Nanocoatings Speed up Lithion Ion Batteries

Researchers at MIT, led by Prof. Gerbrand Ceder, have improved the charge (and discharge) rate of lithium ion battery material by a factor of ~30.  The work is reported in Nature and at the MIT website. 

Lithium ion transport is apparently limited by diffusion of lithium ions on the surface of lithium ion phosphate particles to ‘tunnels’ that provide access into/out of the interior of the particles.  The MIT team coated the particles with about 5 nm of a highly conductive (for Li ions) film of phosphate glass, which allows the ions to get to the access tunnels faster.  I reckon that this phosphate glass ‘shunt’ should also serve to decrease the apparent series resistance of the lithium ion batteries at the device level.  As I recall, lithium ion batteries have (today) a nasty tendency to over heat when charged or dicharged rapidly (as in electric vehicles during accelleration or regenerative braking).  This new development is worth watching as it could enable ‘filling station’ recharge rates, and improve the safety and reliability of Li-ion batteries in hybrid and electric vehicles.  Li-ion batteries also have higher energy density than lead-acid batteries, although both are far from the energy density of liquid hydrocarbons.  Still, this might be a good step towards technology useful for store-gen grid components discussed here occasionally.

5nm thick phosphate glass coatings on lithium iron phosphate particles speed up charge/discharge rates by ~30x.