Nanotech Makes Safer Lithium Batteries

Lithium-ion batteries typically contain two electrodes and an electrolyte. Shorting or overcharging the battery makes it generate heat. If the temperature reaches about 300 degrees Fahrenheit (150 degrees Celsius), the electrolyte can catch fire and explode.

spikesThere have been several attempts to make safer lithium-ion cells, but often these safety measures render them unusable after overheating. Stanford University researchers have a new method to protect from overheating cells that uses–what else–nanotechnology graphene. The trick is a thin film of polyethylene that contains tiny nickel spikes coated with graphene (see electron micrograph to the right).

The film conducts electricity from one electrode because the nickel spikes touch each other at normal temperatures. If the cell overheats, the polyethylene film expands, and the spikes no longer touch each other, breaking the circuit. Once the cell cools, the film contracts, the nickel spikes make contact again, and the cell resumes normal operation.

We’ve seen a lot of battery research lately, ranging from lithium-air cells to sodium-ion batteries. We can’t wait until we can power our phone for a year on a single charge.

11 thoughts on “Nanotech Makes Safer Lithium Batteries

  1. This is pointless, in a battery with sol-gel electrolytes there is no need for thermal protection. With the right separator and electrolyte performance can actually be enhanced at high temperature.

    Thanks anyway this could be very useful for a different application, as with most things developed in academia.

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