Structural characteristics and electrochemical properties of non-graphitizable carbons were investigated. The carbons were obtained by heat-treating the oxidized graphitizable carbon precursors with various molar ratios of aromatic compounds and cross-linking agent. The discharge profiles of the non-graphitizable carbons heat-treated at 600 degrees C had one plateau discharge region at 1.0 V vs. Li/Li+, which is similar to graphitizable ones heat-treated at the temperature. However, the discharge profiles of the non-graphitizable carbons heat-treated above 800 degrees C exhibited two plateau discharge regions at 0.2 and 1.0 V vs. Li/Li+. The discharge capacities of the non-graphitizable carbons increased with an increase of cavity volume, which was controlled by molar ratios of aromatic compound and cross-linking agent. The structural parameters proposed were measured to compare with each other, and it was found that they showed good correlation.