Bean pod-like hollow Zn2SnO4/SnO2 heterostructures in N-doped carbon nanofibers as anode material for high performance lithium storage

Abstract

Tin-based composites have been extensively investigated as a potential anode for high performance lithium-ion batteries (LIBs) up until this point. However, because of extreme volume expansion and crystal crushing, the researchers have consistently experienced a loss in capacity during lithiation and alloying. To buffer the volume change and achieve superior rate capability, the hollow cube-shaped Zn2SnO4/SnO2 which is wrapped with one-dimensional N-doped carbon nanofibers (CNFs) is prepared. The composites display a delicate bean pod-like heterointerface structure, in which the built-in electric field between Zn2SnO4 and SnO2 can help to speed up the transportation of Li-ions during lithiation and delithiation processes. Additionally, the abundant Zn2SnO4/SnO2 heterointerfaces expose more active sites and make it easier for electrolyte and Li-ion to penetrate. And the N-doped carbon skeleton outside of the Zn2SnO4/SnO2 can help to keep the structural integrity and suppress volume expansion during cycling. As expected, the as-prepared samples exhibit excellent rate performance and a very high ultimate discharge capacity of 765.9 mA h g−1 after 500 cycles at current density of 1.0 A g−1. Furthermore, a full-cell with a prelithiated Zn2SnO4/SnO2 @CNFs-600 anode and a LiFePO4 cathode also displays superior rate and cycling performance. This work highlights the significance of chemical heterointerface engineering in the design of high-performance electrodes for LIBs.