> There are some kinds of battery that only work at those temperatures - molten salt batteries. Used on earth for a few types of missile and some grid batteries.
Not an expert in batteries but Wikipedia says molten salt batteries provide high amount of power only for a short period of time:
> Once activated, they provide a burst of high power for a short period (a few tens of seconds to 60 minutes or more), with output ranging from watts to kilowatts.