Stabilizing aqueous zinc-ion battery with cellulose/graphene hybrid separator through dual regulation of fast desolvation and ion deposition

Abstract

The rampant zinc dendrites growth in zinc metal anode leads to poor rechargeability and short lifespan, and significantly limits the practical applications of aqueous zinc-ion batteries (ZIBs). Herein, a regenerated-cellulose/graphene (RCG) separator is developed to improve the stability of the Zn anode and extend the lifespan of ZIBs. The glucose units in cellulose chains can modify the solvation configuration of Zn²⁺ ions, facilitating the Zn²⁺ ions transfer and regulating Zn deposition kinetics. Meanwhile, the graphene additive induces Zn (002) oriented deposition by forming a low lattice mismatch interface between the separator and Zn (002) crystal plane. Furthermore, the hybrid separator exhibits significantly higher tensile strength (91.23 MPa) compared to previously reports, which is a crucial for preventing short circuits caused by zinc dendrites or external force during cell operation. Accordingly, the Zn anode with the RCG separator achieves a record operational lifetime of 7000 h at 0.5 mA cm⁻², surpassing previously reported results. Moreover, the zinc-ion hybrid supercapacitor with the RCG separator exhibits a high capacity retention of 81.62 % after 10000 cycles. This work offers a new strategy to construct dendrite-free ZIBs, marking a great step forward in the practical application of ZIBs.