Polymer-Derived Silicon Oxycarbide/Graphene Oxide Porous Ceramic Monoliths Obtained from Pickering Emulsions: Application as Active Electrodes for Lithium-Ion Batteries

The fabrication of porous ceramic materials is of great importance for various applications in energy, catalysis, filtration, and refractory applications. Achieving rational design of polymer-derived ceramics (PDC) with hierarchical porosity has been made possible with the use of porous agents, direct foaming, or replicates. However, these synthetic approaches often suffer from complexity and limited control over their desired porous architectures. In this study, we report an innovative method for preparing porous polymer-derived ceramic (PDC) monoliths by combining the preceramic polymer route and the Pickering emulsion method. The emulsions were prepared by using a SiOC precursor and stabilized with graphene oxide nanosheets modified with hexadecylamine. The effects of formulation on the final properties of Pickering emulsions were thoroughly studied, taking into account the emulsification process, emulsification rate, concentration of modified graphene oxide (GO), and DMSO/cyclohexane ratio. As a proof of concept, we have used the monoliths obtained as electrode materials for electrochemical energy storage in Li-ion batteries (LIBs), exhibiting higher specific capacities that are approximately 2 times higher than that of the graphite anode. Among the tested electrodes, the SiOC-GO-R16 (23%, 900 °C) electrode showed the best overall performance, displaying impressive insertion and extraction capacities of approximately 2399 and 1176 mAh g–1 at 50 mA g–1, respectively, in the first cycle. At 800 mA g–1, the charge capacity was 350 mAh g–1 after 175 consecutive cycles, accompanied by a Coulombic efficiency of 88%. Our approach offers a novel and efficient route to fabricate porous PDC monoliths with tailored properties and superior electrochemical performance compared to traditional PDC-based electrodes in LIBs and highlights their potential for advanced energy storage applications.