Induction of lattice distortion and interface modulation in Co2NiO4@RGO nanosheets by fluorine for boosting electrochemical energy storage properties

F-CN@RGO presents multi-dimensional synergy between the conductive framework and heteroatom doping. • F-doping induces lattice distortion, optimizes the electronic structure, enhances redox kinetics. • It exhibits outstanding long-cycle stability, with a capacitance retention of 86.8% after 30,000 cycles. • The asymmetric supercapacitor achieves a high energy density of 87.75 Wh·kg −1 and excellent cycling stability. Supercapacitors possess exceptional capacity to transfer energy quickly, but increasing cycle stability and energy density is still a major problem that hinders their commercial applications. This study uses a one-step hydrothermal method to build and construct a fluorine F-doped three-dimensional (3D) Co 2 NiO 4 @reduced graphene oxide (RGO) heterostructure (referred as F-CN@RGO) on the nickel foam (NF) electrical collector. RGO-wrapped NF functions as 3D conductive framework that suppresses the volume strain during long-term cycling while simultaneously improving the electron transfer efficiency, electrical conductivity, and specific surface area. F-doping regulates the electronic structure, surface properties, and chemical stability of Co 2 NiO 4 @RGO. The high electronegativity of F ions accelerates the electron transfer, induces the lattice distortion of Co 2 NiO 4 @RGO, and consequently modulates its electronic structure and interfacial reaction kinetics. Electrochemical tests show that the activated F-CN@RGO (A-F-CN@RGO) has a high specific capacitance of 8.76 F·cm −2 (5 mA·cm −2 ). After 30,000 cycles, the asymmetric supercapacitor with A-F-CN@RGO and activated carbon as the electrodes retains 88.2% of its initial capacitance. By generating multi-dimensional synergistic effects with rational design structure between the substrate and active materials as well as heteroatoms and host materials, this work offers a universal technique for the controlled production of high-performance electrodes for supercapacitors. Download: Download high-res image (403KB) Download: Download full-size image