Boosted 2D graphene nanosheets by organic-inorganic hybrid cross-linker for an efficient and stable supercapacitor

Abstract

Using covalent graphene derivatives in energy storage applications is promising. From this view, covalently cross-linked graphene oxide (GO) nanosheets are designed using polyoligomeric silsesquioxanes-propyl-NH 2 (POPN). Then, by incorporating cobalt sulfide nanoparticles into the porous scaffold, a high-value nanocomposite is formed. In a typical three-electrode cell, this nanocomposite declared substantial specific capacity of 454 and 438 Fg -1 using cyclic voltammetry (CV) and charge-discharge (GCD) assessments. The device is assembled via two identical electrodes containing RGO-SiO 3 -NH2-poss-NH2-SiO 3 -RGO/cobalt sulfide (RGO-Si-POPN-Si-RGO/CoS 2 ). Utilizing CV and GCD methods, specific capacitances of 328 and 315 Fg -1 are realized at a sweep rate and current density of 2 mVs −1 and 0.5 Ag -1 , respectively. The device presents desirable energy density of 18.5 Whkg −1 at the power density of 325 Wkg -1 . More impressively, around 97.9% of the specific capacitance is retained after 5000 charge-discharge cycles. The results confirm exceptional capacitive capabilities and super stability of the nanocomposite suitable for practical systems. • The 3D GO nanoscaffold is developed using an organic-inorganic hybrid cross-linker. • The durability of the developed nanocomposite has been improved, mainly due to the introduction of the POPN. • The symmetric supercapacitor exhibits a high specific capacitance of 328 Fg -1 at the scan rate of 2 mVs −1 . • RGO-Si-POPN-Si-RGO/CoS 2 shows a high capacitance retention of 97.9% after 5000 cycles.