As tensions mount between China and the United States, automakers in the West are trying to reduce their reliance on a key driver of the electric vehicle revolution - permanent magnets, sometimes smaller than a pack of cards, that power electric engines.

Most are made of rare earth metals from China.

The metals in the magnets are actually abundant, but can be dirty and difficult to produce. China has grown to dominate production, and with demand for the magnets on the rise for all forms of renewable energy, analysts say a genuine shortage may lie ahead...