Metal-organic skeleton derived CoS2/NC as ultra-high anode for sodium-ion batteries
The increasing energy depletion and growing demand make the development of anode materials for sodium ion batteries urgent. Transition metal sulfides are of great interest because of their high theoretical specific capacity,and they are abundant and inexpensive,which help reduce costs,but there are problems such as structural degradation caused by volume changes during redox. Therefore,the study of anode materials with excellent performance for sodium ion batteries has become the focus of research. Cobalt sulfide particles confined in a relatively rigid matrix can effectively limit the volume expansion. In this paper,the metal-organic skeleton ZIF-67 was prepared by the solvothermal method,and then the nitrogen-doped CoS2 nanoparticles (CoS2/NC) were synthesized by high-temperature carbonization and sulfidation reaction using ZIF-67 as the precursor. They were tested by X-ray diffraction and other research methods to reveal the sodium storage mechanism of CoS2/NC. The results show that the CoS2/NC negative electrode material has a very high specific capacity and good cycling stability,and its specific capacity reaches 599.6 mAh/g at 0.06 A/g current density,and can still maintain a high capacity of 455.4 mAh/g after 500 cycles at 1200 mA/g current density. In addition,the smaller electrochemical impedance and higher capacitance contribution ensure the excellent multiplicative performance of the electrode material and the cycling performance at high current density. The strategy is simple to operate,significantly improved and widely applied,and has a broad application prospect in sodium ion batteries. The CoS2/NC electrode exhibits excellent sodium storage performance and is expected to be the next generation of high-performance anode material. The modification strategy is simple and effective,and can be widely used in other electrochemical energy storage devices.
CoS2/NC compositesodium ion batteriesanode materialelectrochemical propertiesmetal organic frame
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