Mid Sweden University

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.

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.

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%.

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. 

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.

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.

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.

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. 

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.