A confined derivative strategy of core–shell SiO₂ coating metal-organic framework structures for supercapacitors

Metal-organic framework (MOF)-derived porous carbon has garnered extensive interest. However, MOFs will shrink inward during carbonization, which will limit the structural diversity and potential for application. In this work, a general synthesis strategy was reported. Various MOF@mSiO₂ core–shell composites were synthesized by in-situ growth, utilizing MOFs as precursors. Further, hollow mesoporous carbon was prepared after calcination by the outward contraction effect induced by compact silica coating. Furthermore, the incorporation of metal heteroatoms can also significantly enhance electrochemical performance due to the synergistic influences of bimetallic atoms. The synthesized Fe-Zn-N-MC-600 MOF-derived carbon material achieved 453 F·g⁻¹ at 0.5 A·g⁻¹ and an outstanding capacity retention rate (97% after 5000 cycles at 5 A·g⁻¹). In addition, the prepared Fe-Zn-N-MC-600//AC asymmetric supercapacitors achieved 375 F·g⁻¹ at 5 A·g⁻¹. Our task opens a universal path for MOF-derived carbon, offering new possibilities in supercapacitor technology.