Constructing a directional ion acceleration layer at WO3/ZnO heterointerface to enhance Li-ion transfer and storage

Abstract

Heterointerface plays the key role to adjust and enhance the charge transport properties of composite electrode materials in Li-ion batteries. However, many studies focus on heterostructure powder material that evenly distribute in the slurry, which results in disorder arrangement of heterostructure units in powder electrode and many built-in electric fields failure in charge transfer. Herein, tungsten trioxide/zinc oxide (WO3/ZnO) heterostructure film electrode with directional built-in electric field (a charge acceleration layer) is fabricated by WO3 hexagonal flower arrays with a deposited layer of ZnO QDs supported by conductive carbon cloth substrate. The planar heterojunction and directional built-in electric fields help to enhance Li-ions transport in charge-discharge processes. As expected, the WO3/ZnO heterostructure composite electrode exhibits remarkable reversible discharge capacity (~1500 mAh g−1 at 0.28C), high rate performance (~500 mAh g−1 at 9.0C), and excellent cycling stability (1100 mAh g−1 at 1C after 300 cycles). This work provides an effective strategy for constructing heterostructure film anode with a directional charge acceleration layer to enhance the lithium ion tranfer and storage.