## 2 SiOC-Based Anode Materials
Their study suggests that the high capacity of the SiOC anode may be related to the complex amorphous silicon-oxy-carbon structure, in which the silicon atoms share bonds with both oxygen and carbon atoms. Possible reversible lithium storage locations include hybrid Si-O-C tetrahedra forming an amorphous network, micropores of the glass phase, and free carbon clusters. In order to achieve high capacity retention in SiOC materials, [PERSON] et al. [19] proposed a cost-effective synthetic route in which silicon-based composites are encapsulated from highly porous silicon (obtained through silicate reduction) in an organic carbon and polymer-derived silicon-oxycarbon (C/SiOC) matrix. This method yields silicon-based anode materials with a capacity of 2000 to 3000 mAh\(\cdot\)g\({}^{-1}\), a coulombic efficiency of over 99.5%, and nearly 100% capacity retention over more than 100 cycles. Molecular dynamics simulations revealed that the highly porous silicon morphology provides a strained free volume, thus preventing macroscopic changes during the initial Li-Si alloying process. The carbon layer ensures electrical contact, while the SiOC matrix significantly reduces the interface between the electrolyte and the electrode material, thereby inhibiting the formation of a solid electrolyte interphase on the silicon. Different atmospheres will influence the structure of SiOC. [PERSON] et al. [32] compared two SiOC glasses synthesized by pyrolysis in different atmospheres, one in argon and the other in carbon dioxide. The argon pyrolysis of SiOC (SiOC-Ar) exhibits a higher reversible lithium-ion storage capacity (325 mAh\(\cdot\)g\({}^{-1}\)), while the CO\({}_{2}\) pyrolysis of SiOC (SiOC-CO\({}_{2}\)) is 165 mAh\(\cdot\)g\({}^{-1}\). NMR and spectroscopy analysis showed that the atmosphere affected the material structure, CO\({}_{2}\) led to the conversion of SiOC to silica network, and there may be more activated carbon in the Ar atmosphere. UV-Raman revealed that there were more defective carbon phases in Ar-treated aerogels, and more ordered carbon phases in CO\({}_{2}\)-treated aerogels, which affected the lithium-ion storage capacity. Therefore, it can be seen that the more disordered carbon phase in SiOC-Ar is conducive to lithium-ion storage, and this disorder is caused by the hybrid bonding unit. Although SiOC anodes have many advantages relative to graphite and silicon, the practical application of SiOC as an anode material is hindered by its inherent characteristics. Its capacity has currently reached a bottleneck and requires further improvement, while issues such as poor conductivity and low initial coulombic efficiency need to be addressed. By combining SiOC with other materials, such as high-capacity tin or silicon nanoparticles [33], carbon nanotubes [34], graphene [24; 35], and reduced graphene oxide, and designing its structure to leverage the advantages of each, multiple challenges can be solved simultaneously. For example, [PERSON] et al. [36] investigated SiOC/Sn nanocomposites, where disordered carbon serves as an effective charge carrier and an active site for lithium-ion insertion, thereby enhancing electrochemical performance. The SiOC/Sn nanocomposites were synthesized using functional PEOS siloxanes. This approach helps prevent particle crushing and cracking at the rough solid/electrolyte interface, promoting a uniform distribution of metal nanoparticles within the PDCs matrix through carbon-thermal reduction. By inhibiting the aggregation of Sn in the SiOC matrix, a uniform lithium-ion diffusion path is maintained, which enhances both electrochemical performance and cycle life. Additionally, the high-rate performance of SiOC/Sn nanocomposites facilitates fast lithium-ion diffusion kinetics and efficient electron transport. The specific capacities of these nanocomposites range from 200 to 1300 mAh\(\cdot\)g\({}^{-1}\) and improve cycling stability and lithium-ion diffusion efficiency by Li\({}_{22}\)Sn\({}_{5}\) reversible formation of alloys during lithiation/delithiation.