First you read the chart wrong the volumetric energy density of compressed hydrogen is lower, liquid hydrogen had it’s own set of huge problems. Volumetric issues are huge for aircraft as larger volume means more drag which reduces the utility of all that energy.
Anyway, your comparing hydrogen ignoring the loss factor of engines, and the weight of fuel tanks so the useful energy density is much lower. “High-pressure tanks weigh much more than the hydrogen they can hold. The hydrogen may be around 5.7% of the total mass,[19] giving just 6.8 MJ per kg total mass for the LHV” At an overly generous hypothetical engine efficiency of * 50% that’s ~= 3.4 MJ per kg.
New chemistry is hardly a dream there are a huge range of battery chemistries out there with many under active development that beat current lithium ion batteries. Aluminum isn’t quite up to the hype, but it is very promising for aircraft.
> First you read the chart wrong the volumetric energy density of compressed hydrogen is lower,
No, you read the chart wrong: Hydrogen gas at atmospheric pressure - as in not compressed - has worse energy density by volume. Hydrogen at 700 bar has ~5x the energy per liter than lithium ion batteries at liquid hydrogen 10x. And all of these have energy densities by mass that are 100x better than lithium ion battery or more.
> New chemistry is hardly a dream there are a huge range of battery chemistries out there with many under active development that beat current lithium ion batteries.
Such as? You gave the example of aluminum, but as you point out they have problems that inhibit practical use: namely corrosion of electrolytes. The point remains: lithium ion is the best battery chemistry we've yet found and even it is far, far from up to the task of powering an aircraft.
Anyway, your comparing hydrogen ignoring the loss factor of engines, and the weight of fuel tanks so the useful energy density is much lower. “High-pressure tanks weigh much more than the hydrogen they can hold. The hydrogen may be around 5.7% of the total mass,[19] giving just 6.8 MJ per kg total mass for the LHV” At an overly generous hypothetical engine efficiency of * 50% that’s ~= 3.4 MJ per kg.
New chemistry is hardly a dream there are a huge range of battery chemistries out there with many under active development that beat current lithium ion batteries. Aluminum isn’t quite up to the hype, but it is very promising for aircraft.