Electrochemical Analysis of Lithiated Graphite Anodes

Abstract

Theoretical calculations are compared with well-controlled experiments conducted on a porous, graphite-based, lithiated-carbon electrode. The interpretation of the electrode behavior is facilitated by the use of a reference electrode in a cell that maintains a substantially uniform current distribution. A solvent-casting procedure for constructing graphite anodes, employing a hydrocarbon [poly(ethylene+propylene+norborene)][poly(ethylene+propylene+norborene)] binder is implemented. Nonlinear diffusion of lithium intercalate within the host carbon particles is considered; previously published concentration-dependent diffusion-coefficient data are employed for the lithium intercalate species. Other important resistances result from ionic diffusion and migration within the solvent phase, interfacial reaction at the surface of the carbon particles, and electron transport within the solid phase. Calculations are used to assess the impact of particle shape and the nature of the carbon precursor. The overall analysis indicates that interfacial resistance plays a dominant role in limiting the available capacity at high rates of current passage. © 2003 The Electrochemical Society. All rights reserved.