Electrolysis from water to hydrogen, and its subsequent recombination are maybe ~60% each to be generous. Ltithium batteries have made good progress over the last decade. Lithium batteries, are ~90% efficient and are looking at a ~80% recharge in 5 minutes, some faster than that, a lifetime of thousands of charge/recharge cycles and a price in the hundreds of dollars per kilowatt hour. The future is likely PHEVs with a battery powered range of ~12 miles and recharging stations in most parking lots.