Lithium Insertion in Disordered Carbon−Hydrogen Alloys: Intercalation vs Covalent Binding

Disordered carbons obtained by pyrolyzing organic solids at T ≤ 700 °C retain substantial residual hydrogen and exhibit surprisingly large capacities for Li uptake in electrochemical cells. Using semiempirical computer simulations, we show that the high capacity is partially attributable to Li binding on H-terminated edges of hexagonal carbon fragments, with local geometries analogous to the stable isomer of the organolithium molecule C 2 H 2 Li 2 . These results can be tested experimentally by vibrational spectroscopy and have implications for further developments in Li-ion rechargeable battery technology.