In this work we investigate the electrochemical behaviour of two silicon oxycarbide (SiOC) glasses synthesized from the same starting precursor. In one case we perform pyrolysis in an Ar flow, while in the second case, the glass is synthesized under a CO₂ flow. The microstructural characterization of the glasses unambiguously demonstrates that the Ar-pyrolyzed material (SiOC–Ar) is a SiOC/C_free nanocomposite with mixed SiC_xO_4−x 0 ≤ x ≤ 4 units, whereas the CO₂-pyrolyzed sample (SiOC–CO₂) is a SiO₂/C_free nanocomposite with exclusively SiO₄ units forming the amorphous network. Therefore, in this study we investigate two model systems, addressing the question as to whether the mixed SiC_xO_4−x units in the SiOC glass play an essential role regarding electrochemical performance. The UV-Raman analysis reveals that the sp² carbon present in the mixed bond-containing sample is more disordered/has more defects than the one dispersed in the SiO₂ matrix. Apart from the above dissimilarities, the materials present comparable microstructures and a similar amount of free carbon. Nevertheless, SiOC–Ar recovers almost twice higher reversible Li-ion storage capacity than SiOC–CO₂ (325 vs. 165 mA h g⁻¹, respectively). We rationalize this difference in terms of the enhanced Li-ion storage in the more disorder free carbon phase of SiOC–Ar, while this disorder is induced by the presence of the mixed-bond units.

Ceramics are highly chemically, thermally, and mechanically resistant. These remarkable propertiers make them useful across multiple industries; but also, difficult to mold into complex shapes. A possibility to make convoluted ceramic parts is to use preceramic polymers (PCPs) in liquid form. The PCP resin is first solidified in a desired geometry and then transformed into ceramic compounds through a pyrolysis step that preserves the shape. Light‐based additive manufacturing (AM) is a promising route to achieve solidification of the PCP resin. Different approaches, such as stereolithography, have already been proposed but they all rely on a layer‐by‐layer printing process which limits printing speed and object geometry. Herein, the fabrication of complex 3D centimeter‐scale ceramic parts by using tomographic volumetric printing is presented, which is fast and offers a high‐resolution and geometrical design freedom. First, a photosensitive polysiloxane preceramic resin that is solidified by projecting light patterns from multiple angles is formulated. Then, the obtained 3D printed parts are converted into ceramics by pyrolysis. The strength of this approach is demonstrated through the fabrication of smooth, dense microcomponents exhibiting overhangs and hollow geometries without the need of supporting structures. Their resistance to thermal stress and harsh chemical treatments is characterized.