What is Li-ion/Li-Polymer？

Lithium-ion (Li-ion) and Lithium-polymer (Li-Po) are rechargeable battery technologies using lithium compounds as the primary component for energy storage and delivery.

Simply Put:

Think of Li-ion/Li-Polymer batteries like reusable water bottles. You can fill them up (charge them), use the water (power), and then fill them again when empty.