Chemical and Structural Analysis of Carbon Materials Subjected to Alkaline Oxidation

Abstract

Redox species such as transition metals may, unknowingly, integrate carbon materials that are produced (or supplied) for the assembling of electrodes in batteries, supercapacitors, and fuel cells. The extent to which these species alter the electrochemical profile of carbons and affect the performance and/or degradation of energy storage systems is still not fully appreciated. Alkaline oxidation (or fusion) is a promising approach to disintegrate nanocarbons for the subsequent study of their chemical composition by routine analytical tools. In this work, three commercial carbon powders, relevant for electrochemical applications and bearing varied textural orientation (point, radial, and planar), were selected to evaluate the versatility of fusion as a pretreatment process for elemental analysis. Additionally, the interaction of the flux, a lithium borate salt, with the carbons was elucidated by examining their post-fusion residues. The degree of structural degradation varied and, generally, the doping with Li and/or B (whether substitutional or interstitial) was low to nonexistent. With future developments, fusion could become a relevant pretreatment method to analyze the composition of carbon materials, even when complex mixtures (e.g., cycled battery electrodes) and larger batch scales are considered.