Very expensive UAVs use lithium polymer battery packs with continuous discharge rates on the order of 80C and above. To get higher energy density, look for lithium ion battery packs or lipo packs that reduce discharge rates to trade off for long-term storage capacity.
Compare to the discharge rate vs. energy density tradeoffs of plug-in hybrid EVs versus battery-only EVs: A Chevy Volt PHeV has a 16 kWh pack and 87 kW motor, a Chevy Bolt has a 65 kWh pack and not a 65/16x87=350 kW motor but 149 kW.
Compare to the discharge rate vs. energy density tradeoffs of plug-in hybrid EVs versus battery-only EVs: A Chevy Volt PHeV has a 16 kWh pack and 87 kW motor, a Chevy Bolt has a 65 kWh pack and not a 65/16x87=350 kW motor but 149 kW.