For centuries, useful metals have been developed by starting with one core element and adding small amounts of other elements. Steel, for example, is composed primarily of iron; carbon is added in varied amounts to produce different grades of steel. Bronze is made up of copper and tin. These mixtures are known as alloys.

Storing hydrogen in metallic materials is a promising avenue for extracting value from Africa’s minerals.

For centuries, useful metals have been developed by starting with one core element and adding small amounts of other elements. Steel, for example, is composed primarily of iron;…