9 ms·

'Bath sponge' breakthrough could boost cleaner cars

95 points by fpoling 7y ago

gok 7y ago
It's a novel way to store hydrogen instead of a traditional high pressure tank. This is a teeny tiny problem for a hydrogen cars. It doesn't really address the problem that fuel cells are ridiculously expensive, or that there's no filling network, or that there's no good way to fill them at home, or that fuel cells are themselves only 50% efficient typically.
- SuoDuanDao 7y ago
  Fair enough - but as to the filling network at least, that seems a lot more feasible given a decent way to store it.
  - jimmySixDOF 7y ago
    RIP Better Place (2007-2013). They were ahead of their time and if hydrogen refueling stations take off it will be following in their footsteps. [1] https://en.m.wikipedia.org/wiki/Better_Place_(company) https://en.m.wikipedia.org/wiki/Better_Place_(company)
- jkqwzsoo 7y ago
  MOF-based hydrogen storage has been around since at least 2003 (Omar Yaghi on MOF-5). Its hardly a novel concept. I haven’t read this paper, I just skimmed for figure out what the “aluminum sponge” was until I saw it was Farha and MOFs. As far as I can tell, this is in Science because it surpasses key benchmarks set by the DOE, not because it’s a new idea. This is a particularly high surface area MOF (>7300 m^2/g). I recently picked up a MOF project (not related to hydrogen storage) with derivatives of a popular MOF and it’s closer to 1000 m^2/g. Zeolites (a much more established class of porous material) are about a quarter of that (<200-300). An actual metal sponge (what I thought the article was talking about) is <~20 m^2/g.
- gpapilion 7y ago
  I’ve always thought the distribution issue it’s the largest problem for alternative fuel vehicles. Driving to Los Angeles from San Francisco is extremely difficult for either a fuel cell or ev vehicle (that’s not a Tesla, and it’s also true for cng vehicles). This is admittedly not a daily use case, but highlights the issues with refueling. It’s hard to see either technology being our primary transportation mode without solving some of this. EVs have an advantage for fuel availability, but issues around fueling time.
  - logical42 7y ago
    There are enough CNG stations to drive from SF to LA as long as you fill up appropriately.
    - toast0 7y ago
      I had researched buying a CNG car in the LA area and bringing it back to San Jose. Reliable miles per tank data was tough to come by, but it seemed like if you couldn't use PG&E stations to fill (because it requires pre-registration, and a certified inspection), you wouldn't be able to take the most direct route. That was for a crown victoria/lincoln town car though. I don't know if the civic's get more miles per tank.
  - halfdan 7y ago
    I think there's a common misconception in your argument. Even without a full distribution network it might be a viable solution. Most of us use our cars for our daily commute, grocery shopping and other things within a fairly small radius. The few times we would need to drive the SF->LA distance you can easily take a rental. The mistake is to assume that we would use "alternative fuel" vehicles the same way we would our petrol cars.
    - greglindahl 7y ago
      I don't think there's an assumption there. The alternative fuel cars that sell well are the long-range ones. Sure, people mostly drive them locally, but it appears to be the case that there's comfort in knowing that they can also go long distance.
- mrfusion 7y ago
  Good points. I’ve always been curious. Why not just plug in A hydrogen car and run the fuel cell in reverse to get a tank of hydrogen?
  - pmorici 7y ago
    The only reason that Hydrogen powered cars are even still discussed over battery electric is that 95% of industrial hydrogen is produced from fossil fuels. In other words the people pushing it are probably protecting their oil and gas interests. They aren't going to put money into research to cut themselves out of the loop. [0] https://en.wikipedia.org/wiki/Hydrogen_production https://en.wikipedia.org/wiki/Hydrogen_production
    - Hypx 7y ago
      But nobody is suggesting that industrial hydrogen will be natural gas based forever. Furthermore, we must have green hydrogen for steel and ammonia production. So this is a “must solve” problem no matter what. This is basically the same kind of argument that BEVs are “secretly powered by coal.” These are backwards looking statements that are going to be wrong in the near future.
