JTR Library has portable batteries with various types of cables to ensure that you never loose power on your phone. Portable Batteries and cables can be checked out for 5-hours. You can leave the library with these items but they must be returned to the JTR library.

Item Loan period
Lightning to USB cable 5-hours
Micro USB to USB cable 5-hours
USB-C to USB cable 5-hours
Portable Battery 5-hours
PC Chargers 5-hours
Apple 85W MagSafe 2 Power Adapter 5-hours
MagSafe to MagSafe 2 Converter 5-hours
Apple 87W USB-C Power Adapter 5-hours