A carbon-nanofiber glass composite with high electrical conductivity

TL;DR

This paper reports a method to produce highly conductive oxide glass composites using carbon nanofibers, achieving record electrical conductivity without altering the glass's mechanical properties, enabling new multifunctional applications.

Contribution

The study demonstrates the highest reported room-temperature electrical conductivity in bulk oxide glass composites via a novel glass-sintering process with carbon nanofibers.

Findings

Achieved 1800 S/m electrical conductivity in glass composites.

Theoretical model accurately predicts conductivity dependence on carbon loading.

Nanoscale analysis confirms a connected carbon nanofiber network.

Abstract

The use of oxide glasses is pervasive throughout everyday amenities and commodities. Such glasses are typically electrical insulators, and endowing them with electrical conductivity without changing their salutary mechanical properties, weight, or thermoformability enables new applications in multifunctional utensils, smart windows, and automotive parts. Previous strategies to impart electrical conductivity include modifying the glass composition or forming a solid-in-solid composite of the glass and a conductive phase. Here we demonstrate using the latter strategy the highest reported room-temperature electrical conductivity in a bulk oxide glass 1800 S/m corresponding to the theoretical limit for the loading fraction of the conductive phase. This is achieved through glass-sintering of a mixture of carbon nanofibers and oxide flint F2 or soda lime glasses, with the bulk conductivity further enhanced by a polyethylene-block-poly(ethylene glycol) additive. A theoretical model provides predictions that are in excellent agreement with the dependence of conductivity of these composites on the carbon-loading fraction. Moreover, nanoscale electrical characterization of the composite samples provides evidence for the existence of a connected network of carbon nanofibers throughout the bulk. Our results establish a potentially low-cost approach for producing large volumes of highly conductive glass independently of the glass composition.