    - clouddrover 7y ago
      > In other words the people pushing it are probably protecting their oil and gas interests. Shell builds EV charging stations: https://www.youtube.com/watch?v=nst2RGtgzfk https://www.youtube.com/watch?v=nst2RGtgzfk BP builds EV charging stations: https://www.youtube.com/watch?v=zaSRn6hYOwc https://www.youtube.com/watch?v=zaSRn6hYOwc Petro-Canada builds EV charging stations: https://www.petro-canada.ca/en/personal/fuel/canadas-electric-highway https://www.petro-canada.ca/en/personal/fuel/canadas-electri... They're in the energy business. They don't really care what form it takes.
      - blibble 7y ago
        in a world where everyone has a charger at home and at work there's little to no need for Shell and BP hence their push for hydrogen, where everything remains essentially the same (and they keep their vertically integrated business)
- gryzzly 7y ago
  Or that pollution from tires is a serious problem and SUV-level weight moving at high speeds is not something we need more of.
  - kevin_thibedeau 7y ago
    Most "SUVs" are just station wagons with an extra inch of ground clearance. They aren't that heavy. A Prius, on the other hand is close to the weight of a light truck.
    - PhantomGremlin 7y ago
      A Prius, on the other hand is close to the weight of a light truck. I was real confused by this. Wiki says Prius is in the range of 3,000 lbs. Much lighter than a truck of any sort. Perhaps you meant to say Tesla Model X instead of Prius? That the closest comparison to an SUV. It weighs in at well over 5,000 lbs, which closer to the range of a light truck. https://en.wikipedia.org/wiki/Toyota_Prius_(XW50) https://en.wikipedia.org/wiki/Toyota_Prius_(XW50) https://en.wikipedia.org/wiki/Tesla_Model_X https://en.wikipedia.org/wiki/Tesla_Model_X
      - pokeymcsnatch 7y ago
        He may have meant "small truck" instead of light truck? "light truck" has a specific definition and it's probably not what most people would think when using or hearing the term. A Prius is about the same weight as a lot of small trucks, or at least what small trucks used to be before the weird side-effects of fuel-efficiency regulations: 2005 Tacoma: 3,140 to 4,4100 lbs 2005 Ranger: 3,028 to 3,606 lbs 2003 S-10: 3,016 to 4,039 lbs
    - mrpopo 7y ago
      The best-selling Hyundai all-categories SUV in the US is the Hyundai Santa Fe and weighs in average 1.8t. The fact that there are lighter SUVs appearing on the market is encouraging, but your affirmation is most likely not true.
  - 7y ago
- Hypx 7y ago
  Basically everything you said is wrong. The costs of fuel cells are dropping so fast, that that is probably the main driver of interest in fuel cell technology recently. The filling stations are being installed by dozens around the world right now. Fuel cells have reach 60% efficiency in real world testing. It’s been something of a blind spot among tech workers that they are completely oblivious to the gains made in fuel cells. For all the hype about us being forward thinking, a lot of us are seriously stuck in the past.
  - casion 7y ago
    OP mentioned things that exist now, your response seems to be that things are improving. Those ideas aren't at odds.
  - reissbaker 7y ago
    It's not much of a blind spot. Fuel cells are worse for consumer cars than batteries, both in environmental terms and in terms of convenience. A BEV can recharge at home using existing standard outlets (a 240v 30A or 50A dryer outlet for good performance, or even a 120v regular outlet will do if you're willing to wait a while); good luck refilling a fuel cell. BEVs are nearly 80% efficient already [1], are comparatively widely deployed, and the infrastructure for them exists in everyone's home. For long distance travel, there are far more fast chargers than hydrogen stations, and far more investment in building more of them. Also, most independent real-world tests I've seen of hydrogen cells reported much lower efficiency in practice than claimed — often between 30-40%. The only tank-to-wheel 60% claim I could find was a statement by Honda of their own car; FWIW, the EPA rating of the latest, most-efficient version of that car (the Honda Clarity Fuel Cell) is actually 68 MPGe [2], which is much lower than most BEVs. In fact, the battery-based version of the same exact car, the Honda Clarity EV, has an EPA rating of 114 MPGe [3], which is nearly 70% more efficient. Hydrogen fuel cells for consumer cars just don't make sense. 1: https://www.fueleconomy.gov/feg/evtech.shtml https://www.fueleconomy.gov/feg/evtech.shtml 2: https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=40044 https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=40044 3: https://www.fueleconomy.gov/feg/noframes/41185.shtml https://www.fueleconomy.gov/feg/noframes/41185.shtml
