| Benefiting from lower costs,rich crustal resources,similar working principles,and comparable electrochemical performance,sodium-ion batteries have been considered to be the most likely replacement for lithium-ion batteries.However,the electrode materials that were originally suitable for lithium-ion batteries can not be applied well in sodium-ion batteries.Therefore,the development of electrode materials with high rate performance,low cost,and versatility is urgently needed for the practical application of sodium-ion batteries.Antimony-based materials are one of the competitive candidates for sodium-ion anode due to their high theoretical capacity.However,the antimony-based material has the problem of drastic volume expansion,which in turn causes some problems such as the severe pulverization of the material,which inevitably leads to poor rate performance and short cycling life.To solve those above issues,we successfully synthesized hollow antimony nanoparticles impregnated in open carbon boxes composite?Sb HPs@OCB?.We deeply studied the structural characteristics of Sb HPs@OCB material through a series of test and characterization methods,and explored its electrochemical properties,energy storage mechanism,and kinetic parameters at room temperature and high temperature.The main content of this article is as following:?1?Sb HPs@OCB composite material was synthesized by freeze-drying method using potassium chloride as a hard template,and various characterization tests were performed on it.We found that it has the following characteristics:50-200 nm hollow antimony nanoparticles are uniformly and completely embedded in a two-dimensional carbon wall of about 300 nm.A roubst Sb-O-C bond exists between the Sb nanoparticles and the carbon matrix.And the open carbon boxes are connected to form a three-dimensional structure.?2?Sb HPs@OCB material has been studied in detail for its sodium storage performance at 25?.The Sb HPs@OCB composite has a capacity performance of 270 m Ah g-1 at an ultra-high rate of 16 A g-1;and owns a reserved capacity of 217.7 m Ah g-1after 180 cycles under a large current density of 10 A g-1.In the assembled full battery,a reversible capacity of218 m Ah g-1 was retained after 67 cycles at a current density of 100 m A g-1.It also reveals that the energy storage mechanism of Sb HPs@OCB materials contributes to both the alloying reaction of Sb and the pseudocapacitance at room temperature.?3?We carefully explored the high-temperature sodium storage electrical properties for Sb HPs@OCB materials at 50°C.The results showed that Sb HPs@OCB material has excellent high-temperature electrical properties.It rendered a capacity performance of 345m Ah g-1 at an ultra-high rate of 16 A g-1.Under the large current density of 10 A g-1,it delivered a reversible capacity of 187 m Ah g-1 after 355 cycles.The analysis of CV and EIS curves showed that the Sb HPs@OCB electrode had significantly enhanced kinetics at 50°C,and the formation of amorphous Sb during charging state at high temperature was also found.It is worth noting that amorphous Sb was not found at room temperature.At the same time,energy storage mechanism of Sb HPs@OCB material was revealed at high temperature,showing emerge of the combined effect of pseudocapacitance and alloying reaction of Sb.The analysis and characterization of the active electrochemical materials after cycling showed that the Sb-O-C bond of the Sb HPs@OCB material still existed and the overall structure was integrated even after undergoing a long cycle under high rate. |
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