In the realm of energy storage, a team of researchers from Aalto University in Finland has made significant strides in improving the performance of aqueous zinc batteries (AZBs). The team, led by Ibrahim Al Kathemi and including Vishnu Arumughan, Marcel Kröger, Ira Smal, Mohamed Zbiri, Eero Kontturi, and Roza Bouchal, has focused on enhancing the compatibility of zinc anodes with separators, a critical component of batteries that is often overlooked.
Aqueous zinc batteries are a promising alternative to lithium-ion batteries due to their safety, cost-effectiveness, and environmental friendliness. However, they face challenges such as dendrite growth, hydrogen evolution reaction, and poor cycling stability, which are largely attributed to the limited compatibility of zinc anodes with conventional separators. The researchers aimed to address these issues by exploring the potential of separator design in optimizing battery performance.
The team utilized nanochitin, derived from waste shrimp shells, to fabricate separators with varying concentrations of amine and carboxylic functional groups. They investigated how the type and concentration of these groups influence the separator’s properties and performance. In a mild acidic electrolyte that protonates the amine groups, the results showed that the density of both ammonium and carboxylic groups in the separators significantly affected water structure and ionic conductivity.
Quasi-Elastic Neutron Scattering (QENS) revealed that low-functionalized chitin, particularly with only ammonium groups, promotes strongly bound water with restricted mobility. This enhancement in water structure led to improved zinc plating and stripping kinetics. The separators exhibited exceptional zinc stability over 2000 hours at low current densities (0.5 mA/cm2), maintaining low overpotentials and stable polarization. Additionally, the full cell consisting of zinc and sodium vanadium oxide showed a cycle life of over 2000 cycles at 2 A/g, demonstrating the compatibility of the nanochitin-based separators with low concentrations of functional surface groups.
The practical applications of this research for the energy sector are significant. By improving the performance and stability of aqueous zinc batteries, this study paves the way for more efficient and reliable energy storage solutions. The use of waste shrimp shells to fabricate separators also highlights a sustainable approach to battery design, aligning with the growing demand for environmentally friendly technologies.
The research was published in the journal Advanced Materials, a leading publication in the field of materials science. The findings underscore the importance of simple separator design in enhancing the overall performance of aqueous zinc batteries, offering a promising avenue for future developments in energy storage technologies.
This article is based on research available at arXiv.