    - 7y ago
rcMgD2BwE72F 7y ago
>Now, researchers believe they have developed an alternative method that would allow the storage of high volumes of hydrogen under much lower pressure. They'll still be 100 reasons to favor battery EVs to renewable hydrogen fuel cells. Better storage does not increase its inferior well-to-wheel efficiency.
- Hypx 7y ago
  That’s really the only reason to favor BEVs over hydrogen. Everything else, from weight, cost (eventually), range, raw material requirements, are better with fuel cells.
maga 7y ago
I'd like to know how it compares to existing solutions, the only thing I see in abstract is meeting/exceeding some US gov target. Can someone knowledgeable weigh in on this? How big of progress is this?
bcatanzaro 7y ago
Hydrogen storage may be useful in the future. But probably not for cars. Battery EVs are better environmentally (much lower carbon footprint and higher efficiency), have longer range and more power. It’s too bad the story had to be written about car applications rather than the MOF itself.
- Hypx 7y ago
  I beg to differ. You still need an absolutely massive amount of raw material for batteries. This is it’s own environmental problem unrelated to climate change. Fuel cell cars can easily have 500km+ ranges and upwards of 900hp if you really wanted that much power. Not sure how you can argue this point at all.
credit_guy 7y ago
Summary for those who didn't click on the link to the actual article [1]: - a car may need 5 kg of hydrogen for a range of 500km (bbc's claim, I'll take it at face value) - the new "sponge" material can offer "deliverable hydrogen capacities (14.0 weight %, 46.2 g liter−1) under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar)." - so for 5kg of H2 you need about 100 l of this material, at a weight of about 35 kg. Not too shabby. - however, note the conditions: you store the H2 at 77k and 100bar. So you need liquid nitrogen and quite high pressure to hold this. That might add substantial weight to the 35kg of sponge By the way, about one year ago, there was quite some big noise on HN about a different breakthrough from Australia, where some researchers showed economic ways to store H2 in ammonia. Not sure if that got anywhere. [1] https://science.sciencemag.org/content/368/6488/297 https://science.sciencemag.org/content/368/6488/297
- greglindahl 7y ago
  The main utility for ammonia is to transport energy long distances at industrial scale, not for individual vehicles. So, for example, you'd build a huge solar farm where it's very sunny, or a huge wind farm where it's windy. And instead of running power lines, you'd ship ammonia.
  - jessaustin 7y ago
    Power lines are cheaper and more efficient than pipelines, and they always will be. Ammonia will be a storage medium.
    - greglindahl 7y ago
      So, for example, a power line from Algeria to Europe is cheaper than a ship-based ammonia scheme? Or northern Australia to China or Japan? Power lines are a winner for short distances. Pipelines some longer distances. And ships for the longest distances.
      - brownbat 7y ago
mrfusion 7y ago
Could this have other uses? Spacecraft?
- joshuaheard 7y ago
  I wonder if this same principle could be used to store air for scuba tanks. It would be an improvement over existing compressed air tanks if the tank could be made smaller and lighter.
lowdose 7y ago
Sounds like an artificial zeolite. https://en.m.wikipedia.org/wiki/Zeolite https://en.m.wikipedia.org/wiki/Zeolite
- jkqwzsoo 7y ago
