Sodium Ion Pre-Intercalation of δ-MnO2 Nanosheets for High Energy Density Aqueous Zinc-Ion Batteries

Abstract

With the merits of low cost, environmental friendliness and rich resources, manganese dioxide is considered to be a promising cathode material for aqueous zinc-ion batteries (AZIBs). However, its low ion diffusion and structural instability greatly limit its practical application. Hence, we developed an ion pre-intercalation strategy based on a simple water bath method to grow in situ δ-MnO2 nanosheets on flexible carbon cloth substrate (MnO2), while pre-intercalated Na+ in the interlayer of δ-MnO2 nanosheets (Na-MnO2), which effectively enlarges the layer spacing and enhances the conductivity of Na-MnO2. The prepared Na-MnO2//Zn battery obtained a fairly high capacity of 251 mAh g−1 at a current density of 2 A g−1, a satisfactory cycle life (62.5% of its initial capacity after 500 cycles) and favorable rate capability (96 mAh g−1 at 8 A g−1). Furthermore, this study revealed that the pre-intercalation engineering of alkaline cations is an effective method to boost the properties of δ-MnO2 zinc storage and provides new insights into the construction of high energy density flexible electrodes.

Ostwald ripening mechanism-derived MnOOH induces lattice oxygen escape for efficient aqueous MnO2–Zn batteries

“…In recent years, the main mechanism explored for manganese oxides (such as α-MnO 2 , 43,44 β-MnO 2 , 45,46 δ-MnO 2 , 47,48 γ-MnO 2 , 49 ε-MnO 2 (ref. 50), etc. )…”

High-Performance Layered CaV4O9-MXene Composite Cathodes for Aqueous Zinc Ion Batteries

“…Although vanadium-based materials have made great progress in the intercalation/ deintercalation of Zn 2+ , such materials often suffer from slow diffusion kinetics, irreversible phase transitions, and even structural collapse [20,21]. One of the most effective strategies is the introduction of metal ions such as M x V 2 O 5 •nH 2 O (M = Zn, Ca, Mg).…”