<p>The silicon-carbon composite is the most prominent high-performance anode material for lithium-ion batteries. Carbon is key to improving the large volume expansion and poor cycling performance of silicon-carbon composites. In this study, the nano-silicon/polythiophene composite (Si@PTh) was synthesized via in-situ polymerization and was then calcined to prepare nano-silicon/polythiophene-derived high-sulfur hard carbon (Si@PSHC). In the Si@PSHC, nano-silicon particles are embedded in the high-sulfur hard carbon, which effectively alleviates the volume changes of nano-silicon particles during the lithiation and delithiation processes and facilitates diffusion of lithium ions. Si@PSHC exhibits superior performance as an anode for lithium-ion batteries. Si@PSHC delivers an initial specific charge capacity of 845.30 mAh g^− 1 at 0.1&#xa0;A g^− 1, maintaining a specific charge capacity of 674.40 mAh g^− 1 after 150 cycles at 0.2&#xa0;A g^− 1, and exhibiting a specific charge capacity of 372.94 mAh g^− 1 at a high current density of 3.2&#xa0;A g^− 1.</p> Graphical Abstract <p></p>