 More recently, functional paper batteries have been demonstrated, where a lithium-ion battery is integrated on a single sheet of paper through a lamination process as a composite with Li4Ti5O12 (LTO) or LiCoO2 (LCO).The paper substrate would function well as the separator for the battery, where the CNT films function as the current collectors for both the anode "and" the cathode.These rechargeable energy devices show potential in RFID tags, functional packaging, or new disposable electronic applications.