电化学置换反应制备石墨烯基纳米无定型锑复合阳极用于高性能钠离子电容器的构筑OA北大核心CSTPCD

Sodium-ion energy storage devices are considered as an ideal substitute for popular lithium-ion counterparts because of its resource richness and environmental friendliness.Among the various sodium-ion energy storage devices,sodium-ion capacitors(SICs)have the combined advantages in high energy and power densities as well as long-term cycling stability in theory.Antimony(Sb)is considered as an attractive anode material for SICs due to its high theoretical capacity of 660 mAh∙g-1,low operating potential(0.5-0.8 V vs.Na/Na+),and high density of 6.68 g∙cm-3.However,the large volume change of Sb during the Na+insertion leads to fast decay in capacity and poor rate capability,which becomes a fundamental issue greatly hindering the practical application.Herein,a facile galvanic replacement approach is proposed for the synthesis of an ultrafine amorphous Sb nanoparticles anchoring on carbon coated two-dimensional(2D)reduced graphene oxides(RGO).Half-cell test(vs.metal Na)shows that as-prepared Sb-C@RGO anode delivers a high specific capacity of 521.5 mAh∙g-1 at 0.1 A∙g-1.As the current density increases to 10 A∙g-1,Sb-C@RGO anode still maintains a specific capacity of 83.5 mAh∙g-1,suggesting its high-rate properties.The excellent Na+charge storage property of Sb-C@RGO anode is primarily due to its unique 2D hybrid architecture,which largely increases the atomic interface contact with Na+and shortens ion diffusion path,thus facilitating ion/electron transfer.To demonstrate the feasibility of Sb-C@RGO as the high-performance electrode for emerging energy-storage devices,a hybrid cell configuration(e.g.,SIC)was fabricated by employing the Sb-C@RGO as the negative electrode(battery type)and home-made activated carbon(PDPC)as the positive electrode(capacitive type)in a Na+based organic electrolyte.This SIC is capable of operating at a high voltage of 4.0 V and exhibiting a high energy density of 140.75 Wh∙kg-1 at a power density of 250.84 W∙kg-1.Even the power density is magnified～50 times to 12.43 kW∙kg-1,this SIC still delivers a high energy density of 55 Wh∙kg-1.Within a short charge/discharge of～3.2 min,this SIC can store/release quite a high energy density of 108.5 Wh∙kg-1,which represents the remarkable performance among the reported Sb-based capacitors.In addition,this SIC shows the good cycling stability with an acceptable capacity retention value of 66.27%after 1000 cycles at a current density of 2 A∙g-1.Our results may provide insight into the rational design and construction of high-capacity Sb-based anode materials for advanced sodium-ion based energy storage devices.