Layer disorder in carbon anodes

Abstract

Inter- and intra-layer disorder in a representative hard carbon derived from epoxy novolac resin at 1000°C have been investigated by comparing both the elastic structure factor S( Q) and radial distribution function obtained from pulsed neutron time-of-flight measurements with calculations from simple hypothetic systems with specific disorder characteristics. The spatial relationship between these building blocks, planar graphene fragments with length scale of 1 nm, is probed in terms of inter-layer alignment and intra-layer connectivity. Coupled with the density of dangling bonds obtained from ESR and residual hydrogen concentration, these simulations provide sufficient information to construct an overall model of the carbon structure. Of special interest is the physical origin of the ubiquitous broad (002)-like reflection frequently interpreted as that from layers with a uniform interlay spacing (d 002) It is found to be directly related to the misalignment between layers with an average interlayer spacing as that in crystalline graphite (3.35 Å).