Design and characterization of monolayer Ti3C2 MXene/NiCo2O4 nanocones hybrid architecture for asymmetric supercapacitors

• NiCo 2 O 4 was hydrothermal grown on the manolayer Ti 3 C 2 nanosheets. • The s-Ti 3 C 2 /NiCo 2 O 4 hybrid architecture presents the outstanding electrochemical performances. • The fabricated asymmetric device based on s-Ti 3 C 2 /NiCo 2 O 4 delivered an enhanced energy density under a broad voltage window. The 2D Ti 3 C 2 T x MXene are promising supercapacitor electrode materials due to their considerable high conductivity, surface functional groups, and redox reactions, however, also subjected to compact restack of multi-layered structure. In this study, monolayer Ti 3 C 2 T x modified by NiCo 2 O 4 nanocones (s-Ti 3 C 2 /NiCo 2 O 4 ) with large specific surface area (158.8 m 2 ∙g −1 ) were designed and obtained by a facile method. Then an asymmetric device was assembled based on positive s-Ti 3 C 2 /NiCo 2 O 4 electrode and negative active carbon electrode for the first time. Then, a widened voltage window of 1.6 V for asymmetric device is realized, which is almost twice wider than that of the common symmetric device. The device deliveries a maximum specific capacitance of 73.8F∙g −1 at 1A∙g −1 with a good stability. More importantly, the energy density of device also is significantly enhanced to 94.46 Wh∙kg −1 at a power density of 2882.0 W∙kg −1 , supporting a substantial promise for energy storage applications.