Lithium Polysulfidophosphates - solid state battery

[trex]

From I think this may be the revolutionary battery technology we have been waiting for - Page 2 - JREF Forum

Li3PS4 was prepared by a procedure described previously.[14] The sulfur compounds Li3PS4+n (n=2,3,5,6, and 8) were synthesized through solution reactions of Li3PS4 and elemental sulfur in tetrahydrofuran (THF) under magnetic stirring without exposure to air or moisture. After the solids were fully dissolved, the solution was dried under vacuum for 2 h at 80C. The recovered solids were lithium polysulfidophosphates. The cathode slurry was prepared by dispersing Li3PS4+5 (60 wt%), WVA-1500 carbon (MeadWestvaco Corporation, 30 wt%), and PVC binder (10 wt%) in THF. No side reaction occurred to the binder during the preparation of electrode because of the rapid evaporation of solvent.[15] A solid electrolyte pellet of Li3PS4 with a lithium metal anode was prepared by coldpressing nanoporous b-Li3PS4 (120 mg) on top of a thin lithium foil (50 micron thick) under 240 MPa pressure in a 13 mm die. The slurry was then coated on the other side of the pellet and dried under vacuum at 80C. The loading of the cathode materials is 0.25–0.60 mgcm2, which is equivalent to 0.15–0.36 mAhcm2. The final thickness of the pellets was 0.5 mm.

The amazing ionic conductivity of PSP makes possible elimination of liquid electrolyte, resulting in thinner, lighter cells and better gravimetric energy density. The researchers reckon they can get 4 to 8 times the power storage density of current Lithium iron phosphate batteries.
It does look very promissing. Well understood chemistry, cheap and easy to make (for Chinese companies) - It won't be long before your average battery (36V 15AH) weighs less than 1kg and costs under £100.

 

[Taff]

But I want it now!

 

[jazper53]

What about the discharge rates is it comparable or better, can't tell from JREF forum babble.

 

[trex]

I have no idea. PSP is Lithium based chemistry, so it should be similar to what we have now.
I assume that without the liquid, the battery can run much hotter than now, enabling higher charge/discharge current.
It will also eliminate the main cause of damage to present e-bike batteries.
At present, the electrolyte can react with the free Lithium, causing soft pouch cells to swell, making the cells very vulnerable to shocks.

 

[Deleted member 4366]

Oxis were touting them at the NEC bike show. Wisper were in collaboration with them at the time, but all seems to have gone quiet since. IIRC the discharge rate was rather low, so you'd need a larger (physical size) battery to get a decent output, which is even worse now that 18 to 20 amps is becoming more common.

Oxis Energy

 

[trex]

Oxis uses liquid electrolyte, that's why it got them nowhere.
The key step is to replace the liquid electrolyte with a sulphur rich solid, like sound wave, electrons traverse solid lattice at much higher speed than liquid/solid interphase, resulting in at least an order of magnitude lower internal resistance. Just think of the thermo-couples.

 

[Scimitar]

I look forward to LPSP sweeping the board - but I'm not holding my breath.

 

[mountainsport]

Under £100 I don't think so, you'll be paying much more for the new and improved technology . Then the more people buy it, the more the price goes up.

MS.

 

[trex]

the only new technology is to optimize polysulphidophosphates formulation, it's already proven to be working and the fabrication side has about the same degree of difficulty as with current batteries and I don't think anyone could claim royalty on the use of LiPSP as electrodes.
It could be that more people buying it will make it cheaper.

from http://www.greencarcongress.com/2013/01/cui-20130109.html

It basically worked the first time we tried it. The sulfur cathode stored up to five times more energy per sulfur weight than today’s commercial materials.

After 1,000 charge/discharge cycles, our yolk-shell sulfur cathode had retained about 70 percent of its energy-storage capacity. This is the highest performing sulfur cathode in the world, as far as we know. Even without optimizing the design, this cathode cycle life is already on par with commercial performance. This is a very important achievement for the future of rechargeable batteries.
—Yi Cui

 

[Eaglerider]

Splendid.

If it's true, then I can get a 50+ A/H battery and climb the French Alps all day long on one charge. I definitely want one!

 

[flecc]

I wouldn't bet on getting these, but would happily bet on us not getting them.

Such is the nature of new battery technology announcements that the latter bets are very safe ones!

 

[Deleted member 4366]

I have to admit that you've always been right on these things, Flecc. I''ve been guilty of swallowing the salesman's horse-feathers myself Always hoping though.

 

[flecc]

I would like nothing more than to be wrong one day on one of these announcements Dave, but only cold fusion research announcements breed cynicism better than that of batteries.

My down-to-earth measure of success will be when one of the major car companies fit a new lighter type in place of lead-acid.