  It's a MOF (metal-organic framework). Basically a metal ion or metal cluster linked (nodes) together with organic molecules (linkers or struts). Some of them are even stable in aqueous solutions (like UiO-66). Typically, the linker-metal bond is via a carboxylic acid, and the metal node is something like... Zr, Ce, Hf, Ti, Fe, Cu, Co, Mn, Al, etc. etc. They've been the gold standard for gas sorption and hydrogen-car promises for at least 17 years. The actual term MOF was apparently first used in 95[0]. While there are a lot of things that can affect the synthesis (metal concentration, metal precursor, metal:linker ratio, solvent choice, presence or absence of water, modulators, synthesis temperature), the synthesis of MOFs is usually about tuning what goes into the pot. Then its shake-n-bake and MOF comes out a day later (solvothermal method). So, it's an easy synthesis if you know what to load into your reaction vessel. While continuous synthesis is a harder, I think it's a lot more immediately scalable than porous aromatic frameworks (PAFs). This work is combining some of the advantages of MOF (high specific surface area, regular structure, easy synthesis) with some of the advantages of PAFs (even higher specific surface area). You can see the linker they use on PDF page 5 of the supplementary online material[1]. The hexadentate structure is large and is reminiscent of PAFs like PAF-1[2], which are known for having very high specific surface area. This is because the aryl group has a high specific surface area. By making the linker very large and bulky, they're reducing the contribution of the metal nodes to the specific surface area by having a greater volume fraction of (lightweight) aromatic linker. However, while PAFs usually (always? I'm not a PAF person) have an SP3 carbon center (and thus a tetrahedral symmetry), this linker is kind of shaped like a paddle wheel with three paddles (or a trigonal prism, if you access the Science article and see Fig. 1). Thus, while PAFs are typically in a diamond-like net (dia [3]), this MOF is in a acs net[4]. [0] https://www.nature.com/milestones/milecrystal/full/milecrystal22.html https://www.nature.com/milestones/milecrystal/full/milecryst... [1] https://science.sciencemag.org/content/sci/suppl/2020/04/15/368.6488.297.DC1/aaz8881_Chen_SM.pdf https://science.sciencemag.org/content/sci/suppl/2020/04/15/... [2] dx.doi.org/10.1039/C4MH00163J, http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf [3] http://rcsr.anu.edu.au/nets/dia http://rcsr.anu.edu.au/nets/dia [4] http://rcsr.anu.edu.au/nets/acs http://rcsr.anu.edu.au/nets/acs Fun fact: Most MOFs are named after the research institution that found them first. This one is named NU-1500 for Northwestern University, where Farha is. The UiO-series are named after Universitet i Oslo, the HKUST series is named for Hong Kong University of Science and Technology, the MIL series is named for Material Insitute Lavoisier.
wishinghand 7y ago
This is good research for low-pressure hydrogen storage, but I think pursuing hydrogen powered cars is folly. It still has to be mined or generated, refined, and transported to filling stations, whereas with electric cars the transport and filling network is already in place. It's still a middleman to lose efficiency that electric cars don't have.
- erik_seaberg 7y ago
  Hydrogen could be a win if we can get it into the tank in a couple minutes. Very few apartments or workplaces have EV chargers so far, and it's impractically slow to do anywhere you weren't planning to park for a long time. A Tesla Supercharger station would have to be 10x as big as a gas station to accommodate the general public stopping for a half hour each for a partial charge, assuming they would put up with the wait.
  - greglindahl 7y ago
    You could have made the same comment 6 years ago, and behold, lots more people drive EVs today than 6 years ago. There's been a lot of progress in cajoling and requiring apartment complexes and workplaces to install chargers, and Tesla has a lot more superchargers (mostly in mall parking lots) than they used to have. So it sure doesn't seem like there's any insurmountable problem involved that would cause us to stop promoting EVs. Meanwhile, hydrogen fuel cells haven't fallen in price like Toyota predicted, and so their hydrogen car is both expensive and low performance. Not a winning combination, even if it fuels up in 5 minutes.
    - erik_seaberg 7y ago
      It's not impossible, but the network is still far from "already in place". Wikipedia says US plug-in EV ownership is only 3.4%, and those drivers had better all own houses with attached garages.
      - greglindahl 7y ago
jwilk 7y ago
For a moment I thought it's going to be about car washing.

