Study On Electrospinning Preparation And Lithium/Potassium Storage Properties Of Antimony-Based Anode Materials

Antimony-based anode materials have attracted wide attention from researchers due to their high theoretical specific capacity produced by the alloying reaction.However,the huge volume expansion during the alloying process severely limits its practical application in lithium/potassium ion batteries（LIBs/PIBs）.Based on the synthesis conditions and additives,the Sb₂Se₃/Sb/C nanofiber,free-standing Sb₂Se₃/Sb/C nanofiber membrane and flexible Sb₂Te₃/C nanofiber membrane were synthesized through electrospinning followed by controlled annealing.Through a series of physical characterization and electrochemical performance testing,the structural characteristics of the samples and the lithium/potassium storage performance are systematically studied.The specific work content is as follows:1.At first,there is introduces the Sb₂Se₃/Sb/C nanofibers.Use Sb₂Se₃ itself as a template,the hierarchical Sb₂Se₃ and Sb particles fully encapsulated into carbon nanofibers have been in-situ synthesized by electrospinning followed by controlled annealing.Research shows that this special composite structure is conducive to the transmission and storage of Li⁺/K⁺,and exhibits an outstanding cycle stability and rate performance.In LIBs,at a current density of 0.1 A g^-1,it can provide an ultra-high specific discharge capacity of 764 m Ah g^-1 after 300 cycles.When a current density of1 A g^-1 was applied,the discharge capacity retains at 429 m Ah g^-1after 1000 cycles.More prominently,when cycling at an ultra-high current density of 5 A g^-1,the discharge specific capacity is surprisingly maintained at 342 m Ah g^-1.In PIBs,at a current density of 0.1 A g^-1,the electrode exhibited a specific discharge capacity of 200 m Ah g^-1 after100 cycles.2.Through the study of above research,a flexible Sb₂Se₃/Sb/C nanofiber membrane was successfully synthesized by adding an appropriate amount of TEOS.Utilizing the excellent coupling effect of TEOS,the Sb Cl₃-TEOS-PVP/PAN bonding layer solves the adverse effects of the incompatibility and low adhesion between the polymer and the transition metal ion,which can suppress structural collapse and enhance the heat resistance of precursor nanofibers during the heat treatment process.Meanwhile,the Sb₂Se₃/Sb-Si O₂-C dense bonding layer improves the mechanical flexibility of the nanofibers,so that the prepared nanofiber membrane can return to its original shape after bending,folding,and kneading.At the same time,the dense,uniform,and stable structure have also achieved a superb electrochemical performance.In LIBs,the discharge specific capacity of Sb₂Se₃/Sb/CN-0.5T（TEOS added with 0.5m L）electrode is as high as 734 m Ah g^-1 at 0.1 A g^-1.After 1000 cycles at a current density of 1 A g^-1,the specific discharge capacity remained at 440 m Ah g^-1.Among PIBs,the Sb₂Se₃/Sb/CN-0.5T electrode has a specific discharge capacity of 372 m Ah g^-1 at 0.05 A g^-1.The specific discharge capacity after 300 cycles at 0.1 A g^-1 display344 m Ah g^-1.3.Applying the above synthesis experience to Sb₂Te₃ with higher conductivity and volumetric energy density,the free-standing porous Sb₂Te₃ carbon nanofiber（P-Sb₂Te₃/CN）membrane was obtained by blending an appropriate amount of polymethyl methacrylate（PMMA）.The porous structure provides sufficient free buffer space for the volume expansion of Sb₂Te₃,and the larger specific surface area conferred more Li⁺intercalation/deactivation sites.With the support of TEOS,the P-Sb₂Te₃/CN material with excellent flexibility has achieved splendid lithium storage performance.It delivers a specific discharge capacity of 427 m Ah g^-1 after 1000 cycles at a current density of 1A g^-1,and the capacity retention rate is 88.9%.Simultaneously,at a high current density of 5 A g^-1,it can output a considerable discharge capacity of 301 m Ah g^-1.