The utilization of MnO₂ nanowire arrays for future light weight energy storage devices is investigated here. One of the more specific questions this work looks to answer is: Can ultra high density arrays of MnO₂ nanowires really be used to create future flexible micro-supercapacitors with high energy density, high power density, and long cycle lives? This research investigates the energy storage properties of dense arrays of solely MnO₂ nanowires and synergistic MnO₂ nanowire composites consisting of two or more materials/architectures, where the composite materials are able to offset some of the detrimental intrinsic properties of the MnO₂ nanowires. Accordingly, a complete flexible supercapacitor device was prepared utilizing a coaxial MnO2/poly (3, 4-ethylenedioxythiophene) (PEDOT) core/shell nanowire array cathode with a PEDOT nanowire array anode. This material demonstrated metrics considerably better than current devices even while being flexed. In addition, a hierarchical MnO₂ nanofibril/nanowire array was synthesized by transformation of a bare MnO₂ nanowire array. This material was investigated for its supercapacitor properties while altering the parameters of its nanowire and nanofibril architectures. Finally, MnO₂ nanowires were investigated for their charge storage mechanism using ICP-AES to detect Li ion to Mn ion ratios during the charging and discharging process. Their charge storage process was found to differ depending on whether the electrolyte solvent used was aqueous or organic. These projects all help advance energy storage devices well beyond their current status as bulky, heavy energy sources toward their prospective use as light weight, flexible, micro- power sources.