Electrodeposition of aluminum on needle cathode using AlCl3/urea molten salts at low-temperature and its application to hydrogen generation

The electrodeposition of aluminum (Al) was studied using two electrolyte solutions, such as anhydrous AlCl₃-urea and hydrated AlCl₃·6H₂O-urea. A systematic examination using cell voltages 1.0-2.0 V was carried out at temperatures ((50-100)±2) ℃. A needle-shaped cathode was employed for the deposition of aluminum. A dendrite and particulate microstructure of Al were observed on the needle-shaped cathode. An improved condition for the manufacturing of small sizes and high purity of aluminum deposits was obtained. Pure Al with a current efficiency (yield) of 84%-99% was obtained from those of non-aqueous electrolytes and only of 8.6%-9.3% from those of hydrated electrolytes. The electrical conductivities of electrolytes remained considerable at ((50-100)±2) ℃. The improved aluminum powders were used for the reaction with water. The aluminum reacts with water at room temperature, producing pure H₂ with 100% yield. The electrodeposited aluminum metal can be used as an excellent energy carrier.