Silver decorated beta-manganese oxide nanorods as an effective cathode electrocatalyst for rechargeable lithium–oxygen battery

In this paper, Ag nanoparticles decorated β-MnO 2 nanorods are studied as cathode catalyst for rechargeable lithium–oxygen battery (LOB). β-MnO 2 nanorods are prepared using a simple hydrothermal method based on MnO 4 − and the decoration of Ag nanoparticles is performed by in-situ composite technique in the presence of polymeric additives. The as-prepared materials are characterized by XRD , TEM, XPS , BET and Raman spectrum. Electrochemical charging and discharging capacity of β-MnO 2 and Ag/β-MnO 2 electrodes are investigated at the current density of 0.02   mA   cm −2 in the voltage window of 2.0–4.0   V. LOB with Ag/β-MnO 2 electrode shows an initial discharge capacity of 873   mA   hg −1 (electrode) , with reversible charge capacity of 811   mA   hg −1 (electrode) while battery with only β-MnO 2 has discharge capacity of 541   mA   hg −1 (electrode) and charge capacity of 445   mA   hg −1 (electrode) . Ag/β-MnO 2 nanocomposite electrode shows good rate capability and cycle stability. After 10   cycles, the capacity of 742   mA   hg −1 (electrode) is still retained at the current density of 0.02   mA   cm −2 while only 219   mA   hg −1 (electrode) is retained at 0.5   mA   cm −2 . The capacity retention rate is 84.9% and 70.2% at 0.02 and 0.5   mA   cm −2 , respectively. During discharging, Li 2 O is the main discharge product and no Li 2 CO 3 is formed. The results show that the electrochemical performance of β-MnO 2 is greatly enhanced when Ag nanoparticles are introduced. And it is highly effective for decreasing the charging potential close to the theoretical value. Ag nanoparticles can enhance the electronic conductivity of the network. The study confirms that Ag/β-MnO 2 catalyst is a promising effective catalyst for LOB.