80-year-old mystery in static electricity finally solved

Historically, contact electrification (CE) was humanity’s first and only source of electricity up until around the 18th century, yet its true nature is still elusive. Today it is considered a core component of technologies such as laser printers, LCD production processes, electrostatic painting, and separation of plastics for recycling as well as a major industrial hazard (damage to electronic systems, explosions in coal mines, fires in chemical plants, etc.) due to electrostatic discharges (ESD) accompanying CE. In a vacuum, ESDs of a simple adhesive tape are so powerful that they generate enough X-rays to take an X-ray image of a finger.