Design And Electrochemical Performance Study Of Metal Sulfide Nanomaterials

Alkali metal ions play an important role in the field of electrochemical energy storage.Among them,lithium ion batteries are widely used in the field of portable electronic devices and electric vehicles.Meanwhile,the researches of sodium ion battery and potassium ion battery have been an active area.Firstly,the status quo of the three types of alkali metal ion batteries and their electrode materials are briefly introduced in this thesis.Secondly,the thesis introduces the two subjects the author has completed.Both are based on metal sulfide nanomaterials which are used as anode materials for various alkali metal ion batteries.In the first work,we designed and synthesized a carbon-coated hierarchical tin disulfide nanosheet assemblies and tested its electrochemical performance as an anode electrode material for lithium ion batteries and sodium ion batteries.Experiments have shown that this special morphology of tin disulfide material shows a very high specific capacity(~980 m Ah/g),great cycle stability(300 cycles)and superior rate characteristics(620 m Ah/g under 10 A/g)in lithium ion batteries.At the same time,it shows good capacity(~600 m Ah/g)and cycle stability in the sodium ion battery.In the second work,we prepared a fibrous molybdenum trisulfide nanosheets material and studied its electrochemical performance in the three types of alkali metal ion batteries.In lithium-ion batteries,this amorphous molybdenum trisulfide material exhibits a high specific capacity(827 m Ah/g),excellent cycle stability(500 cycles)and excellent rate characteristics(624 m Ah/g under 10 A/g).In the sodium-ion battery,this electrode material exhibits high specific capacity(600 m Ah/g)and great rate performance(340 m Ah/g under 5 A/g).In addition,good specific capacity and cycle stability are also exhibited in potassium ion batteries.