Micro-recycling of spent Ni-Cd batteries for the obtention of electrocatalytic coatings

A micro-recycling approach was explored to produce catalytic metallic coatings for the hydrogen evolution reaction (HER). For this aim, discarded Ni-Cd batteries were employed as raw material. After dismantling the batteries, the active powder material, containing Cd and Ni compounds, was leached in a solution containing citric acid and hydrogen peroxide. The dissolved metals were electro-deposited on copper plates using a two electrodes cell at the following potentials (mV): -1900, -2000, and -2100 mV. The CdNi coating produced at -2000 mV, contained 92.6 % Cd and 7.4 % Ni. This coating was studied by cyclic voltammetry (CV) and potentiodynamic analysis in two different KOH solutions (0.1 M and 1.0 M). The CV analysis showed that the CdNi electrode was electrochemically stable in a wide operating voltage range (between oxygen evolution reaction and HER). Using an uncompensated resistance correction, the Tafel slopes for HER were obtained. The potentiodynamic analysis revealed that the synthesized CdNi electrode showed a catalytic activity for HER just 25.5 % smaller than the correspondent response of a standard pure Ni electrode. Our results serve as a proof of concept about the application of micro-recycling of spent batteries to produce sustainable electroactive catalytic materials for hydrogen production.

Flat UWB antenna with optimized ground plate

The design of a broadband antenna based on a combination of electric and magnetic emitters is proposed. Antenna size ratios are proposed that provide a wide operating frequency band. The results of numerical modeling of the standing wave ratio and radiation patterns for a particular case with a matching range from 13 GHz to 27 GHz are presented.

Generating Innovative Solid Polymer Electrolyte Based on Melanin and Without Binder for High Energy Li Batteries

The goal of this investigation is connected with wishes to use the melanin for formulating the solid polymer electrolyte without the binder for Li batteries. Nature and properties of solid polymer electrolyte of the Li batteries is an important factor for ensuring the properties of Li batteries. For successful optimization the properties of Li batteries the following list includes the important requirements for the polymer electrolyte: high conductivity in wide operating temperature, chemical stability and no ignition at under high temperature - even more than 1000C, low impedance of interface between electrode and solid polymer electrolyte, special design of system - the solid polymer electrolyte in porous structure of electrode. For developing the solid polymer electrolyte without the binder we fulfill this goal includes the melanin in the solid polymer electrolyte.