In this work, we study the impact of the preceramic precursor vinyltriethoxysilane (VTES) on the electrochemical performance of silicon oxycarbide (SiOC) glass/graphite composites. We apply an innovative approach based on high-power ultrasounds in order to obtain highly homogenous composites with a uniform distribution of small graphitic flakes. This procedure enhances gelation and drying of VTES-based preceramic polymer/graphite blends. The SiOC/graphite composites reveal stable capacities (up to 520 mAh g⁻¹ after 270 cycles), which are much higher than the sum derived from the ratio of the components. Additionally, the first cycle Coulombic efficiencies obtained for the composites are 15% higher than that of the pristine VTES-based SiOC ceramic. These properties are identified as the synergistic effect, originated from the addition of graphite to VTES-based SiOCs. Interestingly, such improvement in electrochemical performance is not noticed in the case of analogous SiOC/graphite composites based on phenyltriethoxysilane (PhTES) precursor. The microstructural investigation of the composites based on two different preceramic precursors using solid-state ²⁹Si NMR and Raman Spectroscopy unveils the reason for such discrepancy in their electrochemical behaviour.

在这项工作中，我们研究了陶瓷前驱体乙烯基三乙氧基硅烷 (VTES) 对碳氧化硅 (SiOC) 玻璃/石墨复合材料电化学性能的影响。我们采用基于高功率超声波的创新方法，以获得具有均匀分布的小石墨片的高度均匀的复合材料。该程序增强了基于 VTES 的陶瓷前驱体聚合物/石墨混合物的凝胶化和干燥。SiOC/石墨复合材料显示出稳定的容量（高达 520 mAh g ^-1270 次循环后），这远高于由组分比率得出的总和。此外，复合材料的第一次循环库仑效率比原始 VTES 基 SiOC 陶瓷高 15%。这些特性被确定为协同效应，源于向基于 VTES 的 SiOC 添加石墨。有趣的是，在基于苯基三乙氧基硅烷 (PhTES) 前体的类似 SiOC/石墨复合材料的情况下，没有注意到电化学性能的这种改进。使用固态²⁹ Si NMR 和拉曼光谱对基于两种不同陶瓷前驱体的复合材料进行微观结构研究，揭示了其电化学行为存在差异的原因。