[userbinator]

...and 5x shorter cycle life?

Observe the noticeable lack of any mention of how many cycles a cell will last at this charge rate. It is well known that ordinary li-ion cell can be charged extremely fast too, as long as you don't charge so fast it heats up rapidly and goes into explosive thermal runaway, but it shortens the lifetime considerably.

[Defenestresque]

You probably missed it, but the nature.com article that some commenters have referenced [1] has more details, including information on the charge rate.

> A full-cell incorporating graphene balls increases the volumetric energy density by 27.6% compared to a control cell without graphene balls, showing the possibility of achieving 800 Wh L−1 in a commercial cell setting, along with a high cyclability of 78.6% capacity retention after 500 cycles at 5C and 60 °C.

In your other comment you write:

>the standard is 80% capacity after 500 cycles at the normally specified (1C) charge rate

So I'd say that's pretty good.

[1] https://www.nature.com/articles/s41467-017-01823-7

[dtx1]

> A full-cell incorporating graphene balls increases the volumetric energy density by 27.6% compared to a control cell without graphene balls, showing the possibility of achieving 800 Wh L−1 in a commercial cell setting, along with a high cyclability of 78.6% capacity retention after 500 cycles at 5C and 60 °C.

Does that mean 5C Charge rate and > 5C Discharge? Because in the EV Market 5C discharge would be borderline enough (I think Teslas 18650 discharge at a peak of 20A per ~3,5Ah Cell so 5C Discharge would be cutting it very close.)

If it's 5C Charge and getting to 500 cycles with higher discharge then...woah.

[hwillis]

Read the paper, it has the same cycle life at 5x the C rate (compared to plain NMO chemistry).

[baddox]

I wasn’t aware that faster charging shortens lifetimes. Does that mean that (using completely made-up numbers) that a battery will reduce to 80% its initial capacity after 10,000 slow charges, but after 10,000 fast charges its capacity would reduce to, say, 50%?

[userbinator]

You have the right idea, but your completely made-up numbers are not even close --- the standard is 80% capacity after 500 cycles at the normally specified (1C) charge rate. If my vague recollection of the last time I read about this is correct, at 2C (twice as fast), after 500 cycles the capacity remaining may be more like 20%. It's definitely nonlinear.

Heres an "entry" article: https://kabru.eecs.umich.edu/wordpress/wp-content/uploads/St...

and you can follow the references from there (into SciHub etc. if need be.)

[hwillis]

Discharge depth is far, far more important.

[baddox]

Ouch, that is much worse than my intuition!