P2-type Na2/3Co0.25Mn0.705Si0.045O2 (Si-NCM) high-rate cathode was designed by using silicon of the nonmetallic element as dopant and developed by the simple solid-state route for sodium-ion batteries. XRD refinements confirm the P2-type hexagonal structure with space group (SG: P6(3)/mmc), in which Si4+ ions substitute the Mn site of P2-Na2/3Co0.25Mn0.75O2 (NCM) lattice without any impurity phases of Si-related substances. Si-NCM delivers the initial capacity of 144mAhg(-1) at 0.1C with the capacity retention of 80.1% after 100 cycles, and the discharge capacity of 120mAhg(-1) at 1C with 83.4% retention at 200th cycle. Particularly, excellent capacity retentions of 90.2% after 260 cycles and 85.8% after 500 cycles at 5C have been achieved. Si-doping can expedite the superior cycle stability of Si-NCM compared to NCM, which is attributed to the more powerful Si-O, T-M-O and O-O bonds, more stable occupancy rate in the Na-e site of unit cell and particularly ascribed to the reversible two-phase transition of P2-P3-P2 in the process of Na+ extraction and intercalation. Hence, SiO2 as dopant is a novel strategy with regard to the development of high-rate cathode materials for SIBs.