Li-Ion With 300% More Power, Minutes to Recharge

Battery Nut writes "Altair Nanotechnologies claims to have found a way to reduce Li-Ion recharge time to minutes, as well as increase battery power by 300%, according to this press release. Seems they have received some good feedback by certain experts about thier work: "Two eminent experts in battery technology, Dr. K. M. Abraham and Dr. Vassilis G. Keramidas, have expressed strong support for Altair's work. " So is it a new revolution in battery technology, or hopeful hype? Stay tuned, their quarterly conference call is Thursday Feb 24th at 11AM." Anyone else think snake oil?

Comments

Seems almost reasonable

[Anonymous Coward]

According to the article, they use a Lithium titanium oxide nanomaterial. Best gues, the nanocrystals typically have little or no stress and a low defect density, as well as an extremely high surface to volume ratio. All of these should improve the efficiency and speed of the battery operation. This might also increase the speed that the battery can discharge. Of course, I am not a battery specialist. Just in nanomaterials development. Might not be snake oil. Assuming all the accolades are true... well, Altair doesn't have a reputation for falsifying data. I look forward to seeing this develop.

Re:Seems almost reasonable

[Alceste]

That's actually not true. Nanometer sized crystals have large surface to volume ratios than bulk crystals, creating more surface defects per unit mass. The defects within a bulk crystal can be annealed to an equilibrium number, the same as those in a nano-crystal per unit mass. Thus, since battery performance is based on unit mass, you need the name weight of nano-crystals or bulk crystals to get the same capacity (to an order of magnitude, some papers show that surface defects actually INCREASE capacity, nifty stuff).

In addition, Li(z)Ti(x)O(y) is a system that undergoes phase changes during Lithium intercalation and deintercalation (as the battery discharges the "z" goes from 1 to 0). So the crystals are being made a-new with each charge discharge cycle (increasing cycle life, but this is something that also happens in the bulk, no need for nano whatnot).

Interestingly, the energy/power density with lithium titanium oxides is actually lower than that for carbons. A battery with a lithium cobalt oxide cathode and a lithium graphite anode will have a maximum potential of 4.2 V. The battery in question in the article actually sits around 3.0 V.

Finally, the failure mechanism for lithium ion batteries is not the anode, but the area just outside the anode called the SEI layer. This is a passivation layer formed adjacent to the anode by reaction of the neutral lithium with the organic electrolyte. This layer forms initially by irreversibly consuming some lithium, but if the charge/discharge rate is moderate it becomes stable and actually protects the anode. If the charge/discharge is too high, though, the layer breaks and more lithium is consumed to repair it, thus diminishing capacity. After enough of these cycles the batter will dramatically lose capacity.

Thus, the breakthrough in question must deal with a way of maintaining a stronger SEI layer, but it is most definitely at the cost of a lower potential battery.

Re:Hard hat required

[pong]

My laptop battery has a voltage rating of 10.8. The amount of energy in Joules on a battery with a voltage of 10.8V and power rating of 12Ah, would be

E = 10.8V * 12Ah = 129.6Wh = 467 KJ (3600 J/Wh)

E = P * t, so P = E / t

P = 467 KJ / (5 * 60) secs = 1555W

1555W is less than many hair driers

3x max current, not capacity

[fhage]

According to http://www.evworld.com/view.cfm?section=communique &newsid=7681 "The nanomaterials Altair is developing are the next generation of electrode materials for lithium-ion batteries and Altair's research and product development is laying the ground work for a new generation of ultra high power lithium ion batteries," commented Dr. K. M. Abraham. "A key requirement to the above applications is the ability to recharge the battery very quickly, for example in a few minutes. Current Li Ion batteries are incapable of such quick charge times because of the chemistry of the anode materials. Altair has found a solution to this with their nano-sized lithium titanium oxide."

Current Li batteries are very limited in their max current. This make them poor choices for high current applications, like electric motors. It won't make your laptop run any longer, but you'll be able to charge it 3x faster.

Is it really 3 times the power?

[grahamsz]

If so then it's only going to allow power to flow out of the battery 3 times faster, allowing a whole new generation of power-hungry athalon laptops (at 1/3rd of the current battery life)

However if it were 3 times the ENERGY then it'd make existing laptops run for 3 times longer.

Re:Snakeoil?

[tlhIngan]

Current lithium batteries are slow to recharge because they have a high internal resistance, and low tolerance for overvoltage. A typical battery cell with 3.6V idle voltage takes no more than 4.3V when charging, and the .7V drop over the internal resistance allows very little current through the battery, which is why it takes 3hr to recharge fully.

Actually, LiIon has a low internal resistance - it's somewhere between that of NiCd and NiMH chemistries (when new). However, as it ages (i.e., the moment it leaves the factory), the internal resistance gets higher and higher until it can no longer usefully power the load (generally 2-5 years after manufacture).

The reason LiIon is slow to charge is because it requires a complex charge regimen. Plus you can't trickle charge them (destroys them). So you charge them at a constant current up around 90% or so, then switch to constant voltage until the cell stops accepting charge. Then you stop and switch off the charger until it drains to around 95% (estimated), and do a CV charge again.

The end result is you get around 90% charge very quickly, but the last 10% take forever as the charger puts in less and less current.

Charge it incorrectly and they go boom.