Category Technology/Electronics

Stanford researchers are using spiky nanoparticles of graphene-coated nickel to create a lithium-ion battery that shuts down when it’s too hot, then quickly restarts when it cools (1µ =1 micrometer). Credit: Zheng Chen, Stanford University

The new technology could prevent the kind of fires that have prompted recalls and bans on a wide range of battery-powered devices, from recliners and computers to navigation systems and hoverboards. “People have tried different strategies to solve the problem of accidental fires in lithium-ion batteries,” said Prof. Zhenan Bao, chemical engineering, Stanford. It “can be shut down and revived over repeated heating and cooling cycles without compromising performance.”

A typical Li-ion battery consists of 2 electrodes and a liquid or gel electrolyte that c...

a) Coated rods are arranged along a sub­strate, like angled teeth on a comb. b) The teeth are then inter­laced. c) When indium and galium come into con­tact, they form a liquid. d) The metal core of the rods turns that liquid into a solid. The resulting glue pro­vides the strength and thermal/​electrical con­duc­tance of a metal bond. From “Advanced Mate­rials & Processes,” Jan­uary 2016

Experts in nanotechnology have developed a glue that binds metal to metal to glass to you-name-it, sets at room temp, and requires little pressure to seal. “MesoGlue was founded by Huang and two of his PhD stu­dents: They had a dream of a better way of sticking things together...

Light from an optical fiber illuminates the metasurface, is scattered in four different directions, and the intensities are measured by the four detectors. From this measurement the state of polarization of light is detected. Credit: Capasso Lab/Harvard SEAS

What do astrophysics, telecommunications and pharmacology have in common? Each of these fields relies on polarimeters – instruments that detect the direction of the oscillation of electromagnetic waves, ie polarization of light.

When light is reflected or scattered off an object, its polarization changes and measuring that change reveals a lot of information. Astrophysicists, for example, use polarization measurements to analyze the surface of distant, or to map the giant magnetic fields spanning our galaxy...

Secretion in droplet-embedded gel permits self-repairing behavior. Three-dimensional confocal fluorescence images show damaged gel (top) after 0.5 hours and the self-repaired gel after 72 hours (bottom). Credit: Image courtesy of Joanna Aizenberg

Inspired by healing wounds in skin, a new approach protects and heals surfaces using a fluid secretion process. In response to damage, dispersed liquid-storage droplets are controllably secreted. The stored liquid replenishes the surface and completes the repair of the polymer in seconds to hours.

The fluid secretion approach to repair the material has also been demonstrated in fibers and microbeads...