Scalable synthesis of zeolite-templated ordered microporous carbons without external carbon deposition for capacitive energy storage

Abstract

Abstract Zeolite-templated carbons (ZTCs) have unique ordered microporous structures composed of 3-dimensionally connected graphene nanoribbons and buckybowl-like frameworks. ZTCs can exhibit extra-large surface areas, narrow micropore size distributions, and electrical conductivity, which make them promising for adsorption, catalysis, and energy storage. However, the synthesis of ZTCs still remains a great challenge when the synthesis scale is larger than just a few grams. Carbon deposition within narrow zeolite micropores is diffusion-limited, and unwanted dense carbon layers are often deposited at the external surface of zeolite, substantially diminishing ZTCs' structural properties and performances in various applications. In this study, we conducted the large-scale synthesis of ZTCs (>80 g) in a bubbling fluidized bed, which enables efficient mass/heat transfer. Compared to conventional synthesis in a fixed bed, ZTCs with superior structural properties could be synthesized in much shorter time. The resultant ZTCs showed ordered microporous structures with large surface areas (~3000 m2 g−1) and microporosity (~1.1 cm3 g−1). Most importantly, these ZTCs were free of undesirable external carbon deposition, which greatly diminishes the mass transfer of guest molecules (e.g., electrolytes) into the micropores. As a result, the ZTCs showed superior electrical double-layer capacitance compared to those synthesized in a typical fixed bed.