Computational, electrochemical and (sup 7)Li NMR studies of lithiated disordered211 carbons electrodes in lithium ion cells

摘要

Disordered carbons that deliver high reversible capacity in electrochemical cells211u001ehave been synthesized by using inorganic clays as templates to control the pore 211u001esize and the surface area. The capacities obtained were much higher than those 211u001ecalculated if the resultant carbon had a graphitic-like structure. Computational 211u001echemistry was used to investigate the nature of lithium bonding in a carbon 211u001elattice unlike graphite. The lithium intercalated fullerene Li(sub n)-C(sub 60) 211u001ewas used as a model for our (non-graphitic) disordered carbon lattice. A 211u001edilithium-C(sub 60) system with a charge and multiplicity of (0,1) and a 211u001etrilithium-C(sub 60) system with a charge and multiplicity of (0,4) were 211u001einvestigated. The spatial distribution of lithium ions in an electrochemical cell 211u001econtaining this novel disordered carbon material was investigated in situ by Li-7 211u001eNMR using an electrochemical cell that was incorporated into a toroid cavity 211u001enuclear magnetic resonance (NMR) imager. The concentration of solvated Li(sup +) 211u001eions in the carbon anode appears to be larger than in the bulk electrolyte, is 211u001esubstantially lower near the copper/carbon interface, and does not change with 211u001ecell charging.