An Easy Method of Synthesis Co(x)O(y)@C Composite with Enhanced Microwave Absorption Performance

Design of interface-controllable magnetic composite towards the wideband microwave absorber is greatly significance, however, it still remains challenging. Herein, we designed a spherical-like hybrids, using the Co(3)O(4) and amorphous carbon as the core and shell, respectively. Then, the existed Co(3)O(4) core could be totally reduced by the carbon shell, thus in Co(x)O(y) core (composed by Co and Co(3)O(4)). Of particular note, the ratios of Co and Co(3)O(4) can be linearly tuned, suggesting the controlled interfaces, which greatly influences the interface loss behavior and electromagnetic absorption performance. The results revealed that the minimum reflection loss value (RL(min)) of −39.4 dB could be achieved for the optimal Co(x)O(y)@C sample under a thin thickness of 1.4 mm. More importantly, the frequency region with RL < −10 dB was estimated to be 4.3 GHz, ranging from 13.7 to 18.0 GHz. The superior wideband microwave absorption performance was primarily attributed to the multiple interfacial polarization and matched impedance matching ability.