Bimetallic ZnNi-ZIF/LDH@P composite electrode derived from zif-8 for efficient asymmetric supercapacitor with outstanding capacitive and stability

The application of zeolite imidazole salt metal organic frameworks (ZIFs) and layered double hydroxides (LDHs) as bimetallic materials for supercapacitor electrodes is extensive, however, their inherent limitations hinder broader usage in supercapacitors. In this work, we developed a ZnNi-ZIF/LDH composite with a honeycomb structure through a sequential process involving ion doping and hydrolysis, utilizing ZIF-8 as a template to achieve a nanoscale honeycomb architecture. Subsequent phosphorization treatment yielded ZnNi-ZIF/LDH@P composite, further improving its conductivity. This process significantly enhanced the capacitive performance and stability of the composite electrode. The ZnNi-ZIF/LDH@P composite electrode revealed an excellent specific capacitance of 2855 F·g −1 at a current density of 2 A·g −1 , maintaining an impressive 93.4 % capacitance retention after 6000 charge-discharge cycles at a current density of 15 A·g −1 . The assembled ZnNi-ZIF/LDH@P//AC asymmetric supercapacitor was capable of powering a HENU light panel for at least 2 min, and its specific capacitance remained 96.4 % of the initial value after 4000 cycles at a current density of 5 A·g −1 . Overall, the ZnNi-ZIF/LDH@P composite demonstrates outstanding capacitance performance, highlighting its great potential in the field of energy storage.