Regulating Zn²⁺ solvation shell with a hydrogen-bonded Carboxymethyl cellulose composite electrolytes for versatile...

Polymer electrolytes with high mechanical stability and versatility are increasingly critical for flexible wearable electronics. This study introduces a method for incorporating montmorillonite (MMT) into a carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) matrix to develop a high-performance nanostructured composite electrolyte. This approach aims to establish robust nanoscale interfacial interactions between montmorillonite nanosheets and the polymer matrix. The well-developed pore structure within the system and the abundant active sites on the MMT nanosheets contribute to the ionic conductivity of the composite electrolyte, which achieves 23.96 ± 0.25 mS cm^-1 at room temperature and expands the voltage window to 2.4 V. The assembled Zn || Zn symmetric cells demonstrate reversible stripping/plating over 1500 h at 1 mA cm^-2 current density. Density Functional Theory (DFT) calculations reveal that Zn²⁺ preferentially binds with the polymer, regulating its solvation effect with water and suppressing the formation of zinc dendrite. The electrolyte shows excellent adaptability and versatility with various electrodes. For instance, flexible zinc-ion hybrid capacitors (FZHC) retain 88.6 % capacity after 90,000 cycles at 10 A g^-1 and maintain normal function under harsh conditions such as cutting, bending, and pressing. This electrolyte holds significant potential for flexible energy storage applications.