Spinel cathode materials consisting of LiMn2 O4 @LiNi0.5 Mn1.5 O4 hollow microspheres have been synthesized by a facile solution-phase coating and subsequent solid-phase lithiation route in an atmosphere of air. When used as the cathode of lithium-ion batteries, the double-shell LiMn2 O4 @LiNi0.5 Mn1.5 O4 hollow microspheres thus obtained show a high specific capacity of 120 mA h g(-1) at 1 C r...

A theory for the single-channel hollow cathode (SCHC) that includes the relevant physical processes and predicts the operating parameters is presented. A SCHC consists of a cylindrical channel approximately ten diameters in length through which a working gas (taken as lithium vapor here) flows and exits as a plasma. A high current (1-100 A) is conducted into the channel by the plasma and to the...

We report on a kinetic model that computes the electron behaviour in a hollow cathode discharge. It is a part of the PLASIMO toolkit and is based on a Monte-Carlo technique. The model is tested by varying the input parameters and by comparing the output with the output obtained by the freeware Boltzmann equation solver BOLSIG+. The results show that the Monte-Carlo model gives reliable informat...

An experimental investigation of the operating characteristics of 3.2 mm diameter orificed hollow cathodes was conducted to examine low-current and low flow rate operation. Cathode power was minimized with low orifice aspect ratio and the use of an enclosed keeper. Cathode flow rate requirements were proportional to orifice diameter and the inverse of the orifice length. Cathode temperature pro...

The low pressure glow discharges considered in this paper are the hollow cathode (Paschen), and the flat cathode (Grimm). Both discharges have similar voltage—current characteristics which are responsible for their radiation stability. The analytical sample is supplied to the discharge through a sputtering mechanism which provides a stable and non-selective source of particles. Some of the fund...

A method is described for mapping the plasma parameters nearby a hollow cathode using a high speed positioning system and a segment-shielded electrostatic probe. Contour maps of plasma density, plasma potential, and electron temperature are presented for wide ranges of discharge current (2 20 A) and xenon flow rate (1.5 – 4.5 sccm). The contour maps are constructed from the analysis of 320 I-V ...

We present an experimental comparison of parallel plate and hollow cathode microplasma structures, operated at high pressure with narrow anode–cathode gaps. A moveable anode arrangement with ±12μm spatial resolution was used to vary the electrode separation to cover the pd range between 0.01 and 4 Torr cm for both structures. The hollow cathode discharge was operated with pressure–diameter (pD)...

Data are presented on cathode temperature profiles, electron emission profiles under no-flow conditions, and timed starting tests with gas flow. Correlations between the temporal behavior of the noflow emission current and the starting time are made, and a model is presented of the barium/bariumoxide generation and surface diffusion processes that describe the electron emission profile and star...

Since 2006, we have been developing a novel photocathode gun gated by the laser-induced Schottkyeffect. This new type of gun utilizes laser coherency to aim at a compact femtosecond laser oscillator as an IR laser source using Z-polarization on a metal photocathode. This Z-polarization scheme reduces the laser photon energy to excite the cathode with a longer wavelength by reducing its work fun...