Study And Application Explorations Of Key Materials For High-Performance Sodium-Ion Batteries

Sodium-ion batteries(SIBs)have been widely advocated as one of the most promising post-lithium-ion batteries due to the huge abundance and low cost of sodium resources.The search for earth-abundant and high-performance electrode materials for sodium-ion batteries has been an active area in the past several year.In this thesis,we briefly introduced the research progress of sodium-ion batteries,and then discussed the advantages and disadvantages of current electrode materials.At last,we aimed at high-performance transition metal oxides and sulfides electrode materials to construct high energy density sodium-ion batteries.The main research contents are listed as follows:(1)We firstly designed a configuration of iron-based sodium-ion full batteries with both electrode materials based on the same earth abundant and environmentally friendly element-iron.Such prototypes have a working voltage of-2 V,specific energy density of?136 Wh/kg and excellent cycling stability with nearly no capacity loss.(2)We systematically studied amorphous MoS3 as the earth-abundant and high-performance sodium-ion batteries anode material.Such kind of amorphous MoS3 electrodes exhibit excellent electrochemical performance with large specific capacity(-615 mAh/g),high-rate capability(50 A/g)and outstanding cycling stability.Besides,their dense high-loading electrodes can deliver an appealing areal capacity of-6.71 mAh/cm2 and a volumetric capacity of?1000cmAh/cm3.(3)We proposed a concept of sulfur-equivalent cathode materials by virtue of transition metal sulfides,and demonstrate the great potential of amorphous MoS3 as such a material for room-temperature Na-S and Li-S batteries.When evaluated in room-temperature Na-S batteries,amorphous MoS3 electrodes exhibit sulfur-like behavior with large reversible specific capacity(?1022 mAh/g),exceptional high rate capability(20 A/g)and excellent cycle life of 1000 cycles.