The local structure of several disordered carbons, obtained from radial distribution function analysis of elastic neutron scattering data, consists of small isolated graphene fragments. The effect of residual hydrogen which presumably saturates the dangling bonds in low-temperature pyrolyzed materials was studied by inelastic neutron vibrational spectroscopy and computer modelling of lithiated polyaromatic hydrocarbons. We discuss the possibility of exploiting the high-pressure crystal phase LiC2 in primary batteries, by demonstrating that trace baron substitition greatly enhances the (meta)stability of this phase at atmospheric pressure.