Publication

Abstract : Rechargeable Zn-ion batteries are attractive energy storage devices owing to their high specific capacity, high cell voltage, eco-friendliness, and low cost. It is being used in various applications ranging from bulk to small flexible and wearable applications. In this work, the sphere-like morphology of β-MnO2 has been synthesized and used as a cathode in Zn-ion cells. The electrochemical half-cell performance of β-MnO2 has been analyzed using a lab-scale three-electrode setup using 1 M ZnSO4 electrolyte. Further, the pouch-type full cell having a 2 × 2 cm2 area has been fabricated and tested at different C-rates. Zn-ion pouch cell delivers a high specific capacity of 218.42 mAh g−1 at 64 mA g−1. The cycle stability of the cell has been carried out by continuously running the 250 galvanostatic charge-discharge cycles at 483 mA g−1 current density. The pouch cell showed a specific capacity retention of 81.11 % at the 250th cycle at a coulombic efficiency of 99 %. On the other hand, the effect of MnSO4 on the ZnSO4 has been studied using a coin cell (CR-2032) where the cell delivers as high as the specific capacity of 245.8 mAh g−1 at the current density of 64 mA g−1. β-MnO2 micro sphere-based Zinc ion cells delivered good electrochemical performance in both coin and pouch cell configurations. Therefore, β-MnO2 will be a potential cathode for aqueous rechargeable Zn-ion storage applications due to their good cycle life, good rate capability, and high specific energy.