Preparation Of Tin-based Compound Anode Materials For Na Storage Property Investigation

Sodium-ion batteries（SIBs）have attracted the attention of researchers in large-scale energy storage applications due to their abundant natural sodium resources,low cost,wide geographical distribution and similar working mechanism to lithium-ion batteries.The high theoretical specific capacity of negative-intermediate transition metal compounds（oxides and selenides）in sodium-ion batteries has attracted the attention of researchers,but their development has been hampered by their severe volume changes.It is still a great challenge to explore a high performance electrode material for sodium ion batteries.Due to its advantages of high theoretical capacity and low cost,tin-based compounds are considered as promising cathode materials for the next generation of sodium ion batteries.However,during the process of sodium ion embedding/ejection,its volume changes greatly,resulting in irreversible capacity loss and poor cycling performance.Tin and tin-based compounds are considered promising next-generation anode materials for sodium-ion batteries because of their high theoretical capacity and low cost.However,the large volume changes during sodium insertion/extraction result in irreversible capacity loss and poor cycle performance.Therefore,a new 3D porous carbon-encapsulated nano-tin-based oxide composite was prepared using strategies such as freeze-drying,sintering and filtration.The porous carbon layer not only prevents nanoparticles from aggregating,which ensures structural integrity,but also greatly improves the conductivity and high-rate performance of the material.Meanwhile,the Bi-SnO_x heterojunction structure accelerates charge transfer and significantly improves the sodium ion diffusion efficiency.Therefore,the Bi/SnO_x@C electrode material in SIBs showed superior rate performance and cycling stability compared to Bi@C and SnO_x@C.This strategy provides some reference for improving the electrochemical performance of other metal oxide materials.Metal selenides have received significant attention as negative electrode materials for sodium-ion batteries due to their relatively high theoretical specific capacity and excellent conductivity.However,their large volume changes during cycling lead to reduced cycling stability and rate performance.To address this issue,CoSe₂-SnSe nanoparticles were incorporated into carbon nanofibers（CoSe₂-SnSe@CNF）via a dispersion mixing,electrospinning,and calcination process.In SIBs,the electrochemical performance of CoSe₂-SnSe@CNF was superior to that of CoSe₂@CNF and SnSe@CNF due to the synergistic effect of combining the two selenides and the presence of carbon nanofibers that reduced volume expansion and nanoparticle aggregation during the reaction.CoSe₂-SnSe@CNF composite demonstrates excellent electrochemical properties,with a reversible specific capacity of 354.6 mAh g^-1 after 100 cycles at a current density of 0.1 A g^-1.