Experimental researches on hydrogen generation by aluminum with adding lithium at high temperature

• The Al–H2O reaction with Li addition in molten state was researched.
• Li addition can achieve a great promotion of H2 yield and H2 generation rate.
• The Al–20%Li case achieved a H2 yield of 88%.
• With Li addition, LiAlO2 was detected in the reaction products.
• XRD and TEM-EDS results indicated the promoting mechanism of Li.

In order to recover the released heat of Al–H2O reaction and promote the reaction itself, the hydrogen production processes of aluminum with lithium addition in molten state are investigated. Experiments are conducted by both a thermogravimetric analyzer and a special experimental facility at high temperature. The results on both apparatuses show that the addition of Li can promote the reactivity of aluminum with water. Compared with pure aluminum, only 5% of Li content can achieve a great improvement: the H2 yield increases from 8.7% to 53% and the average H2 generation rate from 15 to 112 mL min−1 g−1. With the increase of Li content, H2 yield is improved distinctly and the period with a high H2 generation rate is prolonged. In the Al–20%Li case, the H2 yield of 88% is obtained, and it appears a stable period in which the H2 generation rate keeps high. When adding lithium, LiAlO2 appears in the products and the products are made of columnar crystals. The pores with an average size of 17–33 nm in the LiAlO2 products are manyfold bigger than the pores of alumina, which takes an important role in improving the reactivity of aluminum and water.