Bi3Se4 nanodots in porous carbon: A new anode candidate for fast lithium/sodium storage

Abstract

• A new Bi 3 Se 4 -based anode material is successfully developed and firstly applied in lithium and sodium ion batteries. • For the first time, in-situ XRD is employed to disclose the lithium storage mechanism of Bi 3 Se 4 /C-800 anode. • C-Se bonds are proved to strengthen the heterointerface and improve reaction knietics via experiments and theoretical calculations. • Bi 3 Se 4 /C-800 electrode exhibits ultra-long cycling life and fast-charging capability. Bismuth selenide has attracted considerable attention as anode materials due to its high theoretical capacity. However, its development has been limited to Bi 2 Se 3 -based composites up to now. Herein, a facile strategy to regulate the atomic ratio of Bi x Se y is propsed and a new Bi 3 Se 4 -based anode material is successfully developed. Firstly, in-situ XRD technique is employed to disclose the combined conversion and alloying reactions mechanism. Besides, a uniform structure with Bi 3 Se 4 nanodots embedded within a sheet-like carbon framework is verified, ensuring fast kinetics and efficient alleviation of stress derived from dramatic volume expansion. Furthermore, experimental results combined with theoretical calculations prove the formation of robust interfacial C-Se bonds, which could simultaneously enhance the inherent bulk electronic conductivity and accelerate ionic transportation. As expected, Bi 3 Se 4 -based electrode achieves an ultralong cycle life of 1500 cycles at a high current density of 2 A g −1 and fast lithium storage capability of 211 mAh g −1 at an ultrahigh rate of 20 A g −1 . Such exceptional performance fully proves the huge potential of Bi 3 Se 4 -based electrode and also provides guidance for the exploration of other high-performance Bi x Se y -based anodes. A new Bi 3 Se 4 -based anode material is proposed via facilely optimizing the selenization temperature. Advanced in-situ technique combined with computational simulations are employed to evaluate phase evolution, lithium storage mechanism and electrolchemical performance. Consequently, Bi 3 Se 4 /C hybrid exhibits fast-charging capability and durable cycling life benefiteed from robust structure and stable C-Se bonds.