Electrochemical behavior of nanostructured MnO2/C (Vulcan®) composite in aqueous electrolyte LiNO3

Abstract

The electrolytic solutions of contemporary Li-ion batteries are made exclusively with the organic solvents since anodic materials of these batteries have potentials with greater negativity than the potential of the water reduction, thus the organic electrolytes can withstand the voltages of 3-5 V that are characteristic for these batteries. Ever since it was discovered that some materials can electrochemically intercalate and deintercalate Li+ ions in aqueous solutions, numerous studies have been conducted with the aim of extending operational time of the aqueous Li-ion batteries. Manganese oxide has been studied as the electrode material in rechargeable lithium-ion batteries with organic electrolytes. In this paper its electrochemical behavior as an anode material in aqueous electrolyte solutions was examined. MnO2 as a component of nanodispersed MnO2/C (Vulcan®) composite was successfully synthesized hydrothermally. Electrochemical properties of this material were investigated in aqueous saturated LiNO3 solution by both cyclic voltammetry and galvanostatic charging/discharging (LiMn2O4 as cathode material) techniques. The obtained composite shows a relatively good initial discharge capacity of 96.5 mAh/g which, after 50th charging/discharging cycles, drops to the value of 57mAh/g. MnO2/C (Vulcan®) composite, in combination with LiMn2O4 as a cathode material, shows better discharge capacity compared to other anodic materials used in aqueous Li-ion batteries according to certain studies that have been conducted. Its good reversibility and cyclability, and the fact that hydrothermal method is simple and effective, makes MnO2/C(Vulcan®) composite a promising anodic material for aqueous Li-ion batteries.

Keywords

• aqueous lithium-ion batteries
• li-ion intercalation
• manganese oxide