Cyclodextrin-assisted synthesis of nanostructured manganese oxide cathodes for high-performance aqueous Zn-ion batteries

Abstract

Secondary aqueous zinc batteries (AZIBs) have gained substantial interest recently because of their excellent safety, affordability, and minimal ecological footprint. This study introduced a novel approach for synthesizing MnO2 using a straightforward one-step hydrothermal method in the presence of β-cyclodextrin and was employed as a cathode material for secondary AZIBs for the first time. The study systematically investigated the influence of β-cyclodextrin concentration on the morphology, crystal orientation, and electrochemical properties of MnO2 electrodes. The research found that varying the concentration of β-cyclodextrin resulted in different nanostructured MnO2 morphologies, namely δ-MnO2 and α-MnO2. This is the first time such distinct morphologies have been linked to β-cyclodextrin concentration. According to our experimental findings, the optimal β-cyclodextrin concentration for this study was 1.0wt%. The optimized 1.0wt%-CDM electrode exhibited an impressive discharge capacity of 205.2 mAh g-1 and 177.2 mAh g-1 when operated at 0.5 A g-1 and 1 A g-1, respectively. Notably, the 1.0wt%-CDM electrode maintained an impressive capacity of 129.2 mAh g-1 even after 1000 cycles, surpassing the performance of the pristine δ-MnO2 electrode (14.8 mAh g-1). This research highlights the potential of MnO2 nanostructures as promising candidates for developing commercial electrode materials.