Silicon (Si) nanomaterials attract tremendous attentions when applied as anodes for lithium ion batteries (LIBs) owing to their high capacity, however, they usually suffer from low electronic conductivity and large volume expansion during the charge/discharge processes, resulting in the poor cycling stabilities. In this study, horsetails (HTs) are explored as low cost and renewable resources for deriving Si materials for Li-ion half/full cells for the first time. Moreover, Si@N-doped carbon nanocomposites are fabricated by polypyrrole (PPy) coating and pyrolysis carbonization of PPy at 400 °C for 2 h in Ar atmosphere, and they show enhanced long cycle stabilities for Li-ion half cells (1047.1 mAh g−1 at 0.5 A g−1 after 450 cycles, and 750 mAh g−1 at 1 A g−1 after 760 cycles). Furthermore, the Si@N-doped carbon//LiCoO2 Li-ion full cells are assembled successfully, which display high discharge capacity (705 mAh g−1 at 0.5 A g−1 after 100 cycles). The high performance of Si@N-doped carbon nanocomposite could be attributed to the synergistic effect of high capacity of nanoscale sized Si and long cycle stability of N-doped carbon. It is believed the HTs-derived Si@N-doped carbon nanocomposite has great prospects for practical applications due to low cost and sufficient source of HTs.