## 4 Other Si-Based Anode Materials  
In addition to the widely studied SiOC and SiCN, researchers have also conducted some exploratory work on the application of polymer precursor ceramics such as SiBCN and SiBCN in the anode of lithium-ion batteries. SiBCN, polymer-derived quaternary silicon boron explonitride (SiBCN) ceramics offer several advantages, including high strength, low density, excellent high-temperature stability, and strong resistance to oxidation and creep [54]. These properties make them ideal materials for high-temperature applications, such as fibers, bulk ceramics, composites, and membranes. Recently, SiBCN-based ceramics have attracted growing interest as anode materials for lithium-ion batteries. For instance, [PERSON] et al. investigated the electrochemical performance of SiBCN composites modified with carbon units (e.g., carbon nanotubes, graphene oxide) as anode materials for lithium batteries [17; 18]. The results revealed that pure SiBCN ceramics exhibited a low discharge capacity of less than 101 mAh\(\cdot\)g\({}^{-1}\), but the incorporation of carbon units significantly enhanced their electrochemical performance [54]. Studies on the solid-state mixing of MWCNT with SiCN ceramic particles have also yielded promising results. These composites demonstrated a 14% improvement over SiCN, with a reversible capacity of approximately 750 mAh\(\cdot\)g\({}^{-1}\) in the first cycle and 400 mAh\(\cdot\)g\({}^{-1}\) after the 30 th cycle [55]. A recent study has shown that Si(B)CN-based anodes outperform SiCN anodes in both effective capacity and cycle life. As illustrated in Figure 9, the reversible capacity of polysilazane-based SiCN increased fourfold when doped with boron and CNT. [PERSON] et al. [56] studied the effect of nitrogen-sulfur co-doped graphene (NSGs) sheets on the electrochemical performance of SiBCN ceramics as an anode material for lithium-ion batteries. The nanocomposite exhibited a reversible capacity of 785 mAh\(\cdot\)g\({}^{-1}\) at a current density of 450 mA g\({}^{-1}\) over 800 cycles, with an average capacity decay of 0.006% per cycle. Its high cycling stability can be attributed to the stacked graphene sheets of NSGs and the increase in disordered carbon, such as the rearrangement of \(-\)sp\({}^{2}\) carbon chains and the formation of B(C)N domains in the PDCs. In order to improve the performance of SiBCN, [PERSON] et al. [57] inserted GN sheets into the ceramic network of polymer-derived SiBCN through liquid dispersion (SiBCN/GN-ld) and solid phase blending (SiBCN/GN-sp) at 1100 \({}^{\circ}\)C. Electrochemical measurements revealed that the SiBCN/GN-ld exhibited an impressive first-cycle discharge capacity of 844.2 mAh g\({}^{-1}\) at a current density of 80 mA g\({}^{-1}\), surpassing the performance of SiBCN/GN-sp, SiBCN, and GN anodes. The discharge capacity decreased to 347 mAh g\({}^{-1}\) and remained stable in this range over 30 cycles. It shows that the GN layers played a crucial role in stabilizing the SiBCN matrix and mitigating the expansion of the material structure during charge-discharge cycles. The relevance between the electrochemical capacities of the SiBCN/GN composites and their compositions and structures suggest broad prospects to improve the electrochemical performance of these materials through molecular design and/or structural control. Figure 9: (**a**) Cycling performance of SiCN, Si(B)CN, and Si(B)CN-CNT composite anodes. (**b**) The best performance, characterized by the minimal loss in the first cycle and the highest charge capacity, was achieved by the specimen synthesized at approximately 1100 \({}^{\circ}\)C. Copied with permission from American Chemical Society [23]. Doping with heteroatoms (such as boron or nitrogen) through pyrolysis of heteroatom-containing precursors [19; 20] and fabricating composites with other materials like carbon-based substances (e.g., CNTs, graphene), metals and metal compounds have also been explored to enhance the electrochemical properties of SiOC materials.