A facile pre-assembly strategy toward grain boundary-induced-graphene based hybrid frameworks with high capacitance

Abstract

Three-dimensional graphene based hybrid frameworks (GHFs) prepared by chemical vapor deposition (CVD) have shown extraordinary promise for energy-storage but are usually limited by the lack of facile and efficient preparation strategies. Herein, a facile and general strategy is developed to synthesize near-nanoporous GHFs via mechanically-assisted pre-assembly and CVD processes. Functional nanomaterials (FNMs) are pre-filled into copper-nanopowders (CuNPs) as semi-sacrificial templates of CVD-graphene. A grain boundary-induced-graphene growth mechanism is demonstrated: during CVD process, graphene preferentially nucleates/grows along the abundant grain-boundaries formed by the fusion of CuNPs. Meanwhile, these FNMs are firmly combined with graphene-frameworks by π-π interactions and/or van der Waals forces, thus GHFs are constructed. Furthermore, two typical GHFs containing single-wall carbon nanotubes and molybdenum disulfide (defined as G/SWNT and G/MoS2, respectively) are used as freestanding supercapacitor-electrodes: Both GHFs exhibit high capacitance (232.4 F g−1 for G/SWNT and 331.1 F g−1 for G/MoS2) and impressive stability (96.62% capacitance-retention after 10,000 cycles for G/SWNT; 92.18% retention after 5000 cycles for G/MoS2), which due to the firmly combination of active FNMs and near-nanoporous graphene-frameworks by our strategy. These results suggest that our pre-assembly strategy can prepare various GHFs with excellent energy-storage performance.