Sunday, December 30, 2007

Silicon nanowires boosts Li-ion batteries

Interesting article on Silicon nanowires as lithium intercalation medium for Li-ion battery anode. Claims to be able to hold 10-times the amount of lithium.

Monday, November 5, 2007

MIT's Department of Materials Science explores the Frontiers of Energy Storage Materials...

This Friday, Nov 9, 11-2PM in 35-225, the MIT Department of Materials Science & Engineering will host the first event in its "Frontiers of Materials Science" syposium series:

Materials for Energy: Materials Challenges, New Developments, and Potential Solutions to the Energy Problem

11AM: Ernie Moniz, head of the MIT Energy Initiative will set the stage for the broader energy problem

11:30AM: DMSE Prof Gerd Ceder, battery materials expert and world leader in using computational techniques to discover novel high performance battery materials, will speak about the opportunities that exist in developing new materials to help solve the materials challenge - one can only imagine that he will talk about 1.) batteries, 2.) fuel cells, 3.) hydrogen storage, 4.) thermoelectrics, and 5.) catalysts??

12:15PM: DMSE Prof Yet-Ming Chiang, technology founder of A123 Systems, will speak about the opportunity that new developments in battery materials hold for finally enabling an electric vehicle revolution. (His company is working very closely with GM as it develops the first mass manufactured plug-in hybrid vehicle, the Chevy Volt).

1:00PM: Northeastern Prof Sanjeev Mukerjee will, I believe, be speaking about the latest development in PEM fuel cells.....

Should be a great event!

More doubts about EEStor....

More doubts coming out all the time about the legitimacy of EEStor's solid state capacitor technology....

Thursday, October 4, 2007

Battery Discussion Follow-up: A Battery Revolution?

Thanks to everyone who attended/participated in the recent Battery Discussion ('A Battery Revolution?', Oct 3, '07). There was a ton of participation for a diverse number of people with great backgrounds/perspectives.

I've been requested to follow up the discussion with this blog to encourage continued discussion on this topic. I'll first summarize some of what we talked about, then try to stimulate more discussion.

I've uploaded a slideshow and the handout I put together for the discussion:


-Batteries are appealing because they have a low enough cost, long lifespan, are very reliable, and have enough power-to-energy suitable for most portable applications. Batteries were really enabled by portable applications - otherwise, electronic devices can simply run off of grid power, or generator power.

-Fuel cells have higher energy/power density that batteries, but their round-trip efficiency is ~35%, compared to >90% for Li-ion batteries, and they are more expensive.

-Neither batteries nor fuel cells, in of themselves, are 'renewable energy sources', but rather, they could play a role in the energy infrastructure, enabling renewable energy sources (like wind, solar, hydro, nuclear (?)) to charge the batteries/create hydrogen, which in turn, could power our cars. This could break the CO2 cycle and reduce dependence on foreign oil.

-Flywheels and capacitors can supply a lot of power, but do not have good energy density (or cost per unit energy, $/kWh).

-There is a company in Texas (EESTOR) making some pretty revolutionary claims about new ultracapacitors with higher 'energy' density that lithium-ion batteries (not to mention, longer lifespan, lower cost, and high power density). I would be very excited if this becomes a reality, but I am skeptical until I see a working model.

-There was much discussion about the use of batteries in hybrid electric vehicles (HEV's) /plug-in (PHEV's). Batteries are certainly pushing towards these markets, but they have more challenges to overcome, including safety, cost, and energy density.

-Lastly, the talk shifted towards other applications, such as renewable energy (i.e. wind power) support. Such a storage device must cost ~$100/kWh, have moderate efficiency (>70%), and very long lifespan (>3000 deep cycles). It's a very tough market to enter, but if a battery can do it, it's a 'game changer'. Some utilities in the US are already installing sodium-sulfur (NAS) or flow batteries (Premium Power) for this (and other) grid power applications. The cost of the NAS battery alone is ~$170/kWh, vs. $100/kWh for lead-acid batteries (which don't have the cycle-life required for these applications), vs. $1000/kWh for Li-ion batteries.


There were a couple of areas that we touched upon but didn't have any good answers to. I'd like to finish this post by posing the following questions:

1) What makes up the cost of a battery? I've heard that ~30% is materials related - but what are the other cost components? (i.e. manufacturing, transportation, labor, disposal of toxic chemicals?)

2) Is there a "Moore's Law" equivalent for batteries? How has the cost/energy density/power density improved over time?


Thursday, August 16, 2007

A123 signs direct co-development deal with GM for Volt Plug-In

A123 Systems, a Watertown, MA MIT battery start-up spun out of Materials Science Prof. Yet-Ming Chiang's lab, has signed a direct co-development deal with GM to develop batteries for the GM Chevy Volt. Previously, A123's interaction with GM on the project was through Germany's Continental Automotive Systems as a sub-contractor. (See great Tech Review article by Kevin Bullis on this here.)

The new direct relationship appears to indicate a greater belief of GM in A123's technology.

However, A123 has not yet wrapped up the GM Volt battery deal, as there is still one other battery supplier in the hunt alongside it. The other player is Compact Power (Troy, Michigan), a subsidiary of South Korean conglomerate LG Chem.

Interestingly, it appears to be a contest between LiFePO4 cathodes (A123) and LiCoO2 cathodes (Compact Power). LiFePO4 offers much higher safety in that it does not undergo thermal runaway (i.e. heat it up and it won't break down into more reactive components making more heat....) but has a lower energy density than LiCoO2.

Who will win and why?? Weigh in!!