An assembly and interfacial templating route to carbon supercapacitors with simultaneously tailored meso- and microstructure.

The development of facile strategies for simultaneously tailoring robust pore hierarchy and integrated microstructure in carbonaceous materials is critical for the efficient multi-scale control of fluid, molecular/ionic, and charge transport in applications spanning separations, catalysis, and energy storage. Here, we synthesize three-dimensionally ordered hierarchically porous carbon powders by the assembly of glucose with silica nanoparticle (NP) building blocks of sacrificial NP-crystalline templates. Such template-replica co-assembly offers an attractive alternative to conventional nanocasting by circumventing the need for sequential template pre-formation and infiltration-based replication. In addition, interfacial templating leads to hierarchically structured carbons with tunable mesopore volumes (as high as 5.8 cm/g). Beyond mesostructuring, we identify the template-replica interface as a potentially versatile, but generally unexploited handle for tailoring the sp hybridized carbon content in the porous replicas under mild carbonization conditions and without specific chemical activation or catalytic graphitization. This multi-scale (meso-micro) templating offered by a single template expands the potential versatility of nanocasting for the hierarchical structuring of replica materials. Application of the resulting carbons as electrochemical double layer capacitors (EDLCs) demonstrates the combined benefit of simultaneously tailored pore hierarchy and tuned microstructure upon ion and charge transport, respectively, yielding supercapacitors achieving specific capacitance as high as 275 F/g in aqueous electrolyte (HSO) and retention of 90% up to current densities of 10 A/g.