High-performance supercapacitor based on three-dimensional flower-shaped Li4Ti5O12-graphene hybrid and pine needles derived honeycomb carbon

Abstract

A three-dimensional (3D) flower-shaped Li₄Ti₅O₁₂-graphene (Gr) hybrid micro/nanostructures and pine needles derived carbon nanopores (PNDCN) has been prepared by using the effective hydrothermal process. Due to the unique micro/nanostructures which can provide abundant surface active sites, the obtained 3D Li₄Ti₅O₁₂-Gr displays a high specific capacitance of 706.52 F g^-1 at 1 A g^-1. The prepared PNDCN also exhibits high specific capacitance of 314.50 F g^-1 at 1 A g^-1 benefiting from its interconnected honeycomb-like hierarchical and open structure, which facilitates the diffusion and reaction of electrolyte ions and enables an isotropic charging/discharging process. An asymmetric supercapacitor utilizing Li₄Ti₅O₁₂-Gr as positive electrode and PNDCN as negative electrode has been fabricated, it delivers a high energy density of 35.06 Wh kg^-1 at power density of 800.08 W kg^-1 and outstanding cycling stability with 90.18% capacitance retention after 2000 cycles. The fabrication process presented in this work is facile, cost-effective, and environmentally benign, offering a feasible solution for manufacturing next-generation high-performance energy storage devices.

Keywords: Asymmetric supercapacitor; Carbon nanopores; Flower-shaped Li(4)Ti(5)O(12)-graphene hybrid; High performance; Hydrothermal process.