Tortuosity of Binder-Free and Carbon-Free High Energy Density LiCoO₂ Electrodes for Rechargeable Lithium-Ion Batteries

Abstract

Conventional electrodes, by volume, contain a large amount of electrochemically inactive material such as binder and carbon. This lowers the overall capacity of a battery and makes it difficult to realize high volumetric energy. Researchers have been actively pursuing methods which will enable the fabrication and full utilization of thick electrodes (≥200µm) with a minimal amount of inactive material. One approach which has emerged is to fabricate thick sintered electrode structures which are free of binder and carbon. However, these structures do not adhere to conventional assumptions about tortuosity. This paper aims to correlate John Newman’s macrohomogeneous porous electrode model to thick high energy density, carbon-free and binder-free sintered electrode samples fabricated at PARC. We examine how assumptions about tortuosity affect model predictions of capacity. Our efforts focus on understanding the model parameters which can be used in Newman’s existing model without modification to the underlying equations.