Phase regulation for electrochemical rapid reconstructed ZIFs-derived hierarchical multiphase NiCoMn-Se for supercapacitors with high energy density and stability

Transition metal selenides (TMSes) have significant advantages in energy storage materials, and stimulating the material activity to enhance the performance of electrodes can realize hybrid supercapacitors (HSCs) with high practical value. Herein, the rapid reconstruction of ZIFs (zeolite-imidazole-frameworks) with the assistance of electrochemical methods is guided directionally to generate active materials and construct stable hollow layered NiCoMn-LDH@CNFs (carbon-nitrogen frameworks). The multiphase selenides (NiCoMn-Se@CNFs) with abundant phase valence after controlled selenization enhance the redox reaction activity, and the electrodes with high energy density and stability are successfully prepared. After systematically studying the influence of time selenization and metal content, proportion, and phase regulation, the capacity of the optimal electrode NiCoMnSe@CNFs can reach 487.5 mAh g-1 at 1 A g-1 (3510.0 F g-1). The assembling HSC (NiCoMn-Se//activated carbon) shows excellent energy density (90.8 Wh kg-1 at 0.8 kW kg-1) and ultra-high stability (103.0 %, 20,000 cycles), which proved the high efficiency/rationality of the electrode design.