Ionic liquid assisted construction of synergistic modulated multiphase hybrid composites for boosting electrochemical energy storage.

The unique structure and strong interaction of multiphase hybrid materials have garnered significant attention as prospective candidates for electrode materials in the realm of energy storage. The present study presents a rational design of a functional NiSe-CoSe/N, B double-doped carbon hybrid composite (NCS/C), resulting in the emergence of various novel cooperative regulatory mechanisms involving: (i) the heterogeneous structure of NiSe and CoSe generates built-in electric fields to increase electron mobility; (ii) the incorporation of polyatomic double-doped carbon (N, and B) expedites electron transfer rate; intriguingly, (iii) ionic liquids not only serve as polyatomic dopants in the reaction system but also influence the microstructure of the composite. Benefiting from these synergistic effects, the NCS/C hybrid exhibits remarkable charge storage capacity and rapid electrochemical kinetics, driven by its multi-fold hollow structure and multicomponent cooperative modulation. The capacity (682 C g at 1 A g) and rate performance of NCS/C surpass those of other monometallic selenides (NiSe/N, B co-doped carbon (NS/C) and CoSe/N, B co-doped carbon (CS/C)) within the same system. In the meantime, an asymmetric device using NCS/C as the cathode material performs admirably, displaying an exceptional energy density (51.3 Wh kg at 1.28 kW kg). The present research provides valuable perspectives for the innovative design and fabrication of advanced electrode materials exhibiting exceptional electrochemical properties. We firmly believe that hollow structures featuring multiple cooperative regulatory mechanisms and abundant folds will garner significant attention.