Embedding MnO@Mn 3 O 4 Nanoparticles in an N‐Doped‐Carbon Framework Derived from Mn‐Organic Clusters for Efficient Lithium Storage

The first synthesis of MnO@Mn 3 O 4 nanoparticles embedded in an N‐doped porous carbon framework (MnO@Mn 3 O 4 /NPCF) through pyrolysis of mixed‐valent Mn 8 clusters is reported. The unique features of MnO@Mn 3 O 4 /NPCF are derived from the distinct interfacial structure of the Mn 8 clusters, implying a new methodological strategy for hybrids. The characteristics of MnO@Mn 3 O 4 are determined by conducting high angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and electron energy loss spectroscopy (EELS) valence‐state analyses. Due to the combined advantages of MnO@Mn 3 O 4 , the uniform distribution, and the NPCF, MnO@Mn 3 O 4 /NPCF displays unprecedented lithium‐storage performance (1500 mA h g −1 at 0.2 A g −1 over 270 cycles). Quantitative analysis reveals that capacitance and diffusion mechanisms account for Li + storage, wherein the former dominates. First‐principles calculations highlight the strong affiliation of MnO@Mn 3 O 4 and the NPCF, which favor structural stability. Meanwhile, defects of the NPCF decrease the diffusion energy barrier, thus enhancing the Li + pseudocapacitive process, reversible capacity, and long cycling performance. This work presents a new methodology to construct composites for energy storage and conversion.