Heterogeneous interface of Se@Sb@C boosting potassium storage

The development of potassium ion batteries is restricted by the intrinsic large ion radius, resulting in dramatic volume change of electrodes and slow faradic reaction in kinetics. High requirements are proposed for the structure design of anodes. In this work, Se coating-Sb nanocrystalls-three dimensional interconnected carbon networks (3D Se@Sb@C) heterogeneous structure was prepared by a low-temperature template-assisted CVD method. The network and sandwich structure can not only shorten the solid-state diffusion path of K+, but also alleviate the volume change of Sb. Moreover, the hetero interface between Se and Sb can form chemical bonding and further generate heterogeneous junctions in electrochemical reactions, providing more electron states at the Fermi energy level and reducing the ionic diffusion barrier of K+. Benefiting from it, the 3D Se@Sb@C electrode possess an optimized energy storage mechanism and exhibits an outstanding rate performance and an ultra-long lifespan of more than 5000 cycles with 87% of capacity retention, which is rarely reported for PIB anodes. It reveals the important role of heterogeneous structure in potassium storage, which can inspire other researchers to achieve superior electrochemical performance by interface engineering for electrode materials.