Lithium batteries are interesting because they store 200Wh/kg, vs. 40Wh/kg for lead. But they're dramatically more expensive, about 500€/kWh vs. about 100kWh/kg

Lithium batteries are interesting because they store 200Wh/kg, vs. 40Wh/kg for lead. But they're dramatically more expensive, about 500€/kWh vs. about 100kWh/kg for lead (difficult to compare precisely, due to different tolerances to deep discharge among others)