanocrystalline powder of MgFe₂O₄ was successfully synthesized by a cost effective novel combustion route. Nitrates of the constituent elements and glycine were respectively used as an oxidizer and fuel to drive the reaction. The effect of glycine to nitrate molar ratio (G N⁻¹) on the structure and formation of MgFe₂O₄ was studied in view of thermodynamic considerations like adiabatic flame temperature and gas evolved during the combustion. The as prepared powder was characterized by X-Ray Diffraction (XRD), Fourier Transform Infra Red (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) for formation and microstructure analysis at various G N⁻¹ ratios. XRD results revealed that the crystallinity of MgFe₂O₄ is insensitive to G N⁻¹ variations and fuel lean combustion also lead to appropriate MgFe₂O₄ phase formation. Thermo Gravimetric-Differential Thermal Analysis (TG-DTA) for the precursor gel demonstrated the occurrence of rapid chemical reaction between glycine and nitrates at around 194 °C corresponding to ignition of precursors at this temperature. Transmission electron microscopy image for as prepared stoichiometric sample shows formation of nanoparticles of sizes from 28 nm to 50 nm. SEM images of MgFe₂O₄ nanoparticles at G N⁻¹ ratio show remarkable change in microstructure regarding porosity and grain size. Room temperature magnetic measurements for stoichiometric sample show the magnetization (M_s) and remanence (M_r) of about 31.56 emu g⁻¹ and 9.60 emu g⁻¹ at ±10 kOe respectively.

Nanoferrites having composition Mn_xMg_1−xFe₂O₄(x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) are synthesized by a low-temperature combustion method. The particle size measured from transmission electron microscopy and x-ray diffraction (XRD) patterns confirms the nanosized dimension of the as-prepared powder. From the analysis of XRD data with Scherrer's formula, the average crystallite size ranges from 23 to 33 nm and the lattice parameter ranges from 8.385 to 8.468 Å. Substitution of Mn²⁺ in MgFe₂O₄ causes an increase in the lattice constant, and this moderately distorts the lattice. Magnetic properties such as magnetization (M_s), coercivity (H_c) and remanence (M_r) with increasing Mn²⁺ concentration are studied at room temperature by a vibrating sample magnetometer. Substitution of Mn²⁺ for Mg²⁺ increases M_s from 34.5 to 54.5 emu g⁻¹ and decreases H_c from 51.0 to 45.0 Oe. The results imply that the low-temperature combustion method is an efficient route for synthesis of nanoferrites without any extra calcination step. The as-prepared Mg–Mn ferrites are suitable for memory and switching circuits in digital computers.

The structural, magnetic and ac magnetically induced heating characteristics of combustion synthesized MgFe₂O₄ nanoparticles have been investigated for application in magnetic particle hyperthermia. As prepared nanoparticles showed ferrimagnetic behavior at room temperature with magnetization of about 33.83 emu/g at ±15 kOe. The solid state MgFe₂O₄ nanoparticles exhibited specific absorption rate (SAR) of about 297 W/g at physiological safe range of frequency and amplitude. The increase in SAR and heating temperature in ac magnetic field was thought to be due to enhancement in magnetic hysteresis loss caused by dipole–dipole interactions in combustion synthesized MgFe₂O₄ nanoparticles.

A green synthesis of biocompatible magnetite (Fe3O4) nanoparticles (MNPs) using a combination of urea (U) and gram-bean extract (GBE, Cicer arietinum L.) is reported. The particle size of similar to 13 nm and highly stable magnetite phase is observed for GBE-U mediated MNPs. On the other hand, the MNPs synthesized using either U or GBE shows larger particle size and uneven size distribution. Interestingly, the sample with particle size similar to 13 nm shows optimum heat generation capacity (measured in specific absorption rate, i.e., SAR) near to the therapeutic temperature (43 degrees C) with least-variance. To investigate the influence of various factors such as variation in MNPs weight concentration (W-t), applied alternating magnetic field (AMF), saturation magnetization (M-s), magnetization rate (R-m), etc. on SAR, a multiple linear regression model (MLRM) is used. The study reveals a positive correlation of SAR with R-m, and AMF values while the negative correlation with M-s and W-t. Ultimately, the present green synthesis is the affordable approach for preparing stable and tiny MNPs. Moreover, MLRM is found to be a useful theoretical tool for understanding the influence of MNPs on hyperthermia performance. 

