Dense Carbon Nanoflower Pellets for Methane Storage

Natural gas is a promising alternative transportation fuel over conventional gasoline because of its low harmful gas emissions and abundant reserves. The key challenge hindering its extensive use for this application has been a lack of materials that can store it in a “dense” form efficiently at ambient temperature. Herein, this work reports the development of high-performance dense carbon nanoflower pellets for on-board methane storage applications. Polyacrylonitrile pellets are prepared by taking advantage of the uniform polymer particle size obtained through the one-step free radical polymerization process. These polymer pellets can be readily converted to carbon pellets while preserving the densely packed structure. The obtained high bulk density and interconnected micro-, meso-, and macropores provide carbon nanoflower pellets with a record-setting bulk density (0.96 g cm–3), while having a surface area of 1077 m2 g–1. High methane storage capacities of 165 and 196 cm3 (STP) cm–3 are achieved at 35 and 65 bar, respectively. This work provides a simple method to prepare densely packed carbon pellets. Because the carbon pellets reported here can be readily prepared at a large scale, this work demonstrates a promising path toward the utilization of carbon materials for potential gas and energy storage applications.