Self-propagating Combustion Synthesis and Sodium Storage Performance of Manganese-rich P2/P3 Biphasic Na 0.67 Mn 0.9 Ni 0.1 O 2

The P2-type manganese-rich layered oxides have emerged as highly promising cathode materials for sodium-ion batteries owing to their exceptional advantages including high specific capacity and low cost. However, huge challenges remain for their practical applications, particularly the capacity degradation under deep desodiation conditions and the structural sensitivity to calcination temperatures during material synthesis. In this study, we successfully fabricated a P2/P3 biphasic Na 0.67 Mn 0.9 Ni 0.1 O 2 (designated as NMNO-800) cathode material through a carefully controlled self-propagating combustion synthesis method with precise temperature regulation. Comprehensive X-ray diffraction characterization revealed that the calcination temperature plays a critical role in phase formation. NMNO-700 (calcined at 700 ℃) exhibited a pure P3-phase structure with R 3 m space group, while NMNO-900 (calcined at 900 ℃) showed a pure P2-phase structure with P 63/ mmc space group. Remarkably, the NMNO-800 sample calcined at the optimal temperature of 800 ℃ demonstrated a well-defined and stable P2/P3 biphasic structure, with the phase ratio quantitatively determined to be 42.4% P2-phase and 57.6% P3-phase through Rietveld refinement analysis. Scanning electron microscope (SEM) observations further confirmed that the NMNO-800 possesses a unique hierarchical nano-micro composite architecture, consisting of well-dispersed micron-sized particles ranging from 1.94 to 2.57 μm in diameter, with numerous nanoparticles distributed on the surface of these micron-scale sheet-like particles. This ingenious designed biphasic Na 0.67 Mn 0.9 Ni 0.1 O 2 successfully combines the advantageous features of both P2 and P3 phases, maintaining the excellent structural stability characteristic of P2-phase while preserving the high initial capacity inherent to P3-phase, thereby achieving superior electrochemical performance. Specifically, the NMNO-800 delivers an outstanding reversible capacity of 165.44 mAh/g at 0.2 C rate, maintains a respectable capacity of 89.18 mAh/g even at an extremely high rate of 10 C, and shows excellent cycling stability with 84.2% capacity retention after 100 cycles at 0.5 C rate, significantly outperforming all single-phase counterparts. All the results indicate that the P2/P3 biphasic structure enhances the rate performance of manganese-rich layered oxide cathode materials, improves sodium ion diffusion efficiency, and maintains good cycling stability. Key words: sodium ion battery, cathode materials, layered oxides, P2/P3 biphase, Mn-rich materials Cite this article Qingtang Zhang, Chunyang Du, Pengfei Gao, Xiaomei Wang. Self-propagating Combustion Synthesis and Sodium Storage Performance of Manganese-rich P2/P3 Biphasic Na 0.67 Mn 0.9 Ni 0.1 O 2 [J]. Acta Chimica Sinica , 2026, 84(1): 64-72. Export EndNote | Reference Manager | ProCite | BibTeX | RefWorks share this article ( )