(358e) Electrosprayed Scalable 3D Graphene-CNT Electrodes for Li-Ion and Fuel Cell Applications

Lithium-sulfur batteries (LSB) and advanced lithium-ion batteries (LIB) demonstrate promise as the next generation energy storage and conversion (ESC) technology especially as it pertains to wearable technology and electric vehicles. Although LIB dominate the battery market (>90%) due its reliability, long cycle life, and market maturity, alternative means of renewable energy must be discovered in order to reduce the cost of materials, dendritic issues at the solid-electrolyte interphase (SEI) layer, and limited charge capacity (~250 mAH h g^-1). The next generation of future batteries is the lithium-sulfur battery due its inexpensive cost ($0.25/kg sulfur), high theoretical energy density (2600 Wh kg^-1), and safety. How LIB and LSB systems incorporate into military applications such as drones and battery backs is what the interests the Army. However, LSB face many challenges before commercialization into wearable technology and electric vehicles due its fast capacity degradation, polysulfide “shuttling” effect, and short cycle life (<300 cycles). Carbon nanomaterials constitute an ideal miniaturized composite platform for integration with other solid-state electrode materials. Air-controlled electrospray has been recognized as an effective means of fabricating cathodes using a convective air jet flow that accelerates the drying and deposition process. This technique provides a uniform and well-dispersed coating onto the current collector while using low-cost commercial carbon nanomaterials in a matter of minutes. Currently, self-assembly is conducting using the bottom–up synthesis of 3D macrostructures using graphene and carbon nanotubes (CNTs) as building blocks. We demonstrate a novel, all-aqueous, and scalable 3D platform materials design process for the synthesis of carbon nanocomposite aerogels to serve as porous ultralightweight electrodes for the next generation energy storage and conversion applications. Specifically, the negatively charged surface functional groups on graphene oxide and oxidized CNTs will be the sites for electrostatic coordination of positively charged noble metal cations and polyelectrolytes from aqueous solutions. This enables the incorporation of carbon nanomaterials with any polyelectrolyte and noble metal nanostructures with precise connection of each of the individual components while maintaining their unique properties in both LIB and LSB systems. Through a scalable air-controlled electrospray approach, we can develop hierarchical porous 3D nanocomposite cathodes comprised of carbon nanomaterials with any precious or noble metal nanostructures (Pt, Pd, Au, Ru, Ag, and Ru) and polyelectrolyte that demonstrate a synergistic network between the active materials, carbon materials, and metal nanostructures. Electrochemical techniques such as cyclic voltammetry, linear sweep voltammetry, galvanostatic charge-discharge, and impedance spectroscopy are used to determine the electrical and ionic conductivity, electrocatalytic activity, and supercapacitor performance of the aerogels as lightweight high-power and energy density electrodes.