Answer:
the order in which the sentences should appear is 4, 2, 3, 1
Explanation:
That means that the correct order should be;
"A storage battery is a relatively efficient way of storing energy.
However, the most challenging technical problem is to achieve substantial increases in the quantities of electrical energy that can be stored per unit weight of the battery.
The overall process yields about 70% of the electricity originally put into the battery.
If such improvements could be achieved, the consequences would be significant for many different applications."
Choosing this particular order allows the reader to easily understand;