A Nanostructured Honeycomb Carbon Anode

Abstract

We have been investigating a general template-based method for preparing nanostructured Li-ion battery electrodes. We have shown that these nanostructured electrodes have improved rate capabilities relative to thin-film control electrodes composed of the same material. Improved rate capabilities are observed because the high-rate capacity obtained from -insertion materials is limited by slow solid-state transport in the electrode material, and the nanostructured electrodes decrease the distance that must diffuse in the solid state. We describe here an alternative type of nanostructured electrode material, a honeycomb carbon anode that consists of a thin carbon film containing an ordered array of monodispersed nanoscopic pores. This honeycomb carbon anode shows a low-rate discharge capacity of 325 mA hg−1, close to that of graphite. At high discharge rates (10 C), the honeycomb anode, delivers 50 times the capacity of a thin-film control anode that did not contain the honeycomb of nanopores. Improved rate capabilities are obtained because penetration of solvent and electrolyte into the pore structure of the honeycomb anode insures that the distance must diffuse in the solid state is smaller than in the thin-film control electrode. © 2003 The Electrochemical Society. All rights reserved.