95 points by fpoling 7y ago

gok 7y ago

It's a novel way to store hydrogen instead of a traditional high pressure tank. This is a teeny tiny problem for a hydrogen cars. It doesn't really address the problem that fuel cells are ridiculously expensive, or that there's no filling network, or that there's no good way to fill them at home, or that fuel cells are themselves only 50% efficient typically.

SuoDuanDao 7y ago
Fair enough - but as to the filling network at least, that seems a lot more feasible given a decent way to store it.
- jimmySixDOF 7y ago
  RIP Better Place (2007-2013). They were ahead of their time and if hydrogen refueling stations take off it will be following in their footsteps. [1] https://en.m.wikipedia.org/wiki/Better_Place_(company) https://en.m.wikipedia.org/wiki/Better_Place_(company)
jkqwzsoo 7y ago
MOF-based hydrogen storage has been around since at least 2003 (Omar Yaghi on MOF-5). Its hardly a novel concept. I haven’t read this paper, I just skimmed for figure out what the “aluminum sponge” was until I saw it was Farha and MOFs. As far as I can tell, this is in Science because it surpasses key benchmarks set by the DOE, not because it’s a new idea. This is a particularly high surface area MOF (>7300 m^2/g). I recently picked up a MOF project (not related to hydrogen storage) with derivatives of a popular MOF and it’s closer to 1000 m^2/g. Zeolites (a much more established class of porous material) are about a quarter of that (<200-300). An actual metal sponge (what I thought the article was talking about) is <~20 m^2/g.
gpapilion 7y ago
I’ve always thought the distribution issue it’s the largest problem for alternative fuel vehicles. Driving to Los Angeles from San Francisco is extremely difficult for either a fuel cell or ev vehicle (that’s not a Tesla, and it’s also true for cng vehicles). This is admittedly not a daily use case, but highlights the issues with refueling. It’s hard to see either technology being our primary transportation mode without solving some of this. EVs have an advantage for fuel availability, but issues around fueling time.
- logical42 7y ago
  There are enough CNG stations to drive from SF to LA as long as you fill up appropriately.
  - toast0 7y ago
    I had researched buying a CNG car in the LA area and bringing it back to San Jose. Reliable miles per tank data was tough to come by, but it seemed like if you couldn't use PG&E stations to fill (because it requires pre-registration, and a certified inspection), you wouldn't be able to take the most direct route. That was for a crown victoria/lincoln town car though. I don't know if the civic's get more miles per tank.
- halfdan 7y ago
  I think there's a common misconception in your argument. Even without a full distribution network it might be a viable solution. Most of us use our cars for our daily commute, grocery shopping and other things within a fairly small radius. The few times we would need to drive the SF->LA distance you can easily take a rental. The mistake is to assume that we would use "alternative fuel" vehicles the same way we would our petrol cars.
  - greglindahl 7y ago
    I don't think there's an assumption there. The alternative fuel cars that sell well are the long-range ones. Sure, people mostly drive them locally, but it appears to be the case that there's comfort in knowing that they can also go long distance.
mrfusion 7y ago
Good points. I’ve always been curious. Why not just plug in A hydrogen car and run the fuel cell in reverse to get a tank of hydrogen?
- pmorici 7y ago
  The only reason that Hydrogen powered cars are even still discussed over battery electric is that 95% of industrial hydrogen is produced from fossil fuels. In other words the people pushing it are probably protecting their oil and gas interests. They aren't going to put money into research to cut themselves out of the loop. [0] https://en.wikipedia.org/wiki/Hydrogen_production https://en.wikipedia.org/wiki/Hydrogen_production
  - Hypx 7y ago
    But nobody is suggesting that industrial hydrogen will be natural gas based forever. Furthermore, we must have green hydrogen for steel and ammonia production. So this is a “must solve” problem no matter what. This is basically the same kind of argument that BEVs are “secretly powered by coal.” These are backwards looking statements that are going to be wrong in the near future.
  - clouddrover 7y ago
