Ions and electrons dual transport channels regulated by nanocellulose for mitigating dendrite growth of zinc-ion batteries

Abstract

Zinc-ion batteries are considered a viable energy storage technology due to their superior safety, economic efficiency and environmental friendliness. Nevertheless, the drawbacks of the zinc anode, including dendrite growth, hydrogen evolution reaction and poor coulombic efficiency, seriously limit its practical application. Continuous interwoven networks with ions and electrons dual transport channels are effective in reducing the growth of zinc dendrites by promoting ion diffusion kinetics. Herein, carbon nanotubes (CNT)/cellulose nanofibers (CNF)/cellulose nanocrystals (CNC)/Zn self-supporting films with continuous interwoven network are constructed by a simple vacuum filtration and freeze-drying method. Furthermore, the pore size distribution of the self-supported films was modulated by adding CNF and CNC. When the CNF/CNC ratio was 8:1, the pore sizes of the zinc-ion anode films were concentrated in the range of 8–25 nm, had maximum electrical conductivity (1250 S/m), and excellent mechanical flexibility. As an optimized sample, the assembled symmetrical battery and the coin cell have excellent cycle performance, the efficiency of the assembled symmetrical battery was maintained at 100 % after more than 6000 cycles at 0.5 mA/cm², while the capacity retention was 99 % after 1500 cycles at 0.5 A/g for coin cell.