Snowflake-like MnO 2 @NiCo 2 O 4 composites were successfully fabricated by employingc rossed snowflake-like MnO 2 nanorodsa sc ores and one-dimensional (1D) NiCo 2 O 4 nanoneedles as shells.I mpressively, the MnO 2 @NiCo 2 O 4 compositese xhibited ah ighly efficient electromagnetic wave (EMW) absorbing capability,a nd the minimum reflection loss (RL) value reached À58.4 dB at 6.8 GHz forathickness of 4.0 mm. The reasons for the improvedE MW absorption capabilityo fs nowflake-like MnO 2 @NiCo 2 O 4 compositesw ere analyzed. The unique core-shell structure, good impedance matching, and high dielectricl oss were all found to be important contributors. Moreover,t he interfacial polarization mainly stemmedf rom the heterostructure, am icrocurrent generated from the 1D MnO 2 nanorods and NiCo 2 O 4 nanoneedles under alternating electromagnetic fields, and the synergistic effect from the differentc omponents werea ll beneficial to improve the EMW absorption performance. These results demonstrated that snowflake-like MnO 2 @NiCo 2 O 4 composites could be utilizeda sp romising materials for practical EMW absorbinga pplications.[a] S.