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Hydroxyl terminated poly(dimethylsiloxane) (PDMS-HT) is used as an electrolyte additive in electrolyte systems containing 1 M LiPF6 in EC:DMC (ratios 1:9; 3:7; 4:6 and 1:1 v/v) to enhance the cycle performance of lithium-ion batteries. Adding a small amount of PDMS-HT to the standard LIB electrolyte leads to improved specific capacity as well as improved capacity retention over prolonged cycles. There is also a slight increase in Li+ ion conductivity when PDMS-HT is added. Also, the PDMS-HT additive allows the formation of a more stable solid electrolyte interface (SEI) layer that enables the LIB cells to be cycled for longer cycles with minimal capacity fading. This combination of improved ionic conductivity and stable SEI layer formation due to the PDMS-HT additive, makes it an excellent candidate for an electrolyte additive for lithium ion batteries.

Enhanced microwave absorption properties were successfully achievable from SrFe2-xZnxFe16O27 (SrFe2-xZnxW; x = 0.0, 0.5, 1.0, and 2.0) hexaferrite filler-epoxy resin matrix composites. The composite samples were fabricated with the filler volume fractions (Vf) of 30, 50, 70, and 90%. Compared with fully Zn-substituted SrZn2W composite (x = 2.0), unsubstituted and partially Zn-substituted SrFe2-xZnxW (x = 0.0, 0.5, and 1.0) composites exhibited much higher real and imaginary parts of complex permittivity (er), which is attributable to higher electron hopping between Fe2+ and Fe3+ ions, and also slightly higher real and imaginary parts of complex permeability (μr) due to higher saturation magnetization (Ms). Among all samples, a 2.8 mm-thick SrFe1·5Zn0·5W (x = 0.5) composite with the Vf of 90% exhibited the most appropriate for application in the region of 3.4–3.8 GHz, having the minimum reflection loss (RLmin) of −46 dB at 3.6 GHz with the bandwidth of 0.43 GHz (3.38–3.81 GHz) below −10 dB, while a 2.15 mm-thick SrFeZnW (x = 1.0) composite with the Vf of 70% showed the most appropriate for application in the region of 5.9–7.1 GHz, possessing the RLmin value of −23.7 dB at 6.6 GHz with the bandwidth of 1.38 GHz (5.85–7.23 GHz) below −10 dB. Consequently, partially Zn-substituted SrW-type hexaferrites are very promising microwave absorbers for 5G mobile communications in the Ku band (0.5–18 GHz).

A high-performance soft-magnetic composite (SMC) has been successfully fabricated in a toroidal mold without the application of compaction pressure by mixing three different alumina-coated Fe-based metal powders, namely carbonyl iron (FM), Fe-Si-Cr alloy (FSC), and Fe-Si-Al alloy (sendust), with epoxy resin in a centrifugal paste mixer. Surface coating with an alumina layer was performed via a sol–gel process, and its thickness was controlled by varying the coating time. Without the alumina coating, the SMC toroidal core with a FM:FSC:sendust mixing ratio of 8:22:70 by mass exhibited optimal magnetic properties including an effective permeability (μeff) of 33.9 and total core loss (Pt) of 252 mW/cm3 at 100 kHz with an amplitude (B) of 50 mT. With the alumina coating, however, the SMC toroidal core with the same mixing ratio exhibited a significantly reduced Pt value of 213 mW/cm3 while its μeff value was slightly decreased to 32.4, primarily due to the suppression of the macroscopic eddy-current loss from 115 mW/cm3 to 85 mW/cm3. These results indicate that an optimal mixture of the three different alumina-coated Fe-based metal powders is very effective for fabricating high-performance SMC cores without external pressure for molding, being applicable for miniature electronic components.

