Natural Science Forum / Chemistry / Electrochemistry / July 2008

I don't know about better energy density, but I'm keeping an eye on
improved conventional technologies if only because they'll likely be
more affordable:

http://www.fireflyenergy.com/

This is just an improved lead-acid battery and it might just be good
enough for short-medium range electric vehicles and deep hybrids.

Molten sodium-sulfur batteries and similar types have high energy
densities but haven't shown themselves to be practical, yet.  Lithium
keeps looking for breakthroughs that will depend on manufacturing
technologies yet to be demonstrated.  I'm not expecting any major
developments in the near future, just incremental improvements.

--Damon

Considering that Li is the lightest of the energetic metals,
and has good kinetics to move around, it will stay the
main metal used in high-energy batteries.

So new big thing will still be a better Li-ion battery.

On cathode side I like LiFePO4 cathodes. It is much safer (no thermal
run-away)
Potentially cheap (no expensive metals like Co or Ni)
Non toxic.
Very durable (2000 cycles and more)
Downside - less energy.

Some similar phosphate material that can eliminate energy downside
by going to higher voltage and having higher specific energy
would be the killer.

Some people also believe that cathodes using non-ionic conductors
which completely dissolve during reaction rather than maintaining
their crystalline structure will be next big thing because of
tremendous theoretical energy density. Examples are sulfur cathode
or LiF cathode.
Problems with kinetics and fast degradation so far did not allow to
realize the energy
density promise.

On anode side, improvements will include moving to Si or its alloys.
Cycle ability is a problem with Si but some improvements have been
made recently
by using "flexible" (paper-like) binders which eliminate particle
disconnection
from each other.

Li-metal anode is not likely specially with present increased focus on
safety.

Regards,
Yevgen