    > In other words the people pushing it are probably protecting their oil and gas interests. Shell builds EV charging stations: https://www.youtube.com/watch?v=nst2RGtgzfk https://www.youtube.com/watch?v=nst2RGtgzfk BP builds EV charging stations: https://www.youtube.com/watch?v=zaSRn6hYOwc https://www.youtube.com/watch?v=zaSRn6hYOwc Petro-Canada builds EV charging stations: https://www.petro-canada.ca/en/personal/fuel/canadas-electric-highway https://www.petro-canada.ca/en/personal/fuel/canadas-electri... They're in the energy business. They don't really care what form it takes.
    - blibble 7y ago
      in a world where everyone has a charger at home and at work there's little to no need for Shell and BP hence their push for hydrogen, where everything remains essentially the same (and they keep their vertically integrated business)
gryzzly 7y ago
Or that pollution from tires is a serious problem and SUV-level weight moving at high speeds is not something we need more of.
- kevin_thibedeau 7y ago
  Most "SUVs" are just station wagons with an extra inch of ground clearance. They aren't that heavy. A Prius, on the other hand is close to the weight of a light truck.
  - PhantomGremlin 7y ago
    A Prius, on the other hand is close to the weight of a light truck. I was real confused by this. Wiki says Prius is in the range of 3,000 lbs. Much lighter than a truck of any sort. Perhaps you meant to say Tesla Model X instead of Prius? That the closest comparison to an SUV. It weighs in at well over 5,000 lbs, which closer to the range of a light truck. https://en.wikipedia.org/wiki/Toyota_Prius_(XW50) https://en.wikipedia.org/wiki/Toyota_Prius_(XW50) https://en.wikipedia.org/wiki/Tesla_Model_X https://en.wikipedia.org/wiki/Tesla_Model_X
    - pokeymcsnatch 7y ago
      He may have meant "small truck" instead of light truck? "light truck" has a specific definition and it's probably not what most people would think when using or hearing the term. A Prius is about the same weight as a lot of small trucks, or at least what small trucks used to be before the weird side-effects of fuel-efficiency regulations: 2005 Tacoma: 3,140 to 4,4100 lbs 2005 Ranger: 3,028 to 3,606 lbs 2003 S-10: 3,016 to 4,039 lbs
  - mrpopo 7y ago
    The best-selling Hyundai all-categories SUV in the US is the Hyundai Santa Fe and weighs in average 1.8t. The fact that there are lighter SUVs appearing on the market is encouraging, but your affirmation is most likely not true.
- 7y ago
Hypx 7y ago
Basically everything you said is wrong. The costs of fuel cells are dropping so fast, that that is probably the main driver of interest in fuel cell technology recently. The filling stations are being installed by dozens around the world right now. Fuel cells have reach 60% efficiency in real world testing. It’s been something of a blind spot among tech workers that they are completely oblivious to the gains made in fuel cells. For all the hype about us being forward thinking, a lot of us are seriously stuck in the past.
- casion 7y ago
  OP mentioned things that exist now, your response seems to be that things are improving. Those ideas aren't at odds.
- reissbaker 7y ago
  It's not much of a blind spot. Fuel cells are worse for consumer cars than batteries, both in environmental terms and in terms of convenience. A BEV can recharge at home using existing standard outlets (a 240v 30A or 50A dryer outlet for good performance, or even a 120v regular outlet will do if you're willing to wait a while); good luck refilling a fuel cell. BEVs are nearly 80% efficient already [1], are comparatively widely deployed, and the infrastructure for them exists in everyone's home. For long distance travel, there are far more fast chargers than hydrogen stations, and far more investment in building more of them. Also, most independent real-world tests I've seen of hydrogen cells reported much lower efficiency in practice than claimed — often between 30-40%. The only tank-to-wheel 60% claim I could find was a statement by Honda of their own car; FWIW, the EPA rating of the latest, most-efficient version of that car (the Honda Clarity Fuel Cell) is actually 68 MPGe [2], which is much lower than most BEVs. In fact, the battery-based version of the same exact car, the Honda Clarity EV, has an EPA rating of 114 MPGe [3], which is nearly 70% more efficient. Hydrogen fuel cells for consumer cars just don't make sense. 1: https://www.fueleconomy.gov/feg/evtech.shtml https://www.fueleconomy.gov/feg/evtech.shtml 2: https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=40044 https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=40044 3: https://www.fueleconomy.gov/feg/noframes/41185.shtml https://www.fueleconomy.gov/feg/noframes/41185.shtml
  - 7y ago

