Power Bank, which shall proceed to implement it will not be a traditional, as implemented by the others, because we will improve it.
Improvement will be in use a pair batteries can be recharged from a 9-volt type
Step 1: Make a Connector to the Battery
As you show
Step 2: About the Batteries
.....These batteries can be found in electronics stores and if you did not find them to be used ordinary batteries
.those batteries can be remove them from power bank and then charge and installed again
...Regular batteries when emptied thrown out and buy other
..We'll connect the pair of batteries in parallel
A pair of batteries will make the best performance and can charge most mobiles.
.one battery may charge the mobile battery to half of its capacity .