One alternative is hydrogen. Hydrogen fuel cell technology isn’t perfect, with a loss of about 20-30% IIRC
You don’t recall correctly: The efficiency of Hydrogen, from solar cell to the wheels is 26%. Electrolysis is highly inefficient and compression and chilling of hydrogen is very energy intensive. Meanwhile, EVs are at 70%.
You are right that batteries kinda suck due to their energy density. However with EVs you can buy today you can still commute every day without noticing any major difference to an ICE car. You can also do long road trips, even in a small car, albeit slower. (Source: did both)
If you are looking at the pure engine efficiency, we are now looking at >97% for most EV motors (class IE4). However, the point of the entire transition away from fossil fuels is preventing or delaying climate collapse. For this purpose lowering emissions and reducing energy use go hand in hand, hence the overall efficiency is critical.
Hydrogen is less strongly bound to Carbon than Oxygen, however in this process we produce more CO2 again.
There is a theoretical upper bound for the efficency of water electrolysis, depending on the temperature. While current electrolyzers can surely be improved, since we are already making electricity, we might as well use it directly. Some applications (aircraft, rockets, …) need the higher energy density of chemical fuels. But: Working with liquid or gaseous hydrogen is terrible: Cyrogenic liquids are not easy to handle, let alone store. Hydrogen will embrittle any metal exposed to it and when inadvertenly mixed with air forms a highly explosive gas. Even the rocket people try to avoid using hydrogen unless they really need the ISP.
So far we have seen EV batteries not degrade a lot due to good BMS. For most cars the battery will last at least 10 years before performance is seriously impacted and even then the battery can be reused for storage (home or grid scale). Most EVs have >40kWh batteries, homes usually need 5-10kWh storage. So one chewed up EV battery could be reused for multiple stationary battery systems.
I do agree that current battery tech is… not great. Having less spicy cells that are easier to recycle or recondition would be a massive gain and more research needs to be a core focus. However Li-Ion and LiFePo are already good enough to work for most people most of the time. Pair this with a lot of wind and solar energy generation and you have mostly sustainable traffic. This can be done right now and it has to be done right now. I argue a lot against hydrogen because it seems like a technology that is not there yet and allows many old players in the energy market to delay a transition which is not beneficial to them.