rcMgD2BwE72F 7y ago

>Now, researchers believe they have developed an alternative method that would allow the storage of high volumes of hydrogen under much lower pressure. They'll still be 100 reasons to favor battery EVs to renewable hydrogen fuel cells. Better storage does not increase its inferior well-to-wheel efficiency.

Hypx 7y ago
That’s really the only reason to favor BEVs over hydrogen. Everything else, from weight, cost (eventually), range, raw material requirements, are better with fuel cells.

maga 7y ago

I'd like to know how it compares to existing solutions, the only thing I see in abstract is meeting/exceeding some US gov target. Can someone knowledgeable weigh in on this? How big of progress is this?

bcatanzaro 7y ago

Hydrogen storage may be useful in the future. But probably not for cars. Battery EVs are better environmentally (much lower carbon footprint and higher efficiency), have longer range and more power. It’s too bad the story had to be written about car applications rather than the MOF itself.

Hypx 7y ago
I beg to differ. You still need an absolutely massive amount of raw material for batteries. This is it’s own environmental problem unrelated to climate change. Fuel cell cars can easily have 500km+ ranges and upwards of 900hp if you really wanted that much power. Not sure how you can argue this point at all.

credit_guy 7y ago

Summary for those who didn't click on the link to the actual article [1]: - a car may need 5 kg of hydrogen for a range of 500km (bbc's claim, I'll take it at face value) - the new "sponge" material can offer "deliverable hydrogen capacities (14.0 weight %, 46.2 g liter−1) under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar)." - so for 5kg of H2 you need about 100 l of this material, at a weight of about 35 kg. Not too shabby. - however, note the conditions: you store the H2 at 77k and 100bar. So you need liquid nitrogen and quite high pressure to hold this. That might add substantial weight to the 35kg of sponge By the way, about one year ago, there was quite some big noise on HN about a different breakthrough from Australia, where some researchers showed economic ways to store H2 in ammonia. Not sure if that got anywhere. [1] https://science.sciencemag.org/content/368/6488/297 https://science.sciencemag.org/content/368/6488/297

greglindahl 7y ago
The main utility for ammonia is to transport energy long distances at industrial scale, not for individual vehicles. So, for example, you'd build a huge solar farm where it's very sunny, or a huge wind farm where it's windy. And instead of running power lines, you'd ship ammonia.
- jessaustin 7y ago
  Power lines are cheaper and more efficient than pipelines, and they always will be. Ammonia will be a storage medium.
  - greglindahl 7y ago
    So, for example, a power line from Algeria to Europe is cheaper than a ship-based ammonia scheme? Or northern Australia to China or Japan? Power lines are a winner for short distances. Pipelines some longer distances. And ships for the longest distances.
    - brownbat 7y ago

mrfusion 7y ago

Could this have other uses? Spacecraft?

joshuaheard 7y ago
I wonder if this same principle could be used to store air for scuba tanks. It would be an improvement over existing compressed air tanks if the tank could be made smaller and lighter.

