http://edge.rit.edu/edge/P13656/public/Phase_II_Documents/Luigi/Redox%20Reactions/Electrochemical%2BOxidation%2BBehavior%2Bof%2BTitanium%2BNitride%2BBased%2BElectrocatalysts%2BUnder%2BPEM%2BFuel%2BCell%2BConditions.pdf

Electrochemical oxidation behavior of titanium nitride based electrocatalysts under PEM fuel cell conditions

Ultrahigh rates realized by ALD-made TiN. The symmetric full-cell supercapacitors deliver a typical capacitance of 20.7 F cm-3 at a scan rate of 1 V s-1, and retain 4.3 F cm-3 at high rate of 100 V s-1. The devices can be charged and discharged for 20 000 cycles with negligible capacitance loss and with an ultralow self-discharge current (≈1 μA).

https://dr.ntu.edu.sg/bitstream/10356/85007/1/Ultrafast-charging%20supercapacitors%20based%20on%20corn-like%20titanium%20nitride%20nanostructures.pdf

Ultrafast‐Charging Supercapacitors Based on Corn‐Like Titanium Nitride Nanostructures

On the stability of TiN-based electrocatalysts for fuel cell applications

Recently, dielectric capacitors have drawn much attention from researchers and engineers due to their ultrahigh power density, ultrafast charge–discharge rate, and good temperature and fatigue stability. However, most related research mainly focuses on the improvement in dielectric breakdown strength and energy storage density rather than that in energy efficiency. In this study, we adopted the spark plasma sintering method to modify the microstructure and electric conductivity of Na0.7Bi0.1NbO3 lead-free ceramics, and subsequently enhanced their energy storage properties. As a result, the Na0.7Bi0.1NbO3 ceramics prepared by the spark plasma sintering method display a considerably large energy storage density of 3.41 J cm−3 with an ultrahigh energy storage efficiency of 90.8% at 28 kV mm−1. The improvement of energy storage performance is ascribed to the reduction of electric conductivity, which can be analyzed by the X-ray photoelectron spectroscopy and high-temperature complex impedance spectra. This study not only paves the way for environment-friendly Na0.7Bi0.1NbO3 lead-free ceramics to be developed for energy storage applications, but also interprets the internal mechanism of microstructure modulation which enhances energy storage properties.

Achieving ultrahigh energy storage density and energy efficiency simultaneously in sodium niobate-based lead-free dielectric capacitors via microstructure modulation

Hydrothermal synthesis of sodium potassium niobate solid solutions at 200 °C

Scanning magnetron-sputtered titanium nitride (TiN) films were deposited onto silicon substrates under varying nitrogen and argon pressures. Golden TiN films with (220) orientation were deposited at different substrate bias voltages (0to−120V). Auger electron spectroscopy measurements show N∕Ti ratio between 1.18 and 1.07, and oxygen content between 11% and 5% in the as-deposited TiN film samples. Dependence of the stress and grain size on substrate bias voltage and dependence of resistivity on bias voltage and annealing temperature have been studied for the deposited TiN films. Resistivity was found minimum for the TiN samples deposited at −40V bias, which decreases from 320to132μΩcm on annealing, up to 750°C. Copper was sputter deposited on the as-grown TiN films deposited at −40V bias. The Cu∕TiN∕Si samples were annealed at different temperatures. Resistivity, x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray analysis results of the Cu∕TiN∕Si structure are consistent with eac...

Scanning magnetron-sputtered TiN coating as diffusion barrier for silicon devices

Ceramic pellets of different compositions of Na 1−xKxNbO 3 system (x = 0 to 0.5) have been prepared using ‘solid-state reaction’ method. Pellets of 6 mm diameter have been prepared under two conditions; first, the calcined mixtures were pressed at 0.2 MPa and sintered in a tube furnace opened at both ends; and second, the calcined mixtures were pressed at 0.02 MPa and sintered in a closed furnace. Prepared samples were characterized by x-ray diffraction (XRD) and energy dispersive x-ray analysis (EDAX) method. In the XRD pattern, a continuous shifting of most intense peak (002) to lower angle was observed with increasing potassium concentration (x), except for x = 0.5, where a break in the peak shifting pattern was observed. Lattice parameters and crystallite size for different compositions have been calculated from the XRD data. EDAX results show marked sodium deficiency in the prepared samples. Frequency and x dependence of dielectric constant, loss tangent and dielectric conductivity have been investig...

Morphotropic Phase Transitions in Mixed Sodium-Potassium Niobate System

Morphotropic phase boundary in Na1−xKxNbO3, near x=0.32

Using solid state reaction method, ceramic pellets of NaNbO 3 , Na 06 K 04 NbO 3 and Na 05 K 05 NbO 3 have been prepared Temperature and frequency dependence of dielectric constant and loss tangent of the prepared samples have been studied It has been observed that, at the transition temperature, dielectric constant peak shifts to lower temperature, and the dielectric constant and loss tangent peak heights decrease, with increasing frequency; which shows the relaxational behavior of this system

Relaxational behavior of mixed NaNbO3-KNbO3 system

The electrical conductivity of barium titanate and 0.4% (mole) La doped barium titanate ceramics have been measured in the temperature range from 30 to 170°C with the help of a pA-meter at 10–90 V d.c. It is observed that doped ceramics give better positive temperature coefficient of resistivity (PTCR) effect than the undoped ceramics and by increasing voltage the PTCR region contracts for both types of the samples. The electrical conductivity at room temperature has also been measured using ramp and staircase voltages. It has been observed that by doping the room temperature electrical conductivity increases markedly by the order of 105. The electrical conductivity at room temperature of doped and undoped samples is larger and increases faster with voltage for the applied staircase voltages than that for the ramp voltages.

N. S. Panwar

Papers

Scanning magnetron-sputtered TiN coating as diffusion barrier for silicon devices

Morphotropic Phase Transitions in Mixed Sodium-Potassium Niobate System

Morphotropic phase boundary in Na1−xKxNbO3, near x=0.32

Relaxational behavior of mixed NaNbO3-KNbO3 system

Study of electrical conductivity of barium titanate ceramics