posted on 2024-02-01, 23:03authored byAina Zhang, Xiuxiu Yin, Xu Zhang, Junjie Ba, Junpeng Li, Yingjin Wei, Yizhan Wang
Delta
MnO2 (δ-MnO2) is a
promising
cathode material for aqueous zinc ion batteries. However, the electrochemical
performance of a δ-MnO2 cathode is severely limited
by sluggish reaction kinetics, low electronic conductivity, and inferior
structural stability. In this study, we propose a simple and general
approach for the preintercalation of large-sized organic cations between
the layers of δ-MnO2. Our method is based on layer-by-layer
electrostatic assembly of colloidal building blocks consisting of
MnO2 nanosheets and various organic cations. The preintercalation
results in unprecedented expansion of the interlayer spacing to more
than 1.0 nm, thereby significantly enhancing the kinetics of ionic
diffusion. These introduced cations act as supportive pillars and
contribute to the modulation of the electronic structure of δ-MnO2, ultimately enhancing its structural stability and electronic
conductivity. Electrochemical evaluations demonstrate superior performance
in terms of capacity, rate capability, and cycling stability compared
with that of a pristine δ-MnO2 cathode. The findings
provide valuable insights into the design of high-performance cathode
materials with improved ion diffusion kinetics and superior energy
storage capabilities.