lowdose 7y ago

Sounds like an artificial zeolite. https://en.m.wikipedia.org/wiki/Zeolite https://en.m.wikipedia.org/wiki/Zeolite

jkqwzsoo 7y ago
It's a MOF (metal-organic framework). Basically a metal ion or metal cluster linked (nodes) together with organic molecules (linkers or struts). Some of them are even stable in aqueous solutions (like UiO-66). Typically, the linker-metal bond is via a carboxylic acid, and the metal node is something like... Zr, Ce, Hf, Ti, Fe, Cu, Co, Mn, Al, etc. etc. They've been the gold standard for gas sorption and hydrogen-car promises for at least 17 years. The actual term MOF was apparently first used in 95[0]. While there are a lot of things that can affect the synthesis (metal concentration, metal precursor, metal:linker ratio, solvent choice, presence or absence of water, modulators, synthesis temperature), the synthesis of MOFs is usually about tuning what goes into the pot. Then its shake-n-bake and MOF comes out a day later (solvothermal method). So, it's an easy synthesis if you know what to load into your reaction vessel. While continuous synthesis is a harder, I think it's a lot more immediately scalable than porous aromatic frameworks (PAFs). This work is combining some of the advantages of MOF (high specific surface area, regular structure, easy synthesis) with some of the advantages of PAFs (even higher specific surface area). You can see the linker they use on PDF page 5 of the supplementary online material[1]. The hexadentate structure is large and is reminiscent of PAFs like PAF-1[2], which are known for having very high specific surface area. This is because the aryl group has a high specific surface area. By making the linker very large and bulky, they're reducing the contribution of the metal nodes to the specific surface area by having a greater volume fraction of (lightweight) aromatic linker. However, while PAFs usually (always? I'm not a PAF person) have an SP3 carbon center (and thus a tetrahedral symmetry), this linker is kind of shaped like a paddle wheel with three paddles (or a trigonal prism, if you access the Science article and see Fig. 1). Thus, while PAFs are typically in a diamond-like net (dia [3]), this MOF is in a acs net[4]. [0] https://www.nature.com/milestones/milecrystal/full/milecrystal22.html https://www.nature.com/milestones/milecrystal/full/milecryst... [1] https://science.sciencemag.org/content/sci/suppl/2020/04/15/368.6488.297.DC1/aaz8881_Chen_SM.pdf https://science.sciencemag.org/content/sci/suppl/2020/04/15/... [2] dx.doi.org/10.1039/C4MH00163J, http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf http://www.rsc.org/suppdata/mh/c4/c4mh00163j/c4mh00163j1.pdf [3] http://rcsr.anu.edu.au/nets/dia http://rcsr.anu.edu.au/nets/dia [4] http://rcsr.anu.edu.au/nets/acs http://rcsr.anu.edu.au/nets/acs Fun fact: Most MOFs are named after the research institution that found them first. This one is named NU-1500 for Northwestern University, where Farha is. The UiO-series are named after Universitet i Oslo, the HKUST series is named for Hong Kong University of Science and Technology, the MIL series is named for Material Insitute Lavoisier.

wishinghand 7y ago

This is good research for low-pressure hydrogen storage, but I think pursuing hydrogen powered cars is folly. It still has to be mined or generated, refined, and transported to filling stations, whereas with electric cars the transport and filling network is already in place. It's still a middleman to lose efficiency that electric cars don't have.

erik_seaberg 7y ago
Hydrogen could be a win if we can get it into the tank in a couple minutes. Very few apartments or workplaces have EV chargers so far, and it's impractically slow to do anywhere you weren't planning to park for a long time. A Tesla Supercharger station would have to be 10x as big as a gas station to accommodate the general public stopping for a half hour each for a partial charge, assuming they would put up with the wait.
- greglindahl 7y ago
  You could have made the same comment 6 years ago, and behold, lots more people drive EVs today than 6 years ago. There's been a lot of progress in cajoling and requiring apartment complexes and workplaces to install chargers, and Tesla has a lot more superchargers (mostly in mall parking lots) than they used to have. So it sure doesn't seem like there's any insurmountable problem involved that would cause us to stop promoting EVs. Meanwhile, hydrogen fuel cells haven't fallen in price like Toyota predicted, and so their hydrogen car is both expensive and low performance. Not a winning combination, even if it fuels up in 5 minutes.
  - erik_seaberg 7y ago
    It's not impossible, but the network is still far from "already in place". Wikipedia says US plug-in EV ownership is only 3.4%, and those drivers had better all own houses with attached garages.
    - greglindahl 7y ago

jwilk 7y ago

For a moment I thought it's going to be about car washing.