Metal ion-assisted conversion of Co-ZIF-L to CoNi-layered double hydroxides with high electrochemical properties for supercapacitors

Metal ion-induced etching can effectively convert zeolitic imidazolate frameworks (ZIFs) to CoNi-layered double hydroxides (LDH). Here, different metal-ion-assisted etching methods are utilized to convert Co-ZIF-L to CoNi-LDH with various morphologies and electrochemical properties. The resultant CoNi-LDH (CoNi-1) with a composition of Co0.7Ni0.3(OH)2 displayed a high electrochemical performance when Co-ZIF-L was treated in N, N-dimethylformamide-ethanol solution containing Co2+ ions followed by Ni2+ ion-induced etching under hydrothermal condition. The improved electrochemical performance of CoNi-1 can be attributed to structural advantages, where the well-dispersed ultrathin CoNi-LDH layers favor the exposure of surface active sites and promote ion diffusion to maximize electrochemical properties.