Zinc oxide (ZnO) nanoparticles (NPs) have a wide range of biomedical applications. Present study demonstrates the new methodology in sol-gel technology for synthesizing Polyethylene glycol (PEG) capped ZnO NPs and its size effect on anti-microbial activity. The reaction time was increased from 1 h to 5 h for the synthesis of ZnO NPs at 130 °C. The size of PEG capped ZnO NPs is increased from 10 to 84 nm by increasing the reaction upto 5 h. The x-ray diffraction studies and transmission electron microscopy analysis reveals the phase purity and hexagonal wurtzite crystal structure with uniform PEG capping on the surface of ZnO NPs. UV–visible spectroscopy exhibits the peak at 366 nm which is attributed to ZnO NPs. No adverse effect is observed in case of absorbance spectroscopy. Further, Fourier transforms infrared spectroscopy and thermo gravimetric analysis depicts the adsorption of PEG molecules on the ZnO NPs surface. The anti-microbial activities for both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria were studied by optical density (OD) mesurement. The remarkable anti-microbial activity was observed for PEG capped ZnO NPs synthesized at 1 h reaction time showing higher activity in comparison with that synthesized from 2 h to 5 h reaction time. The microbial growth was found to be inhibited after 10 h OD measurement for both the bacteria. The anti-microbial activity may be attributed to the generation of ROS and H2O2. However, these generated species plays a vital role in inhibition of microbial growth. Hence, PEG capped ZnO NPs has promising biomedical applications.

Initially micro-organisms get exposed to the surfaces, this demands development of anti-microbial surfaces to inhibit their proliferation. Therefore, herein, we attempt screen printing technique for development of PVA-GE/ZnO nanocomposite (PG/ZnO) films. The synthesis of PG/ZnO nanocomposite includes two steps as: (i) Coating of Zinc Oxide nanoparticles (ZnO NPs) by poly ethylene glycol in order to be compatible with organic counterparts. (ii) Deposition of coated nanoparticles on the PG film surface. The results suggest the enhancement in anti-microbial activity of PG/ZnO nanocomposite over pure ZnO NPs against both Gram positive Bacillus subtilis and Gram negative Escherichia coli from zone of inhibition. The uniformity in deposition is further confirmed by scanning electron microscopy (SEM) images. The phase identification of ZnO NPs and formation of PG/ZnO nanocomposite has been confirmed by X-ray diffraction (XRD) analysis and UV–vis spectroscopy (UV–vis). The Attenuated total reflection Spectroscopy (ATR) analysis indicates the ester bond between PVA and gelatin molecules. The thermal stability of nanocomposite is studied by thermogravimetric analysis (TGA) revealing increase in crystallinity due to ZnO NPs which could be utilized to inhibit the growth of micro-organisms. The tensile strength is found to be higher and percent elongation is double of PG/ZnO nanocomposite than PG composite film.

Structural, magnetic properties and an alternating current (AC) magnetic heating characteristics of Co0.5Zn0.5Fe2O4 nanoparticles (CZF NPs) have been investigated with respect to the possible application for magnetic hyperthermia treatments. The Specific Absorption Rate (SAR) was measured in alternating magnetic fields of 167.5–335.2 Oe at fixed frequency of 265 kHz. CZF NPs were fabricated by the chemical co-precipitation method using sodium hydroxide (NaOH) as the precipitating agent. The morphology of the particles was analysed by Transmission Electron microscopy (TEM). The TEM reveals that the grains are nearly spherical in shape with average particles size of 19 nm. X-ray diffraction pattern indicated the sole existence of cubic spinel phase of CZF NPs. The magnetization (Ms) of CZF NPs was measured at room temperature (300 K) using a Vibrating Sample Magnetometer (VSM). The magnetic heating ability of NPs was studied with an induction heating system. A highest SAR value of 114.98 W/g for 5 mg/mL sample concentration (265 kHz, 335.2 Oe) was determined

Silicon anodes are considered as promising electrode materials for next-generation high-capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge−discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in the recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nano graphite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.

