There are 1.5V AA li-ion batteries on the market. I bought a few to power children's toys and they have comparable capacity to alkaline batteries. At high currents they actually perform better.
Cost is about 10x that of their non-rechargeable brethren, but obviously there's return on that investment.
Cost is about 10x that of their non-rechargeable brethren, but obviously there's return on that investment.