Battery-capacitor asymmetrical systems, using Zn as battery-type negative electrode and CNT as capacitor-type positive electrode are developed with both aqueous and solid polymer based electrolytes. The devices combine the merits of both electrodes: The Zn electrode contributed 1.6 V cell voltage, while the CNT electrode results in fast and reversible capacitive behavior. An all-solid asymmetrical system is demonstrated using a PVA-TEAOH polymer electrolyte and exhibit high power capability and long cycle life. The good capacitive behavior, excellent stability upon 10,000 cycles of charge and discharge, and high cell voltage suggest a promising system for thin film solid energy storage applications. (C) 2017 Elsevier B.V. All rights reserved.