摘要：Sodium layered oxides generally suffer from deep-desodiation instability in P2 structure and sluggish kinetics in O3 *** will be great to design P2/O3 biphasic materials that bring the complementary merits of both ***,such exploration is hindered by the ambiguous mechanism of material ***,supported by theoretical simulations and various spectroscopies,we prove that P2/O3 biphasic structures essentially originate from the internal heterogeneity of cationic potential,which can be realized by constraining the temperature-driven ion diffusion during solid-state ***,P2/O3 biphasic Na_(0.7)ni_(0.2)Cu_(0.1)Fe_(0.2)Mn_(0.5)O_(2)-δ with well-designed quaternary composition is successfully obtained,exhibiting much-improved rate capabilities(62 mAh g^(-1)at 2.4 A g^(-1)) and cycling stabilities(84%capacity retention after 500 cycles)than its single-phase ***,synchrotron-based diffraction and X-ray absorption spectroscopy are employed to unravel the underlying sodium-storage mechanism of the P2/O3 biphasic *** work presents new insights toward the rational design of advanced layered cathodes for sodium-ion batteries.