Controlled Preparation of Interconnected 3D Hierarchical Porous Carbons from Bacterial Cellulose-based Composite Monoliths for Supercapacitors
The controlled design and synthesis of porous carbons with anticipated microstructures and morphologies, and high specific surface area (SSA) have been focused on supercapacitor development. Here, hierarchical porous carbons (HPCs) with interconnected three-dimensional morphology derived from a natural-based bacterial cellulose (BC) composite have been successfully prepared by thermally induced phase separation of poly(ethylene-co-vinyl alcohol) (EVOH) and subsequent carbonization/activation. The SSA and porous architectures can be controlled by fine-adjusting preparation conditions such as the precursor morphology and structure, activator dosage and activation temperature, and the relationships between the super-capacitive properties and the SSA and pore size distribution have been further investigated. The obtained porous carbon material possesses a hierarchical porous structure with moderate micropores, favorable mesopores, interconnected macropores, a high SSA of 2161 m2 g−1 and a maximum oxygen-dopant content of 9.99%, enabling increase in the active materials utilization efficiency and wettability. Due to the synergistic effects of these features, the obtained porous carbon electrode used in a supercapacitor shows a high speciﬁc capacitance of 420 F g−1 at 0.5 A g−1, excellent rate performance with 75% capacitance retention at 20 A g−1, and good cycle stability with ∼96.1% retention even after 10,000 continuous charge-discharge cycles at 5 A g−1. Additionally, the assembled supercapacitor based on the porous carbon displays a moderate energy density of 20 W h kg−1. The good electrochemical performance and facile effective synthesis of bio-derived carbon materials with tunable porous structures indicate promising applications in supercapacitors.