But what does that mean? The simple answer is how heavy something is for its size. If something seems very heavy for its size (like a heavy metal object), we say it is more dense. If something seems ...

WeLion, a Chinese developer of solid-state batteries, is making good progress toward achieving a long-term energy density of 1,000 Wh/kg. In the lab, the ...

ALBUQUERQUE, N.M. — Scientists have come up with ways to squeeze hydrogen molecules to pressures approaching a million times the atmospheric pressure we experience on Earth’s surface. Such ...