Hidden Morphological Features in Organically Synthesized Porous Carbon Revealed through Analysis of Contradictory NMR Spectra

Abstract A new family of carbon-based materials named “Organically synthesised porous carbon” (OSPC) have proven to have exceptional properties as anode materials in lithium-ion batteries. Experimental X-ray photoelectron spectroscopy characterization has confirmed that the framework of OSPC-1 synthesized via two different synthetic routes, OSPC-1a and OSPC-1b, is based upon sp and sp3 carbon. Strangely, however, the solid-state NMR spectra for both OSPC-1a and OSPC-1b do not appear consistent with this model. Here, we show that a dense highly interpenetrated morphology based on sp and sp3 carbon can fully rationalize the solid-state NMR spectra of both OSPC-1a and OSPC-1b. We suggest that this structure is dominant, but that the porosity arises from a newly uncovered morphology with an open noninterpenetrated highly porous OSPC-1 framework structure best approximated by the topological features present in the dia, pts-c, and unc-c topologies. This impacts the conductivity and ion storage, properties of OSPC materials and so it is imperative that this is considered when designing new OSPC materials with targeted properties for potential applications.