DIY tubeless ESPECIALLY when using something like a tube between the rim and tire is a very, very bad idea.
Take a look as specifically designed tubeless tire & wheel systems and you will see a much more aggressive "hook" and retainer design to hold the bead onto the rim.
Taking a standard clincher tire rim and introducing some kind of "shim" between it and the tire is only asking for that bead to come off easier, especially at speed, and even if you just had low tire pressure that would be enough to unseat that rim.
Also, the tire designed for a tube isn't really going to hold air like it should, and will not have the side-wall strength it had with a tube inside, so your tire isn't going to handle well in turns, and will tend to roll more than flex making cornering potentially dangerous.
There are kits out there, but none really convert your wheel that is designed for tubes to work very well, the real answer is a wheel and tire designed for tubeless, but these wheels are going to be much stiffer and more difficult to take on and off, so in the end, if you're experiencing a lot of punctures, you're really not doing yourself any favors going tubeless IMO.
I tried to get a good picture of the cross section of a typical clincher rim VS a tubeless, and didn't find any, but I would STRONGLY recommend you to NOT try and make a tube rim work tubeless, you're just asking for trouble, especially at E-Bike speeds.
I just recently wrecked my bike simply because I forgot to check the air pressure, and with the big balloon tires I run (Big Apples & CST Cyclops), the front which happened to have a pin hole leak, and leaked out to about 5 or 10 lbs over-night before a long ride, rolled on me in a hard right corner, completely washing out the front-end, and luckily I wasn't hurt, or the bike to badly damaged (just some scratches).
Just imagine if I had something that would have given that tire and even easier way to come off the bead with a DIY tubeless system! I can only imagine (I regularly go 40MPH down a hill and cruise between 25-30 MPH) and there are a few tubeless set-ups out there, but not even one kit out there was even given an honorable mention in UBI's (United Bicycle Insitute) mechanics courses I have just completed, as they all tend to have various problems.
Mavic, Stans Tubeless and Shimano have some tubeless systems out with with purpose built wheels and tires if you want to go tubeless, but you're getting into a very high priced and specialized niche market, expect to pay a ton more for tires and the wheel sets.
Another thing I would mention, even if you manage to get something to hold pressure, and have no problems with the beads, what happens when you have to work on the wheel and get to the spokes to true the wheel?
IMHO, it's altogether a bad idea, just use better tubes/tires/tire strips or if you're getting regular punctures that would be plugged with slime, it looks like Dogman has had good luck with the automotive stuff.
Personally, the only flats I have ever gotten where huge holes that no slime would have helped with (1/4 soldering iron tip last time .. DOH!
) and I rarely have any trouble, I roll over glass, and other small debris regularly, using kevlar puncture resistant tires, No Flats flat strips and regular tubes.
This last flat was a faulty tube, it was holding air just fine before winter when I switched to my snow studs, and never thought to check it before reinstalling on my bike now that it's spring, one of the few times I ever forgot to check tire pressure with a gauge, I ended up wrecking lol!