The NiFe₂O₄ nanoparticles were prepared by the combustion method and these nanoparticles were successfully coated with polyethylene glycol (PEG) for the possible biomedical applications such as magnetic resonance imaging, drug delivery, tissue repair, magnetic fluid hyperthermia etc. The structural and magnetic characterizations of NiFe₂O₄ nanoparticles were carried out by x-ray diffraction and vibrating sample magnetometry techniques, respectively. The morphology of the uncoated and coated nanoparticles was studied by scanning electron microscopy. The existence of PEG layer on NiFe₂O₄ nanoparticles was confirmed by fourier transform infrared spectroscopy technique.

Conversion of electromagnetic energy into heat by nanoparticles (NPs) has the potential to be a powerful, non-invasive technique for biomedical applications such as magnetic fluid hyperthermia, drug release, disease treatment and remote control of single cell functions, but poor conversion efficiencies have hindered practical applications so far. In this paper, an attempt has been made to increase the efficiency of magnetic thermal induction by NPs. To increase the efficiency of magnetic thermal induction by NPs, one can take advantage of the exchange coupling between a magnetically hard core and magnetically soft shell to tune the magnetic properties of the NP and maximize the specific absorption rate, which is the gauge of conversion efficiency. In order to examine the tunability of magnetocrystalline anisotropy and its magnetic heating power, a representative magnetically hard material (CoFe2O4) has been coupled to a soft material (Ni0.5Zn0.5Fe2O4). The synthesized NPs show specific absorption rates that are of an order of magnitude larger than the conventional one.

To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.

NiMn2O4 (NMO) is a good alternative anode material for lithium-ion battery (LIB) application, due to its superior electrochemical activity. Current research shows that synthesis of NMO via citric acid-based combustion method envisaged application in the LIB, due to its good reversibility and rate performance. Phase purity and crystallinity of the material is controlled by calcination at different temperatures, and its structural properties are investigated by X-ray diffraction (XRD). Composition and oxidation state of NMO are further investigated by X-ray photoelectron spectroscopy (XPS). For LIB application, lithiation delithiation potential and phase transformation of NMO are studied by cyclic voltammetry curve. As an anode material, initially, the average discharge capacity delivered by NMO is 983 mA center dot h/g at 0.1 A/g. In addition, the NMO electrode delivers an average discharge capacity of 223 mA center dot h/g after cell cycled at various current densities up to 10 A/g. These results show the potential applications of NMO electrodes for LIBs.

The effect of fuel characteristics on the processing of nano-sized cobalt ferrite fine powders by the combustion technique is reported. By using different combinations of glycine fuel and metal nitrates, the adiabatic flame temperature (T_ad) of the process as well as product characteristics could be controlled easily. Thermodynamic modelling of the combustion reaction shows that as the fuel-to-oxidant ratio increases, the amount of gases produced and adiabatic flame temperatures also increases. The powders obtained by combustion were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo gravimetric analysis and differential thermal analysis (TG–DTA), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) measurements. The particle size of phase pure cobalt ferrite nanoparticles was found to be <40 nm in this investigation. The effects of glycine addition with stoichiometric (ϕ = 1), fuel lean (ϕ < 1) and fuel rich (ϕ > 1) precursor batches were investigated separately.