A novel zwitterionic lithium-benzotriazole sulfobetaine is fabricated by grafting 1,3– propanesultone onto benzotriazole and then lithiating it. The resultant lithium-benzotriazole-sulfobetaine additive is used as an electrolyte additive in lithium ion batteries in 1 M LiPF6 (ethylene carbonate/dimethyl carbonate = 1:1). The electrolytes with the lithium-benzotriazole sulfobetaine shows higher ionic conductivities (2.18 × 10−2 S cm−1) compared to the bare electrolyte (1.07 × 10−2 S cm−1) and greater electrochemical stability (anodic limit at ~5.5 V vs. Li/Li+) than the pure electrolyte (anodic limit at ~4.6 V vs. Li/Li+). The discharge capacity of the lithium cobalt oxide/graphite cells is improved at higher C-rates with the addition of lithium-benzotriazole sulfobetaine due to increased ionic conductivity. The lithium cobalt oxide/graphite cells with the lithium-benzotriazole sulfobetaine additive also show stable cycling performance. These findings warrant the use of lithium-benzotriazole sulfobetaine as an electrolyte additive in lithium ion batteries.

A composite anode material is fabricated from mesoporous carbon and synthesized Li4Ti5O12 nanoflakes for application in lithium ion batteries. Li4Ti5O12 is used as a capacity contributing conductive additive because of the change in its electronic structure from insulating to metallic as it undergoes lithiation. Cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy are used to analyze the electrochemical properties of the mesporous carbon/Li4Ti5O12 nanoflakes composite material, and synergistic results have been confirmed. The composite achieves high specific capacity and excellent cyclability with a capacity stabilizing at 300 mA h g−1 after 100 cycles at a current density of 175 mA g−1 and 200 mA h g−1 after 500 more cycles at a high current density of 500 mA g−1. This research shows the applicability of using LTO as a conducting agent with significant capacity contribution as a composite material with anode materials discharged to 0.01 V for high energy storage with fast charge–discharge capability.

Electrochemical characterization was conducted on poly(vinyl alcohol) (PVA)-ceramic composite (PVA–CC) separators for supercapacitor applications. The PVA–CC separators were fabricated by mixing various ceramic particles including aluminum oxide (Al2O3), silicon dioxide (SiO2), and titanium dioxide (TiO2) into a PVA aqueous solution. These ceramic particles help to create amorphous regions in the crystalline structure of the polymer matrix to increase the ionic conductivity of PVA. Supercapacitors were assembled using PVA–CC separators with symmetric activated carbon electrodes and electrochemical characterization showed enhanced specific capacitance, rate capability, cycle life, and ionic conductivity. Supercapacitors using the PVA–TiO2 composite separator showed particularly good electrochemical performance with a 14.4% specific capacitance increase over supercapacitors using the bare PVA separator after 1000 cycles. With regards to safety, PVA becomes plasticized when immersed in 6 M KOH aqueous solution, thus there was no appreciable loss in tear resistance when the ceramic particles were added to PVA. Thus, the enhanced electrochemical properties can be attained without reduction in safety making the addition of ceramic nanoparticles to PVA separators a cost-effective strategy for increasing the ionic conductivity of separator materials for supercapacitor applications.

Lithium sulfonyl silica (LSS) was synthesized by replacing the surface H group in fumed silica with (CH2)3SO3Li and adopted as electrolyte additive for lithium ion battery. 3 wt% of the synthesized particles in 1 M LiPF6 (EC/DMC = 1:1) showed improved ionic conductivity and better potential stability over the pristine electrolyte. The discharge capacity of the LiCoO2/graphite is particularly enhanced with the addition of LSS at higher C-rates due to the enhanced ionic conductivity at room temperature. The LiCoO2/graphite cells using 1.0 M LiPF6/EC/DMC (1: 1) and 1.0 M LiTFSI/EC/DMC (1: 1) with LSS also showed superior performance for the self-discharge test carried out at 45 °C for 200 days. These positive impacts of LSS on LiCoO2/graphite cells warrant its use in lithium ion batteries.

Supercapacitors provide us with enormous power output for energy storage. Their energy output however still remains quite low compared to other energy storage materials like the batteries. This paper reports a highly stable liquid electrolyte which is composed of mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate(EMIBF 4 ) ionic liquid with highly stable lithium bis(oxalate)borate LiBOB/acetonitrile(ACN). The electrolytes display remarkable supercapacitive performance at a high voltage of 3 V. The electrochemical impedance spectroscopy shows that EMIBF 4 helps to reduce the bulk resistance and charge transfer resistance across the electrode surfaces by facilitating high ionic diffusions across the electrode/electrolyte interface. The high stability and high ionic conductivity of the electrolytes reflected in the good cycling performance tests at 2.8 V with a maximum delivery capacitance of 19.5Fg -1 after 1000cycles at a high scan rate of 200 mVs -1 .

