This document provides an overview of paper batteries. It discusses the history of paper batteries, which were first developed in 2009. Paper batteries use carbon nanotubes and lithium compounds coated on paper as electrodes, with an ionic liquid as the electrolyte. They function similar to conventional batteries but have advantages of being lightweight, flexible, and able to work in a wide temperature range. While paper batteries are still more expensive than conventional batteries, their unique properties make them suitable for small, portable electronics. The document reviews the components, working, advantages and disadvantages of both paper batteries and conventional batteries.