An ultrathin nanocellulosic ion redistributor for long-life zinc anode

Metallic zinc (Zn) has garnered extensive research interest as a promising anode candidate for aqueous zinc batteries (AZBs) owing to its high theoretical capacity and low redox potential. However, its practical application is severely plagued by the issue of uncontrolled Zn dendritic growth and short lifetime mainly as a result of nonuniform Zn-ion (Zn2+) flux distribution across the Zn anode/electrolyte interface. Herein, we propose a feasible and efficient strategy to homogenize the ion flux by building an ultrathin cellulose nanofiber (U-CNF, thickness of less than 1 μm) ion redistributor from waste biomass, which shows remarkable talent in addressing the dendrite formation issue without compromising the low-cost and environmentally friendly nature of AZBs. With this interfacial design, exceptional long-cycle-life (over 2500 h at 1 mA cm−2), excellent rate capability (low voltage hysteresis of 238 mV at 40 mA cm−2), and high reversibility (average Coulombic efficiency of 99.14% over 850 cycles) of Zn plating/stripping performance are synchronously realized. Furthermore, the long-term cyclability and reliability of practical Zn||MnO2 batteries are also demonstrated with the incorporation of the U-CNF ion redistributor. Considering the simplicity and effectiveness, this proof-of-concept study may imply a promising physical route toward dendrite-free Zn anode for AZBs.