It's physics. Compare capacitors (high power, short duration) with batteries (low power, long duration). The fundamental concept of both is trapping electrons and the higher energy those electrons have, the more inclined they are to escape entrapment. This tradeoff is inescapable. Batteries have not improved much over the last 20 years (latest breakthrough was lithium-ion). They've also not improved much in terms of energy density nor cost (about 100% since proof of concept). Li-ion was coming down in $/kwh but now it's going up again because of excess demand versus supply.
Meanwhile, look at Toyota Mirai between the first generation and second generation. Everything about it improved by double digits (20% more power, 15% more hydrogen capacity, 30% more range, etc.) in the space of six years. Toyota isn't even trying that hard because it's such a low volume product.
It improved so much because hydrogen hasn't received nearly as much R&D as batteries and li-ion in particular, so there's a lot more low-hanging fruit to be plucked from the hydrogen research tree. Those impressive increases are going to drop off fast once all the easy wins are won.
That's not to say that it's not worthwhile to invest into hydrogen R&D - the more options we have to get away from fossil fuels, absolutely the better - but writing off battery tech in favour of hydrogen is certainly premature.
So, I'm not sure if you guys are trolling, revising history, or simply have such a limiting view that it's funny. I think it's time to reconcile.
That is to say, batteries based on electronegativity stretch back to ancient Egypt. Lithium ion batteries are also batteries that store energy through electronegativity...and literally began life as canopic jars that held ionic fluids. The "much more research" here is a vague and poorly defined transient interest in a specific chemistry of electronegative chemistry...which itself has mostly been focused on the terminal construction to allow for increased charging rates and increased battery life before the chemical make-up of these batteries starts to degrade.
Remember, there are tutorials out there regarding the common sulfuric acid-lead batteries that have been around basically as long as electrical power has been commonly adopted.
Now, likewise, hydrogen is ancient. Did nobody ever think to look at the primary source of hydrogen, electrolysis, and do any sort of thinking? What about the isolation of excess hydrogen from the petroleum distillation process used on the Hindenburg?
Let me be even less obtuse, in chemistry there are an entire branch of reactions which are called electrolytic...most of which separate elemental gasses from compounds utilizing either chemical reactions or outside energy inputs.
Now that we've laid waste to the history argument, why do you not see hydrogen vehicles out on the road? Why was Toyota able to do it in very limited demonstrative form? Why am I so angry about the above...when it's history?
Let me answer these posed questions in order.
1) Why aren't hydrogen vehicles on the road?
Let me start by stating that energy density is the largest single factor here. The reaction in question is 2 H2+ O2 = 2H2O. You don't carry around the O2, just like the octane reaction. That, for the record, is 2 C8H18 + 25 O2 = 16 CO2 + 18 H2O. If you do some basic chemistry on this, you basically need a bunch more hydrogen to create the same energy as a single octane molecule...but the problem is in storing that hydrogen.
Let me now state some more basic chemistry. In most materials solids are more dense than liquids, liquids and more dense than gasses, and that elemental hydrogen follows these rules. Thus, an elemental gas needs to be under immense pressure to both have the amount of atoms to rival a simple hydrocarbon combustion reaction and to store that energy in the same volumetric space.
Did you catch that? I hope you did...because the operative words there were that hydrogen gas needs to be stored under immense pressure and in great quantities to rival the much cheaper and more stable technology of a tank full of hydrocarbons.
This is to say nothing of the storage, leakage, and crash safety of the technology. Hydrogen atoms are tiny...so they have the tendency to leak very easily. Imagine not running your car for a few days...and having 20% of the fuel gone. Imagine storing that car inside a garage...and the leaked hydrogen being a stupidly high risk for any spark anywhere to cause a detonation. Now if that wasn't enough, imagine an accident. Hydrogen tanks represent an immediate risk of explosive decompression, a less immediate risk of detonation by spark, and finally a risk of kinetic shock should they decompress without the other bad things happening. All of this is basic physics.
2) Why was Toyota able to do it?
Well, Toyota retrofitted a common car with a hydrogen power cell. Really easy, and really expensive. Store the hydrogen, burn through it immediately after fueling, and never deal with the longer term issues. Cool.
Why did they have double digit break-throughs on performance? Well...math. If you look at current technologies your car has a fuel-air ratio, and a compression ratio. The earliest cars did a very bad job with this...and were inefficient. We've had hundreds of years to refine the input materials (which hydrocarbons), and the compression ratios (remember tetra-ethyl lead...that leaded gas was introduced to raise compression ratios before auto ignition) to make engines run efficiently.
Toyota had the same place to start, and the same refinements to make. In the business, we call this low hanging fruit for optimization.
So...Toyota ignored the fundamental storage issues, by not having this in a consumer vehicle. They showed vast improvements...by optimizing reactions. They did all of this without worrying about a consumer price tag...because this was a research project rather than a production vehicle. Once you do all that math, it's easy to see why they might not have as many issues demonstrated to the public...and despite this never get close to a consumer release.
So....what is the way forward? Well, that's hard to say. There are two hydrogen technologies that matter. That'd be combustion as a stop-gap replacement to hydrocarbons, and a means to directly convert elemental hydrogen and oxygen to electrical potential via a membrane transfer. Basically, instead of blowing up the hydrogen and getting expanding gas that converts to linear mechanical potential energy you get straight electrical potential energy.
The thing about both of these technologies is still the thing that we started with. How do you store the immense amount of hydrogen safely? How do you access it? How do you make it cheap? How do you make it safe?
These are not new questions. Humans have spent hundreds of years trying to make hydrogen safe. Hundreds more have been spent trying to store energy. The failure here is physics, but it's not a magically recent failure. It's literally hundreds of years of failures, improvements, and break-throughs. Ignoring all of that, and pretending that some sort of short term break-through is going to make anything more viable, is a joke.
As an aside, it may be possible to fix the storage issue. If you can do that, then you'll be fabulously wealthy. Good luck though...people have spent literal lifetimes looking for that answer. I find it frustrating when people continue to spout the nonsense that all of the problems will be fixed in our lifetimes...completely disregarding the lifetimes already spent on this issue. Maybe instead of dreaming, we educate ourselves. The past is a prelude to the present and future...and there's a reason things like rigid airships are a thing of fiction...rather than non-fiction.
