Hierarchical sandwich NiFe layered double hydroxide/reduced graphene oxide for high energy density asymmetric supercapacitors

Abstract

• A hierarchical sandwich-type NiFe layered double hydroxide/reduced graphene Oxide (NiFe-LDHs/rGO) composite electrode materials have been designed and synthesized via a facile impregnation method. • The NiFe-LDHs/rGO composite electrode can achieve a high specific capacitance of 1319 F g -1 at 1 A g -1 and show good cycling performance over 1000 cycles. • The asymmetric supercapacitor based on NiFe-LDHs/rGO as a positive electrode and N-doped hollow carbon sphere as a negative electrode was assembled and exhibited a high energy density as well as good cycling stability. Rational design and fabrication of composite electrode materials with high energy storage performance of supercapacitors is of great importance from both theoretical and practical viewpoints. Herein, a hierarchical sandwich-type NiFe layered double hydroxide/reduced graphene Oxide (NiFe-LDHs/rGO) composite electrode materials were successfully synthesized through a one-step hydrothermal method. It is found that the prepared NiFe-LDHs/rGO composite electrode can achieve a high specific capacitance of 1319F g −1 at 1 A g −1 and show good cycling performance with a retention rate of 80% over 1000 cycles. Furthermore, the asymmetric supercapacitor based on NiFe-LDHs/rGO as a positive electrode and N -doped hollow carbon sphere as a negative electrode was assembled and exhibited a high energy density of 37 Wh kg −1 at a power density of 423 W kg −1 as well as good cycling stability. The exceptional electrochemical performance of the NiFe-LDHs/rGO composite indicates its potential application in high-performance supercapacitors.