Rose-like Ni-Co-Mn-S@N-CDs electrode material for flexible hybrid supercapacitors with high electrochemical performance

Ternary transition metal sulfides are extensively considered as supercapacitor electrode materials due to their remarkable electrochemical properties . However, inferior electrical conductivity and structural stability severely limit their applications. Here, we address these limitations by introducing N-doped carbon dots (N-CDs) into Ni-Co-Mn-S nanoflowers via a two-step hydrothermal process followed by electrodeposition . Ni-Co-Mn-S nanoflowers feature a skeleton structure supporting rich ion transfer paths and abundant active sites, while electrodeposited N-CDs increase the electrical conductivity and enhance the cycling performance. The resulting Ni-Co-Mn-S@N-CDs material demonstrates a remarkable specific capacity of 2267 F g −1 at 1 A g −1 and maintains 96.2 % capacity after 10,000 cycles at 10 A g −1 . Moreover, this electrode material allows the development of hybrid supercapacitors with an impressive energy density of 61.6 Wh kg −1 at 800 W kg −1 and a superior capacitance retention of 89.0 % after 20,000 charge/discharge cycles at 5 A g −1 , alongside an excellent flexibility under various deformations. These findings represent a significant advancement in hybrid solid-state supercapacitors with promising implications for flexible energy storage technologies.