IntroductionPorous silicon-based anode materials with their high theoretical specific capacity (i.e., approximately 4200 mA·h·g⁻¹) and unique porous structure have a promising application potential in the field of lithium-ion batteries. Their porous structure provides effective buffering space for the significant volume change (i.e., 300%) of silicon during charging and discharging, effectively mitigating material pulverization and maintaining the integrity of the electrode structure, thereby enhancing battery cycle stability and Coulombic efficiency, and greatly increases the utilization rate and conductivity of active materials, thus enhancing the energy density of lithium-ion batteries. However, despite the enormous application prospects of porous silicon-based anode materials, their high preparation costs, low initial Coulombic efficiency, and capacity fade after long-term cycling remain some critical factors restricting their commercialization.To address these issues, recent studies mainly focus on nanostructure design, composite material development, electrolyte optimization, and large-scale preparation techniques. The emergence of silicon-carbon composite materials, which embed silicon nanoparticles into a porous carbon matrix, can construct a good conductive network, effectively improving material conductivity, and further enhance the buffering capacity for silicon volume changes, significantly improving battery cycle stability and rate performance. In this paper, a porous silicon-carbon layered silicon-based composite was prepared as an anode material. In addition, the electrochemical performance of this material was also investigated.MethodIn the preparation process, silicon nanopowder was first uniformly dispersed with a mixed solvent of deionized water and anhydrous ethanol, and then sonicated under ultrasound to ensure uniform dispersion of silicon nanopowder. Subsequently, PVP (polyvinylpyrrolidone) and glucose/sucrose were added to the dispersed suspension as a pore-forming agent and two carbon sources, and stirred at room temperature to form a uniform precursor sol. The two precursor sols, i.e., Si/PVP/glucose and Si/PVP/sucrose, were placed into the ink cartridges of a microelectronic printer, and the gels were uniformly printed onto copper foil by a 3D printing technology. Finally, the carbon-containing substances in the electrode were completely reduced to amorphous carbon after vacuum drying and carbonization treatment. Note that different carbon sources (i.e., glucose and sucrose) released different amounts of gas during the carbonization process, leading to subtle changes in the electrode structure and subsequently affecting its electrochemical performance.The prepared electrode materials were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and other characterization techniques.Results and discussionThe results show that larger pores with a uniform pore distribution exist in Si@PVP/glucose structure, and the electrode exhibits minimal cracking after charging and discharging cycles, demonstrating the superior mechanical stability and resistance to expansive internal stresses. In contrast, the pore distribution of Si@PVP/sucrose is relatively uneven, and the electrode exhibits greater cracking after cycling, leading to a decrease in cycle stability and electrochemical performance. These results demonstrate that the Si@PVP/glucose structure electrode exhibits a greater ability to withstand expansive internal stresses and has a higher cycle retention rate. The electrochemical performance tests further validate the superiority of the Si@PVP/glucose composite material. After 100 cycles of charging and discharging, the specific capacity of the Si@PVP/glucose electrode reaches 1095 mA·h·g⁻¹, with a reversible capacity retention rate of 97.4%, while the specific capacity of the Si@PVP/sucrose electrode is only 970 mA·h·g⁻¹, with a reversible capacity retention rate of 91.0%. It is indicated that the Si@PVP/glucose composite material has significant advantages in optimizing the performance of porous silicon-based anode materials, particularly in improving cycle stability and rate performance.ConclusionsThis study prepared a porous silicon-carbon layered silicon-based composite (i.e., Si@PVP/glucose) as an anode material, and the performance was optimized. The results showed that the Si@PVP/glucose electrode material exhibited a greater ability to withstand expansive internal stresses and had a higher cycle retention rate. The electrochemical performance tests further validated the superiority of the Si@PVP/glucose material.It is indicated that this porous silicon-based anode material could have a promising application potential in the field of energy storage and conversion for high-energy-density and long-life batteries.