A nanofibrillated cellulose/Al(OH)3/polytetrafluoroethylene hybrid protective layer enabling dendrite free Zn anodes for rechargeable aqueous batteries

Abstract

Aqueous zinc ion batteries (ZIBs) are considered as promising options for energy storage devices due to their high safety and abundant resources. However, Zn dendrites and short circuits pose a significant challenge. To address these issues, a hybrid protective membrane of nanofibrillated cellulose (NFC)/Al(OH)₃/polytetrafluoroethylene (PTFE) was fabricated and coated on the surface of a zinc metal anode. The in situ formation of Al(OH)₃ nanoparticles created nano-pores inside the dense NFC network, while the addition of PTFE improved the adhesion of the protective membrane to the surface of zinc metal. The NFC/Al(OH)₃/PTFE coating layer restricted the access of active water and anions to the electrode/electrolyte interface by dehydrating zinc ions, thus preventing water and anion-induced corrosion. With the NFC/Al(OH)₃/PTFE coating layer, zinc symmetric batteries exhibited significantly improved cycling performance with highly stabilized charge/discharge profiles, outperforming bare zinc symmetric batteries. Furthermore, full vanadium dioxide (VO₂)||NFC/Al(OH)₃/PTFE@Zn batteries demonstrated a high initial specific capacity of 406.2 mA h g⁻¹ at 2 A g⁻¹ and excellent cycling stability with a 94% retention of initial capacity after 300 cycles, and 72% after 3300 cycles, making them practical for energy storage applications.