In the present work, Co_1−xMn_xFe₂O₄ nanoparticles were synthesized by the low-temperature auto-combustion method. The thermal decomposition process was investigated by means of differential and thermal gravimetric analysis (TG-DTA) that showed the precursor yield the final product above 450 °C. The phase purity and crystal lattice symmetry were estimated from X-ray diffraction (XRD). Microstructural features observed by scanning electron microscopy (SEM) demonstrates that the fine clustered particles were formed with an increase in average grain size with Mn²⁺ content. Fourier transform infrared spectroscopy (FTIR) study confirms the formation of spinel ferrite. Room temperature magnetization measurements showed that the magnetization M_s increases from 29 to 60 emu/g and H_c increases from 13 to 28 Oe with increase in Mn²⁺ content, which implies that these materials may be applicable for magnetic data storage and recording media.

In the present work, cobalt ferrite nanoparticles (CoFe₂O₄ NPs) have been synthesized by combustion method. The surface of the CoFe₂O₄ NPs was modified with biocompatible polyvinyl alcohol (PVA). To investigate effect and nature of coating on the surface of CoFe₂O₄ NPs, the NPs were characterized X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and dynamic light scattering (DLS) results demonstrate the monodispersed characteristics of CoFe₂O₄ NPs after surface modification with PVA. The decrease in contact angle from 162° to 50° with PVA coating on NPs indicates the transition from hydrophobic nature to hydrophilic. The Magnetic properties measurement system (MPMS) results show that the NPs have ferromagnetic behavior with high magnetization of 75.04 and 71.02 emu/g of uncoated and coated CoFe₂O₄ NPs respectively. These PVA coated NPs exhibit less toxicity over uncoated CoFe₂O₄ NPs up to 1.8 mg mL⁻¹ when tested with mouse fibroblast L929 cell line.

Sol gel technique in combination with spin coating method was utilized for the synthesis of silica thin films. Tetraethyl orthosilicate (TEOS) alkoxide silane precursor was used for one step synthesis of silica sol with 0.1M HCL as catalyst. Casting solution of silica sol was spin coated on glass substrate. The X-ray diffraction pattern revealed that the sample possesses amorphous silica matrix. Thin films were characterized by Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy techniques to compare the effect of TEOS concentration. The optical properties of the silica thin films revealed that thin films have 90-95% transmittance in the visible range.

Silicon dioxide (SiO2 or Silica) is one of the most prevalent substances in the crust of the Earth. The main varieties of crystalline silica are quartz, cristobalite, and tridymite. When applied as a material for energy, it is affordable and eco-friendly. The SiO2 is considered as electrochemically inactive toward lithium. The SiO2 exhibits low activity for diffusion and inadequate electrical conductivity. As the particle size of SiO2 decreases, the diffusion pathway of Li-ions shortens, and the electrochemical activity is promoted. In investigation, Cost-effective synthesis approach was employed to produce crystalline cristobalite alpha low silicon dioxide nanoparticles (CCαL SiO2 NPs) derived from Oryza sativa (rice) husk using a solvent extraction modification technique. The objective was to fabricate an cost-effective future anode nanomaterial that could reduce the significant volume expansion growth, pulverization, and increase electrical conductivity of CCαL SiO2 NPs anode and develop high specific capacity for Lithium-ion battery (LiB). To study the phase and purity of the SiO2, a variety of characterization methods, including X-Ray Diffraction, Fourier Infra-Red Spectroscopy, Surface area analysis, Raman Shift analysis, Field Emission Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy, Contact angle measurement, Post-mortem X-ray diffraction, and Post-mortem field emission scanning electron microscopy were employed. This cost-effective synthesis of CCαL SiO2 NPs anode was first reported in this work.

