Space-confined growth of Bi2Se3 nanosheets encapsulated in N-doped carbon shell lollipop-like composite for full/half potassium-ion and lithium-ion batteries

Metal Selenides with layer structure has obvious advantages to store guest alkaline metal ions , promote cycling stability and accelerate diffusion kinetics when applied as electrode for batteries . Among them, layer structured Bi 2 Se 3 with large interlayer spacing is expect to have potential applications in rechargeable batteries . In this study, Bi 2 Se 3 @NC composite with lollipop-like structure was synthesized by conveniently hydrothermal combined subsequent selenization process and then applied as high-performance anodes for both PIBs and LIBs . The synergistic effects between Bi 2 Se 3 and N-doped carbon shell endow it excellent performances anode for PIBs (~ 201.2 mA h g −1 after 1200 cycles at 100 mA g −1 , and 130.5 mA h g −1 after 2000 cycles at high current density of 1000 mA g −1 ). Bi 2 Se 3 @NC also exhibited outstanding performance as anode for LIBs (~ 1005.8 mA h g −1 after 300 cycles at 100 mA g −1 ). The reaction kinetics analyses results revealed that pseudocapacitance contribution play important role for the excellent electrochemical performances. It is worth to note that the Bi 2 Se 3 @NC//PTCDA-450 potassium-ion full cells were successfully assembled, and 122.3 mA h g −1 was remained after 200 cycles at 100 mA g −1 (the coulombic efficiency can keep at ~ 100%). In addition, ex-situ X-ray diffraction and HRTEM were adopted to explore the phase evolution of Bi 2 Se 3 @NC during charge-discharge processes and density functional theory (DFT)-based first-principle calculations reveal that Bi 2 Se 3 has a lower diffusion barrier and adsorption energy than that of Bi 2 O 3 . These results prove the merits of Bi 2 Se 3 @NC and its application potential as suitable anode material for half/full PIBs and LIBs .