Energy storage devices using spinable CNT sheets

Our focus is on designing and synthesizing nanostructured materials having high specific capacitances. To achieve this, we have electrodeposited ultrathin films and/or nanoparticles of manganese oxides (MnOx) onto sheets of carbon nanotubes (CNTs) using either the linear potential sweep or potentiostatic methods. The morphology and electrochemical properties of the resulting composites depend on the amount of MnOx deposited and deposition conditions. The best composites obtained to date have large specific capacitances (C_sp ≤ 1250 F/g), high charge/discharge rate capabilities, and excellent cyclic stability. High performance composites result from both the enhanced surface area and enhanced electron-transport capabilities of MnO_x nanoparticles as well as the superior conductivity of the CNT sheets. Related composites are envisioned as electrodes for lithium batteries and super-capacitors.