Preparation Of Cobalt Based MOFs-Derived Transition Metal Compound Electrode Materials And Research On Energy Storage Performance

With the rapid development of new energy resources,how to effectively store and utilize them is currently the most urgent task.Among various energy storage devices,hybrid supercapacitors have shown great applied potency in energy storage systems due to their safety and environmental protection,fast charging and discharging,and wide operating voltage.As the most important component,the electrode material is the key to determining whether hybrid supercapacitors can achieve practical applications.Therefore,transition metal compounds,such as hydroxides and sulfides,have become the most promising candidate materials due to their high theoretical capacity and reactivity.However,its poor conductivity and ion transfer rate limit its further application.To solve this problem,this paper adopts a reasonable microstructure construction and a multi-component collaborative strategy,multidimensional nanostructured Co（OH）F/CoS₂,hierarchical structure NiCo-LDH/CeO₂,and multicomponent hierarchical S-NiCo-LDH/CeO₂ electrode materials were prepared,respectively.The specific research content and results are as follows:1.In this paper,a multi-dimensional nanostructured CC@Co（OH）F/CoS₂ electrode was Obtained through simple two steps hydrothermal methods.It is found that Co（OH）F nanowires shorten the ion/electron transmission distance and reduce the transmission resistance,thereby improving the conductivity and stability of the material.The surface-attached CoS₂ facilitates full contact with the electrolyte and promotes redox reactions.Therefore,the capacity of the material was significantly increased to 233 m Ah g^-1.Hybrid supercapacitors assembled with Co（OH）F/CoS₂ and activated carbon exhibit high energy density(63.9 Wh kg^-1)and excellent cycle stability（107.0%,20000 cycles）.2.In this work,a hierarchical NiCo-LDH/CeO₂ electrode is formed using ion etching and a simple hydrothermal method.It was found that CeO₂ loaded on the surface of NiCo-LDH increased the active sites,thereby improving the specific capacity.The synergistic effect of NiCo-LDH and CeO₂ improves the conductivity and capacity of NiCo-LDH/CeO₂.Therefore,the prepared NiCo-LDH/CeO₂ electrode exhibits a high specific capacity of 321.7 m Ah g^-1.In addition,the assembled hybrid supercapacitors（NiCo-LDH/CeO₂//AC）exhibit excellent energy density(67.8 Wh kg^-1).After 20,000 cycles,it still maintains 70.4%of its initial capacity.This work presents a new idea for the development of high-performance transition metal hydroxide electrode materials.3.To further improve the electrochemical performance of electrode materials,multi-component hierarchical S-NiCo-LDH/CeO₂ electrodes were formed by introducing sulfur.The results show that S doping improves the conductivity and stability of NiCo-LDH.At the same time,the electron transfer between CeO₂ and NiCo-LDH interface significantly improves the conductivity and specific capacity of NiCo-LDH.Therefore,the prepared S-NiCo-LDH/CeO₂ electrode exhibits a high specific capacity of 459.2 m Ah g^-1.The hybrid supercapacitor assembled with S-NiCo-LDH/CeO₂ and activated carbon exhibits a high energy density of 72.2 Wh kg^-1.In addition,cycle stability（115%,20000 cycles）has been significantly improved.The above results indicate that the prepared multi-component hierarchical S-NiCo-LDH/CeO₂ electrodes are important for the development of high-performance electrode materials.