Thread for new battery breakthrough PR releases

BlueSwordM said:
The funny thing about silicon anodes is that pure silicon particles tend to expand and crack when lithiated (getting lithium ions into its structure), resulting in the passivation layer (the SEI layer, or Solid Electrolyte Interphase layer) getting broken down and exposing fresh lithium; this consumes electrolyte and precious lithium from the surrounding lithium salt. This happens over a few tens of cycles until the cell just dies.

Something similar seems to happen with anode-free lithium metal anode designs, where LiFSI is getting consumed, degrading the electrolyte, but some smart people seem to have discovered why this happens and gave us smol people an outlook on where to look next:
www.nature.com

Application-driven design of non-aqueous electrolyte solutions through quantification of interfacial reactions in lithium metal batteries - Nature Nanotechnology

Tailored non-aqueous electrolyte solutions are formulated using data obtained from extensive analytical measurements and analyses. These optimized electrolytes improve the cycling performance of single-layer stack lithium metal pouch cells, particularly in lean electrolyte conditions.
www.nature.com www.nature.com

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Wait a minute.

I just noticed a few of authors come from CATL lmao.
 
I've been waiting for the full paper to come out, and I'm happy to be able to finally share it:

As long as you don't continuously cycle a lithium-ion cell, that contains either graphite or any amount of silicon, a lower storage percentage, or State of Charge (SOC), is always better for long term storage because it both reduces self-discharge considerably and greatly extends calendar life

For your cells/unassembled batteries, my recommendations would be:

-> For emergencies, obviously keep a few cells at 90-100%; your safety is more important than anything else.
-> Store at 80% if you plan to use your cells occasionally, like most of my flashlights
-> Store at 10-20% SOC (around 3-3.2V) for mid-long term storage
-> 0-10% SOC (2.6-3V) if you store long term and periodically check their voltage.

For assembled battery packs:

-> Store at 30% for long term storage while periodically checking pack charge; this is true for any packs that use lithium ion cells, particularly those with any amount of silicon in their anode.
-> Avoid keeping your battery packs fully charged if you don't use them immediately. Immediate usage at 100% is better for long term life, so take advantage of things like adaptive charging/timed charging/Just In Time storage.
 
BlueSwordM said:
I've been waiting for the full paper to come out, and I'm happy to be able to finally share it:

For your cells/unassembled batteries, my recommendations would be:

-> For emergencies, obviously keep a few cells at 90-100%; your safety is more important than anything else.
-> Store at 80% if you plan to use your cells occasionally, like most of my flashlights
-> Store at 10-20% SOC (around 3-3.2V) for mid-long term storage
-> 0-10% SOC (2.6-3V) if you store long term and periodically check their voltage.

For assembled battery packs:

-> Store at 30% for long term storage while periodically checking pack charge; this is true for any packs that use lithium ion cells, particularly those with any amount of silicon in their anode.
-> Avoid keeping your battery packs fully charged if you don't use them immediately. Immediate usage at 100% is better for long term life, so take advantage of things like adaptive charging/timed charging/Just In Time storage.
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Does this apply also for non silicon oxide cells? The lower the SoC the better for storage?
 
Yeah NASA found out this stuff over a decade ago and it's still generally true for lithium batteries:

- shallower cycles, especially if you're cutting voltage off the top, extend life. The shallower, the better.
- the closer to the middle of the charge the battery is stored at, the better

I've tried to find this research paper by them from the 2010's but can't find it anymore :(
 
yeah, I've seen this study. but what confuses me is, that all manufacturers are shipping their new cells with 3,4-3,6V voltage, instead of 3V or even lower. Self discharge isn't that big.

(sorry for stealing this thread 🫣)
 
freesty said:
yeah, I've seen this study. but what confuses me is, that all manufacturers are shipping their new cells with 3,4-3,6V voltage, instead of 3V or even lower. Self discharge isn't that big.

(sorry for stealing this thread 🫣)
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Do note that many manufacturers employ full voltage cell formation, so discharging to a lower voltages takes more time.

For others that don't, instead performing formation to 3.5V, lowering it down further costs more money and time.

Also, too low storage voltage is annoying for many pack manufacturers since you won't immediately know if your pack works or not.

Finally, too low storage voltage might prove dangerous for finished packages to due to external self-discharge.
 
BlueSwordM said:
Do note that many manufacturers employ full voltage cell formation, so discharging to a lower voltages takes more time.

For others that don't, instead performing formation to 3.5V, lowering it down further costs more money and time.

Also, too low storage voltage is annoying for many pack manufacturers since you won't immediately know if your pack works or not.

