RE:RE:RE:RE:FrankYes lithium batteries store energy, they don't generate it. In fact you don't create energy. You transform it from one form to another like the chemical energy in natural gas to fire a thermoelectric plant to produce electricity to store in batteries.
So we need to be talking about what stores the most energy per unit mass. Nature has already figured it out. Hydrocarbons are essentially stored solar energy. Phytoplankton to kerogen to hydrocarbons create over millions of years by biological and geological natural processes. In fact hydrocarbons have 60 times the energy density (available useful energy per kilogram) than that of a lithium battery. The only thing that has more energy density is the binding energy in a uranium nuceus.
Some humans are so stupidly arrogant to think that humans can come up with anything that can store energy better than nature can. Nature created us. We did not create nature.