Synthesis of ultra-high specific surface area trimetallic NiCoMg-LDH hollow cage via bimetallic ion etching for hybrid supercapacitors

A trimetallic layered double hydroxide (LDH), NiCoMg-LDH, was rationally designed and synthesized in this paper by hydrolytic etching of Ni2+ and Mg2+ using Co-MOF as a conversion template, during which the rhombic dodecahedral structure of Co-MOF was etched to form a hollow cage structure overlaid with nanosheets on the surface. In comparison to the NiCo-LDH prepared by monometallic ion etching, the NiCoMg-LDH prepared in this study has a larger specific surface area and a more stable hollow porous structure, which can provide a large number of active sites for redox reactions as well as ion transport channels. The trimetallic Ni1Co1Mg-LDH has a higher specific capacity of 2141.62 F g−1 (208.21 mAh g−1) at 1 A g−1 current density compared to the NiCo-LDH. It also keeps 83.61