Finally, too low storage voltage might prove dangerous for finished packages to due to external self-discharge.
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alright, valid arguments. Got it.
And the difference in degradation isnt significant in moderat temps, not worth the extra afford.
 
Domestic storage battery costs… getting better.
Just as an FYI to you non Aussies, the Australian government have recently (July) introduced a rebate scheme for homebased storage batteries.
This has resulted in a sudden wave of offers from solar and battery retailers, such as these below..
note :— prices are in Aussie dollars, delivered and fully installed by licienced Trades.
That 42 kWh offer works out at Au$ 154 /kWh …or US$ 100 /kWh
without installation the offer is about US$82.0 /kWh
The Aldi offer is for a complete Solar system with 20 kWh battery , installed .
IMG_0539.jpegIMG_0535.png
 
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Hillhater said:
Domestic storage battery costs… getting better.
Just as an FYI to you non Aussies, the Australian government have recently (July) introduced a rebate scheme for homebased storage batteries.
This has resulted in a sudden wave of offers from solar and battery retailers, such as these below..
note :— prices are in Aussie dollars, delivered and fully installed by licienced Trades.
That 42 kWh offer works out at Au$ 154 /kWh …or US$ 100 /kWh
without installation the offer is about US$82.0 /kWh
The Aldi offer is for a complete Solar system with 20 kWh battery , installed .
View attachment 377414View attachment 377415
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This is really competitive for home storage, thanks for sharing
 
I wonder when we'll see teardowns and analysis of CATL's anode-free LFP cells.

That would be one juicy article...
 
600Wh/kg SS batteries in vehicle trials next year?

globalchinaev.com

China's no.1 car exporter Chery unveils solid-state battery with 1,300 km range

Chery introduced a 600 Wh/kg all-solid-state battery at its 2025 Global Innovation Conference, targeting 1,300 km real-world range and pilot deployment by 2026, ahead of rivals BYD and CATL.
globalchinaev.com globalchinaev.com

At the 2025 Chery Global Innovation Conference held on October 18 in Wuhu, Chery Automobile unveiled its first self-developed all-solid-state battery prototype, achieving an energy density of 600 Wh/kg—over twice that of current liquid lithium-ion cells
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Woah woah, trivia dump:

They're using an anode-free sodium cell design?!! How does it only achieve 175Wh/kg then?

That must mean the cathode they chose must have very low specific energy, or that cathode/anode loading is very low to keep IR super low.

Hopefully this means 250-275Wh/kg sodium-ion cells are possible :)
 
BlueSwordM said:
They're using an anode-free sodium cell design?!! How does it only achieve 175Wh/kg then?
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Might have been the EV “battery” density…the whole pack and not just the cell?
175W/kg is pretty good though for a full-production cell IMO. Those >200Wh/kg numbers we see touted by marketing aren’t for fully commercialized cells.
 
BlueSwordM said:
Hopefully this means 250-275Wh/kg sodium-ion cells are possible :)
Click to expand...

Shirley meng repeatedly insists that sodium ion batteries could attain the same whrs/kg as regular lithium batteries.
The only problem with these so far is that the voltage curve is unfortunately shaped..

1761888114183.png

But if we can get good energy density out of them and they don't have a 0.5% chance of turning into a fireball, i think the public would be willing to adopt them, even if that aspect is kinda like incandescents versus compact flourescents ( more efficient, but way worse spectrum of light output )
 
That voltage range seems as if the low end of the capacity is basically unusable since current would need to increase so much in high power use.
 
neptronix said:
Shirley meng repeatedly insists that sodium ion batteries could attain the same whrs/kg as regular lithium batteries.
The only problem with these so far is that the voltage curve is unfortunately shaped..

View attachment 379850

But if we can get good energy density out of them and they don't have a 0.5% chance of turning into a fireball, i think the public would be willing to adopt them, even if that aspect is kinda like incandescents versus compact flourescents ( more efficient, but way worse spectrum of light output )
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Of course sodium-ion cells could eventually get the same specific energy as current lithium-ion cells, but by then, lithium-ion cells will probably have double, or triple the specific energy with LMR cathodes by then.

However, Mooch does make a good point.

As for my point of view, I still stand by my speculation that CATL is prioritizing power density at low temperatures and absolute maximum battery lifetime probably approaching the 30-50 year mark.

You also made me think of a very interesting hypothesis: since anode free designs are the cheapest designs if done optimally, this has to be related to cost optimizations and specific energy increases.

This also has other implications: they can make any cell design anode-free at this point.

Finally, since metal anodes tend to have higher potentials, this should increase the energy available at higher voltages, increasing the nominal voltage and making battery management easier.
 
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