No, that's not really a thing at all. Li-ion batteries burn because they contain a combustable electrolyte. The initial explosive reaction doesn't have that much to do with the energy in the batteries. The long term reaction is related to the energy in the battery, but only because the electrolyte burned off letting the anode and cathode short out.
There are plenty of demonstrations of solid state li-ion batteries that have way higher power density, but that can be cut in two without any explosive reaction at all.
The challenge with most of these is cycle life btw.
In the extreme case, you can get insanely high energy density out of aluminum-air batteries, but as far as I know they're perfectly safe.
Making a safe battery with high energy density is easy. Getting all the other parameters right is hard.
No, this isn't the problem. The problems are weight, volume, energy density and cost, and the fact that there's no single catch-all battery solution w.r.t. dis/charge rates, capacity, and the aforementioned values. Safety, while very important and somewhat costly (engineers time--mechanical and certificates), is something the big battery companies understand very well.
> The more powerful your battery, generally the more dangerous/flammable/explosive it is when it fail
There's a concept called single-cell isolation that basically obviates this.
The higher retrieval efficiency by definition makes an equivalent volume of batteries lower energy density and thus safer than an equivalent amount of fuel. If you need to extract X energy at 25% efficiency you need to store 4X. If you can extract X energy at 70% efficiency you only need to store 1.25X. Both could wind up exploding but you want the one with only 1.25X the stored energy not the one with 4X.