Nanocellulose_Carboxymethylcellulose Electrolyte for Stable, High_Rate Zinc_Ion Batteries

Abstract

Abstract Aqueous Zn ion batteries (ZIBs) are one of the most promising battery chemistries for grid_scale renewable energy storage. However, their application is limited by issues such as Zn dendrite formation and undesirable side reactions that can occur in the presence of excess free water molecules and ions. In this study, a nanocellulose_carboxymethylcellulose (CMC) hydrogel electrolyte is demonstrated that features stable cycling performance and high Zn 2+ conductivity (26 mS cm _1 ), which is attributed to the material's strong mechanical strength (�70 MPa) and water_bonding ability. With this electrolyte, the Zn_metal anode shows exceptional cycling stability at an ultra_high rate, with the ability to sustain a current density as high as 80 mA cm _2 for more than 3500 cycles and a cumulative capacity of 17.6 Ah cm _2 (40 mA cm _2 ). Additionally, side reactions, such as hydrogen evolution and surface passivation, are substantially reduced due to the strong water_bonding capacity of the CMC. Full Zn MnO 2 batteries fabricated with this electrolyte demonstrate excellent high_rate performance and long_term cycling stability (>500 cycles at 8C). These results suggest the cellulose_CMC electrolyte as a promising low_cost, easy_to_fabricate, and sustainable aqueous_based electrolyte for ZIBs with excellent electrochemical performance that can help pave the way toward grid_scale energy storage for renewable energy sources.