>>12570643Hard to say. Lithium has one of the highest electromechanical potentials, so chemically, it can't really be beat. However, one of the major draw backs is that the anode is majorly carbon in order to provide stability and prolong the lifetime of the cell to usable levels. There's about 10 times more carbon than lithium. A company recently made a claim to have developed a new battery construction that removes most of the carbon, which would improve the energy density tremendously, but so far it's just a claim.
To answer your question, yes, Li is currently the best with no realizable alternative. We could theoretically improve Li batteries, but to have something different would require a different methodology of energy storage.