This study investigates the performance of silicon nanoparticles (Si NPs) and silicon nanographite (SiNG) composite-based anodes for lithium-ion batteries (LiBs). Si offers a promising alternative to traditional graphite anodes due to its higher theoretical capacity, despite encountering challenges such as volume expansion, pulverization, and the formation of a solid electrolyte interface (SEI) during lithiation. SiNPs anode exhibited initial specific capacities of 1568.9 mAh/g, decreasing to 1137.6 mAh/g after 100th cycles, with stable Li–Si alloy phases and high Coulombic efficiency (100.48%). It also showed good rate capability, retaining 1191.3 mAh/g at 8400 mA g−1 (2.82C), attributed to its carbon matrix structure. EIS indicated charge transfer with RB of 3.9 Ω/cm−2 and RCT of 11.4 Ω/cm−2. Contrastingly, SiNG composite anode had an initial capacity of 1780.7 mAh/g, decreasing to 1297.5 mAh/g after 100 cycles. Its composite structure provided cycling stability, with relatively stable capacities after 50 cycles. It exhibited good rate capability (1191.3 mAh/g at 8399.9 mA g−1), attributed to its carbon matrix structure. Electrochemical impedance spectroscopy showed higher resistances for RB of 4.2 Ω/cm−2 and RCT of 15.6 Ω/cm−2 compared to SiNPs anode. These findings suggest avenues for improving energy storage devices by selecting and designing suitable anode materials.

Graphene-based 2D nanomaterials are gaining much interest in energy storage systems, specifically in ultracapacitors. Various electrolytes increase the performance of ultracapacitor (UC), Li-Ion capacitor (LIC), and Li-Ion battery (LIB). In the present work, we have successfully designed a "three-in-one" artificial method to engineer anode from a single precursor for high-performance UC, LIC, and LIB. In the present investigation, graphene oxide (GO) slurry was developed using the modified Hummers’ method. The effect of KOH, H2SO4, and KCl electrolytes on electrochemical performance of UC was demonstrated. The LiPF6 organic electrolyte solution on electrochemical performance of LIC and LIB is demonstrated. The GO deposited on stainless steel electrode achieved its highest specific capacitance of 422 F/g, energy density of 45.50 kWh/kg, and power density of 10,000 W/kg in 3.0 M in KCl, whereas GO as an anode material delivered a first discharge capacity of 456 mAh/g at 0.05 A/g current density with the efficiency of 100%.

Core–shell structures with magnetic core and metal/polymer shell provide a new opportunity for constructing highly efficient mediator for magnetic fluid hyperthermia. Herein, a facile method is described for the synthesis of superparamagnetic LSMO@Pluronic F127 core–shell nanoparticles. Initially, the surface of the LSMO nanoparticles is functionalized with oleic acid and the polymeric shell formation is achieved through hydrophobic interactions with oleic acid. Each step is optimized to get good dispersion and less aggregation. This methodology results into core–shell formation, of average diameter less than 40 nm, which was stable under physiological conditions. After making a core–shell formulation, a significant increase of specific absorption rate (up to 300%) has been achieved with variation of the magnetization (< 20%). Furthermore, this high heating capacity can be maintained in various simulated physiological conditions. The observed specific absorption rate is almost higher than Fe3O4. MTT assay is used to evaluate the toxicity of bare and core–shell MNPs. The mechanism of cell death by necrosis and apoptosis is studied with sequential staining of acridine orange and ethidium bromide using fluorescence and confocal microscopy. The present work reports a facile method for the synthesis of core–shell structure which significantly improves SAR and biocompatibility of bare LSMO MNPs, indicating potential application for hyperthermia.

Biometric signatures based on either the physiological or behavioural features of a person have been widely used for identification and authentication. However, few strategies have been developed that combine the two types of features in one signature. Here, we report a type of biometric signature based on the triboelectricity of the human body (TEHB) that combines these two types of features. This triboelectric biometric signature (TEBS) can be accomplished by anyone regardless of the physical condition, as it can be performed by many parts of the body. Different TEBS can be identified using a convolutional neural network (CNN) model with a test accuracy of up to 1.0. The TEBS has been further used for text encryption and decryption with a high sensitivity to changes. Moreover, a dual signed digital signature for enhanced security has been proposed. Our findings provide a new type of TEBS that can be generally used and demonstrated in applications.