Microencapsulated Carbon Black Suspensions for Restoration of Electrical Conductivity



Robust microcapsules are prepared with carbon black suspensions high in solids loading (up to 0.2 g/mL) for electrical conductivity restoration. Oxidized carbon black is rendered more hydrophobic through surface functionalization with octadecylamine by two different methods. Functionalization significantly improves dispersability and suspension stability of carbon black in hydrophobic solvents such as o-dichlorobenzene (o-DCB), enabling encapsulation by in situ emulsion polymerization. Upon crushing, microcapsules containing functionalized carbon black (FCB) suspensions exhibit significant particle release relative to microcapsules filled with unfunctionalized carbon black. Release of carbon black is further enhanced by the addition of two types of core thickeners, epoxy resin or poly 3-hexylthiophene (P3HT). Full conductivity restoration (100% restoration efficiency) of damaged silicon anodes is achieved by crushing microcapsules containing FCB suspensions with P3HT. Hydrophobic surface functionalization of carbon black and the addition of core thickeners are both critical for achieving stable microcapsules capable of significant particle release and efficient conductivity restoration.