Performance study of magnesium-polyaniline rechargeable battery in 1-ethyl-3-methylimidazolium ethyl sulfate electrolyte

A novel electrolyte system for the magnesium-polyaniline rechargeable battery containing 0.025 M magnesium sulfate (MgSO4) in 1-ethyl-3-methylimidazolium ethyl sulfate (EMIES) has been developed. The electrochemical properties of magnesium and polyaniline electrodes in the MgSO4–EMIES solution are investigated, respectively. The results show that the corrosion potential of magnesium is −1.55 V (vs. SCE) in 0.025 M MgSO4–EMIES and magnesium has high dissolution and deposition reversibility in the solution. Polyaniline shows good oxidation and reduction reversibility in 0.025 M MgSO4–EMIES and the loose and porous structure of polyaniline is helpful to the doping and de-doping of anions as well as electron transfer. The study of the effect of current density on discharge capacity shows that the magnesium-polyaniline battery has higher discharge capacity at lower current density. At 667 mA g−1, magnesium-polyaniline battery has an average discharge potential of 2.10 V and the first cycle discharge capacity could be 116 mAh g−1. The magnesium-polyaniline battery has good cycle performance and the coulombic efficiency of the 60th cycle can be nearly 95%. The new cheap and simple magnesium-polyaniline battery is of great significance in the future rechargeable battery.