Microporous carbons with a tunable morphology were fabricated via a low cost chemical activation route. Using these carbons as precursors, carbon polyiodide nanocomposites of various compositions were prepared by mechanochemical iodine incorporation. The effect of micropores and mechanochemical iodation on the structure, morphology, and electrochemical behavior of activated carbons was investigated using a host of characterization methods, including X-ray diffraction, small angle X-ray scattering, Brunauer-Emmett-Teller, differential scanning calorimetry, transmission electron microscopy, and Raman spectroscopy. Polyiodide formation and preferential micropore filling were observed in iodated carbons. The corresponding iodation-induced nonfaradaic and faradaic developments in modified carbons led to much improved gravimetric (similar to 39 mAh/g) and volumetric capacities (similar to 80 mAh/cm(3)). These microporous carbon-iodine nanocomposites have been studied focusing on the relative role of double-layer formation and faradaic pseudocapacitance to evaluate their possible use in hybrid capacitors and low voltage batteries. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3212851] All rights reserved.