Epitaxial ZnCoS nanodendritics grown along 3-D carbonaceous scaffolds for high-performance hybrid supercapacitors

• ZnCoS/Cs are synthesized via the in-situ epitaxial growth of ZnCoS nanodendritics along 3-D carbonaceous scaffolds. • The synthesis procedure of 3-D glucose-derived carbonaceous scaffolds is absolutely " green". • ZnCoS/C 20 displays a maximum specific capacity of ~682 C/g at 1 A/gwith good rate capability and cycling stability. • Thehybrid supercapacitor exhibits an energy density of 40.6 W h kg −1 at a power density of 762 W kg −1 . Zn-Co sulfides with high energy density are promising materials for positive electrodes of supercapacitors. However, it is still imperative to develop a favorable architecture of Zn-Co sulfides to obtain a satisfying electrochemical response with improved electrons and ions transfer efficiency. Herein, for the first time, ZnCoS/C with the specific structure, numerous nanodendritics ZnCoS epitaxial growth along 3-D glucose-derived carbonaceous (C) scaffolds, is highlighted. The possible growth process and formation mechanism are carefully investigated. The functions of functional groups covalently bonding to C frameworks and deriving from PVP molecules are discussed to offer insights to guide the rational design of active and selective materials for electrochemical supercapacitors. We evaluate the electrochemical response of obtained ZnCoS/Cs. By varying the content of C of the reaction solutions, ZnCoS/C 20 synthesized with the addition of 20 mg C displays a maximum specific capacity of 682 C/g at 1 A/g, which is approximately 2 times greater than the bare ZnCoS electrode. The electrode ZnCoS/C 20 delivers outstanding rate capability (86% after increasing the current density 20 times) and reserves 89% of its initial specific capacity after 7000 charging/discharging cycles at 20 A/g. A hybrid supercapacitor was fabricated with ZnCoS/C 20 positive electrode and PrGO (porous reduced graphene oxide) negative electrode. The assembled supercapacitor displays an energy density of 40.6 W h kg −1 at a power density of 762 W kg −1 and a remarkable cycling performance of 72% after 6000 cycles. This work provides a promising strategy for the fabrication of metal sulfides-based hybrids for high-performance supercapacitors.