Effective Desolvation of Cation by Cellulose Nanofibrils for High-Performance Zinc-Ion Hybrid Supercapacitors

Aqueous zinc-based rechargeable electrochemical energy storage devices show promising ascendancy because of abundant resources and eco-friendly metals with high theoretic capacity. However, the irregular dendrite growth and byproduct on zinc foil are threatening their practical application. Herein, to mitigate the said drawback in the form of dendrite, a series of novel eco-friendly zinc-ion electrolytes prepared by hemp stem cellulose nanofibril (CNF) are presented in current research work. It provides novel way to inhibit the dendrite growth with different mechanism, which maintains the highly reactive anode surface to increase the nucleus rate rather than surface passivation. Besides, it also improves the conductivity of the liquid electrolytes to a superior record of 158.2 mS cm-1. Hydrogel electrolyte with CNF has an excellent conductivity of 107.8 mS cm-1 and higher mechanical strength as compared to prepared from cellulose. The desolvation effect of Zinc-ion hybrid supercapacitors assembled with CNF electrolytes present an ultra-high initial capacity of 450 mAh g-1 and a high capacity remaining after a long charge/discharge cycles. It reveals the promising potential that Zinc-ion hybrid supercapacitor (ZHS) can be used as a kind of outstanding energy storage devices. Simultaneously, it could achieve an energy density of 254.31 Wh kg-1 at a power density of 1131.67 W kg-1. Theoretical simulation results reveal that the strong hydrogen bonds and the proper size of CNF are of great significance for the outstanding performances. The remarkable findings of current research work will be great adaption in energy storage devices manufacturing industry.