Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Stanford researchers make rechargeable batteries that store 6x more charge

news.stanford.edu

Post reply on HN
Print view View original

31–40 of 67 posts

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#31

Post by snazz »

twoslide wrote: post #30
__s wrote: post #28

Earlier quoted context omitted.

You didn't x off any of the reasons. This list of common pitfalls is nice, but without marking which pitfalls apply you've added nothing to the conversation The earliest instance of it _did_ offer this, https://news.ycombinator.com/item?id=26353853 But it seems afterwards people have done the easy part, pasting the list, & not the hard part, reviewing the article closely enough to share with others what hard problems…

The press release is naturally all positive spin, but hints at: [X] it suffers from too few recharge cycles. They mention 200 cycles, whereas 1000+ is common for li-ion.

In theory that would be fine if devices continued using the same amount of energy. Instead of charging my phone every night, if I charged it every six nights, it doesn’t need to last for as many charge cycles either.

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#32

Post by rsfern »

squarefoot wrote: post #22

"sodium chloride (Na/Cl2)" I'm not chemist, but if I recall correctly, sodium chloride is NaCl, not NaCl2, ie common kitchen salt.

The primary reaction at the cathode is reported as Na + 0.5 Cl2 NaCl

(Reported in the paper, which is unfortunately not open access. https://www.nature.com/articles/s41586-021-03757-z)

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#33

Post by twoslide »

Really interesting to compare with the publication itself:

https://www.nature.com/articles/s41586-021-03757-z

They don't mention six times more charge anywhere. Rather, the novelty is that it they make a discharge reaction re-chargeable for the first time. The final paragraph hints at a rapid drop-off after the first discharge:

> The battery delivered about 3,309 mAh first discharge capacity and was cyclable at 500–1,200 mAh.

One can see a benefit in that a previous single-use battery could be cycled (e.g. a hearing aid). The press release claim is such a stretch as to be essentially a lie:

> a high-performance rechargeable battery that could enable cellphones to be charged only once a week instead of daily and electric vehicles that can travel six times farther

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#34

Post by thatguy0900 »

twoslide wrote: post #33

Really interesting to compare with the publication itself: https://www.nature.com/articles/s41586-021-03757-z They don't mention six times more charge anywhere. Rather, the novelty is that it they make a discharge reaction re-chargeable for the first time. The final paragraph hints at a rapid drop-off after the first discharge: > The battery delivered about 3,309 mAh first discharge capacity and was cyclable at 500–1…

Must be incredibly frustrating to be a researcher and see the media absolutely butcher things you worked on

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#36

Post by rsfern »

twoslide wrote: post #33

Really interesting to compare with the publication itself: https://www.nature.com/articles/s41586-021-03757-z They don't mention six times more charge anywhere. Rather, the novelty is that it they make a discharge reaction re-chargeable for the first time. The final paragraph hints at a rapid drop-off after the first discharge: > The battery delivered about 3,309 mAh first discharge capacity and was cyclable at 500–1…

I agree about the press release. Though they do run it out to ~100 cycles without too much apparent further degradation, so it’s probably not dead on arrival as a contender against Li-ion?

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#37

Post by wolverine876 »

poisonborz wrote: post #8

For how important it is to modern society, the somewhat stagnating state of battery technology in comparison is baffling. Obviously there is a lot of $ thrown on this problem (securing the constant flow of such hopeful articles in the since the 2000s) but per feeling most of the gains since the Nokia days comes from improving HW/SW efficiency.

> For how important it is to modern society ...

Many problems important to modern society are unsolved: Cancer, malaria, poverty, politics, Coronavirus, fusion energy, universal language translators, education, etc.

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#38

Post by UncleMeat »

snazz wrote: post #31
twoslide wrote: post #30

Earlier quoted context omitted.

The press release is naturally all positive spin, but hints at: [X] it suffers from too few recharge cycles. They mention 200 cycles, whereas 1000+ is common for li-ion.

In theory that would be fine if devices continued using the same amount of energy. Instead of charging my phone every night, if I charged it every six nights, it doesn’t need to last for as many charge cycles either.

A lot of compute on devices is currently battery limited. Manufacturers try hard to keep a charge at one day but don't really care beyond that. If we instantly replaced batteries with ones that lasted 5x longer and lasted 1/5th the cycles, I'd expect phones to instead use 5x the power in a single day since all of the metrics that currently resist waste right now would not longer be launch blockers for power-hungry features.

Re: Stanford researchers make rechargeable batteries that store 6x more charge

#39

Post by twoslide »

snazz wrote: post #31
twoslide wrote: post #30

Earlier quoted context omitted.

The press release is naturally all positive spin, but hints at: [X] it suffers from too few recharge cycles. They mention 200 cycles, whereas 1000+ is common for li-ion.

In theory that would be fine if devices continued using the same amount of energy. Instead of charging my phone every night, if I charged it every six nights, it doesn’t need to last for as many charge cycles either.

They also mention a rapid drop-off in capacity after the first cycle in the article itself (3600 mAh to 1200 mAh). The main point the authors are making is that the discharge process is rechargeable rather than a single discharge. The press release uses this finding to make rather ambitious claims.
Post reply on HN