Heterostructured starfish-like C/CoNiO2 has been prepared by a solvothermal synthesis and was further thermally etched. Owing to the localized electron polarization and significant magnetic loss, C/CoNiO2 heterostructures with starfish-like morphology exhibited significantly enhanced electromagnetic attenuation and reflection loss. Such singularities enable this lightweight C/CoNiO2 to become an outstanding microwave absorber with wide bandwidth and strong absorption. These findings provide new insight into the possible mechanism of microwave absorption due to electron polarization and demonstrates that it is critical to improve microwave absorption performance for future applications.