Liquid electrolyte consisting of 1 M LiPF 6 in ethylene carbonate (EC)/dimethyl carbonate (DMC) and 0.1 wt% benzotriazole (BzTz) is studied in LiCoO 2 //graphite battery system at room temperature. Benzotriazole addition introduces excellent electrochemical stability (5.6 V vs Li) and good ionic conductivity properties at room temperature. Also, this electrolyte shows good cycling performance and better discharge capacities at high C-rates relative to the pristine electrolyte. Furthermore, the additive allows the formation of a good solid electrolyte interphase (SEI) per cyclic voltammetry (CV) examination. These specialized properties make this liquid electrolyte ideal for high power and high voltage applications.

We report enhanced electrical properties of metal–insulator–metal (MIM) capacitors consisting of Al (100 nm)/Nb-doped a-HfO2 (∼30 nm)/Pt (100 nm) on a p-type silicon wafer, where Nb-doped amorphous HfO2 (a-HfO2) layers were deposited by radio frequency magnetron sputtering in various low oxygen partial pressures at room temperature. Polycrystalline HfO2 targets with three different Nb contents of 0 mol. %, 6 mol. %, and 10 mol. % were used in this study. Compared with the leakage current of the undoped a-HfO2 film (∼1.1 × 10−8 A cm−2 at 1 V), greatly reduced leakage currents (∼3.7 × 10−10 A cm−2 at 1 V) with no significant alteration in the dielectric constants (∼22) were obtainable from the MIM samples composed of Nb-doped a-HfO2 films, which is attributable to the suppression of oxygen vacancy formation based on the XPS analysis results. The Nb-doped a-HfO2 dielectric thin films also exhibited improved voltage nonlinearity compared to undoped HfO2. These results indicate that Nb-doped a-HfO2 has potential application as a high-κ dielectric material in MIM capacitors.

Zwitterionic lithium-silica sulfobetaine silane is fabricated by first synthesizing zwitterion sulfobetaine silane, grafting it onto hydrophilic silica to form silica sulfobetaine silane, and then lithiating the silica sulfobetaine silane. The resultant lithium-silica sulfobetaine silane additive is used as a liquid electrolyte additive in lithium-ion batteries with varying weight percentages in 1 M LiPF6 (ethylene carbonate/dimethyl carbonate = 1:1). The electrolytes with the lithium-silica sulfobetaine silane shows higher ionic conductivities (1.92 × 10−2 S cm−1 at RT and 1.62 × 10−3 S cm−1 at −20 °C) and greater electrochemical stability (anodic limit at ~5.5 V vs. Li/ Li + ) than the pure electrolyte (anodic limit at ~4.6 V vs. Li/ Li + ). The discharge capacity of the lithium nickel cobalt manganese oxide/graphite cell is improved at higher C-rates with the addition of lithium-silica sulfobetaine silane due to increased ionic conductivity. The lithium nickel cobalt manganese oxide/graphite cells with the lithium-silica sulfobetaine silane additive also show stable cycling performance. These findings warrant the use of lithium-silica sulfobetaine silane as an electrolyte additive in lithium-ion batteries.

Novel magnetic nanocomposite alginate beads are fabricated for the simultaneous removal of cationic, anionic and organic pollutants in highly acidic water. Copper, phosphate and toluene are used as representative cationic, anionic and organic pollutants respectively. The alginate beads were impregnated with a nanocomposite material composed of zeolites, activated carbon, layered double hydroxides and magnetic nanoparticles bound together by xanthan gum. A 3:4:1 aspect ratio (alginate: nanocomposite: xanthan gum) is used for fabrication of the beads. The beads show removal percentage for phosphate at 97.9%, copper at 81.8% and toluene at 43.4% and adsorption capacities of 60.24 mg g –1 , 120.77 mg g –1 and 25.52 mg g –1 respectively. Isothermal studies show that the Langmuir isotherm model is the governing equation for sorption. Pseudo-second-order model is the governing equation for the kinetics of sorption. The sorption process is also spontaneous and exothermic. This sorbent shows great potential to be used for simultaneous removal of cationic, anionic and organic pollutants removal in water.