Low-Temperature Plasma Substrate-Free Production of Graphene from Natural Gas

Graphene nanomaterials offers multiple technical benefits in printed electronics, structural materials, displays, capacitors, high-performance computing applications, and especially energy storage where researchers have reported a five-fold increase in the charge rate of a graphene- enhanced Li-ion battery. Historically, industrial production of graphene nanomaterials has been hindered by the need to use substrates or catalysts involving costly or impractical separation methods, which prevent the economical scaling of production. Conventional methods have low yields, limited throughputs, and/or high-energy requirements, which limit production rates (0.2 mg/min) and translate into extraordinarily high costs ($450-$4,500 per kg). An opportunity exists to utilize low-temperature microwave plasma for the substrate-free production of graphene platelets using process conditions known to promote single-atom thick carbon formations. This opportunity will be addressed by using an innovative low-temperature microwave plasma process operating at atmospheric pressure without laboratory-style plasma dielectric containment or substrates to produce graphene nanoplatelets with virtually zero process CO2 emissions, lower energy requirements, lower operating costs, and lower capital costs than the existing state of the art. Phase I seeks to determine the temperature range wherein conversion towards desired graphene nanomaterial is unrestricted by energetic barriers. Consistent with predictive model development, simulations will be performed to determine the temperature-time profile of the reacting flow, and these profiles will be compared to graphene nanomaterial yield and quality for optimization of process conditions. The project will deliver an innovative low-temperature microwave plasma process for converting natural gas into graphene nanomaterials, overcoming the technical and economic limitations of conventional methods. Presently, the extraordinarily high cost of conventional methods of producing of graphene nanomaterial is the single greatest factor preventing numerous commercial sectors from enjoying the benefits of these otherwise highly desired and versatile materials. By avoiding the labor and capital intensive steps of conventional production, an innovative low-temperature microwave plasma process can be scaled to production rates unachievable by conventional methods and can be deployed with less capital and at significantly lower operating costs. With a two order of magnitude reduction in production cost promised by low-temperature microwave plasma, graphene nanomaterial use will be rendered economical in multiple industries where the use of graphene has hitherto been cost-prohibitive.